Vivor — evidence-based supplement information

Magnesium

How much: 200 to 400 mg of magnesium a day. Citrate or glycinate is kinder on your stomach than oxide. Blood levels level off at about 300 to 400 mg.

Studied for: Sleep

What the trials found:

• Older people with insomnia fell asleep about 17 minutes faster. They did not sleep for longer overall, and the trials were small doi:10.1186/s12906-021-03297-z

Watch out for: Loose stools if you take too much. Build up slowly. Magnesium oxide is the worst for this, so swap type if it upsets you.

NAD⁺ (Nicotinamide Riboside)

How much: 250 to 500 mg a day of nicotinamide riboside (NR). Some trials used up to 1 to 2 grams.

Studied for: Sleep

What the trials found:

• In a trial using NMN, a closely related NAD⁺ precursor, people aged 65 to 75 slept better and walked faster over 12 weeks doi:10.1007/s11357-024-01204-1

Watch out for: Well tolerated, even at high doses. Sometimes it causes mild tummy upset or loose stools.

Ashwagandha

How much: 300 to 600 mg a day of a standard root extract. Sleep trials worked from 120 mg a day.

Studied for: Sleep

What the trials found:

• Better sleep, measured with sleep trackers as well as questionnaires. The effect was bigger in people with insomnia doi:10.1016/j.sleep.2020.03.012 doi:10.1016/j.jep.2020.113276

Worth knowing before you start: Ashwagandha can occasionally injure the liver. Stop taking it and speak to a doctor if your skin or the whites of your eyes turn yellow (jaundice), your skin becomes itchy, your urine goes dark or your stools go pale. Health watchdogs have issued safety warnings about this.

Watch out for: Usually mild. The one that matters is liver injury, which is uncommon but real.

L-theanine

How much: About 100 to 200 mg, taken with a small amount of caffeine (40 to 100 mg) for focus. Tea and matcha contain both naturally.

Studied for: Sleep

What the trials found:

• Small, self reported improvements in sleep quality, often in products that mixed it with other ingredients doi:10.1016/j.smrv.2025.102076 doi:10.3390/nu11102362

Watch out for: Very well tolerated. On its own it occasionally caused a mild headache.

Glycine

How much: 3 g about an hour before bed. It tastes sweet and dissolves easily in water.

Studied for: Sleep

What the trials found:

• In small trials, 3 g before bed improved how well people felt they slept and reduced next day tiredness. The trials were linked to the manufacturer and need independent confirmation doi:10.3389/fneur.2012.00061 doi:10.1080/19390211.2026.2726197

Watch out for: Well tolerated at much higher doses than this. At 30 g a day and above, far more than we suggest, glycine made one schizophrenia medicine (clozapine) work less well.

Saffron extract

How much: About 28 to 30 mg a day of a standardised saffron extract. Choose a named extract with authenticity testing: a lot of saffron on sale is adulterated.

Studied for: Sleep

What the trials found:

• Helped people sleep for longer in small trials. Effects on insomnia severity were not clear doi:10.3390/ijerph191811658 doi:10.1016/j.sleep.2021.08.001

Watch out for: Mild stomach upset in some people, with fewer side effects than antidepressants in trials. High doses (grams) are harmful.

Tart cherry

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. Capsules, the closest form to a supplement, showed no benefit.

Studied for: Sleep

What the trials found:

• Capsules did not improve sleep in two trials (no effect found) doi:10.3390/nu16234125 doi:10.1177/02601060221111230

Watch out for: Juices and concentrates add sugar.

Creatine

How much: 3 to 5 grams a day. You can take 20 grams a day for the first 5 to 7 days to fill up faster, but you do not have to.

Studied for: Blood sugar

What the trials found:

• In type 2 diabetes, blood sugar may come down, especially alongside exercise. Low certainty evidence (medical setting) doi:10.2174/1573399817666210712151737

Watch out for: You hold a little water and may gain a small amount of weight. More than about 10 grams a day causes loose stools.

Magnesium

How much: 200 to 400 mg of magnesium a day. Citrate or glycinate is kinder on your stomach than oxide. Blood levels level off at about 300 to 400 mg.

Studied for: Blood sugar, Sugar handling

What the trials found:

• In type 2 diabetes, blood sugar and HbA1c improved, but only after 4 months or more doi:10.1017/S0007114521005201 doi:10.1016/j.phrs.2016.06.019
• People at risk of diabetes handled sugar better after 4 months or more doi:10.3390/nu13114074

Watch out for: Loose stools if you take too much. Build up slowly. Magnesium oxide is the worst for this, so swap type if it upsets you.

NAD⁺ (Nicotinamide Riboside)

How much: 250 to 500 mg a day of nicotinamide riboside (NR). Some trials used up to 1 to 2 grams.

Studied for: Cholesterol

What the trials found:

• Small falls in total cholesterol and blood fats, from low quality evidence doi:10.1055/a-2382-6829

Watch out for: Well tolerated, even at high doses. Sometimes it causes mild tummy upset or loose stools.

Vinegar

How much: 1 to 2 tablespoons (15 to 30 ml) of ordinary vinegar, mixed into water or on food, with your largest starchy meal. Capsules and neutralised powders are unlikely to work.

Studied for: Blood sugar, Sugar handling, Weight and appetite

What the trials found:

• Blunts the blood sugar spike after a starchy meal such as bread, rice or potatoes, when taken with the meal. It did nothing with low sugar meals or pure sugar doi:10.1016/j.diabres.2017.01.021 doi:10.1038/ejcn.2010.89 doi:10.1159/000272133
• Lowers the rise in insulin after a starchy meal doi:10.1016/j.diabres.2017.01.021
• A small drop in weight and waist size over 12 weeks at 30 ml a day, in people carrying extra weight. Partly because it can make you feel a bit sick doi:10.3390/nu17183000 doi:10.1271/bbb.90231

Watch out for: Can make you feel sick, sting your throat and wear down tooth enamel. Always water it down and rinse your mouth after.

Green tea

How much: 2 to 4 cups of brewed green tea or matcha a day. If you use an extract, keep to 300 mg EGCG a day or less, always with food.

Studied for: Cholesterol, Fatty liver

What the trials found:

• Lowers LDL cholesterol by about 3%. Real, but small doi:10.1186/s12937-020-00557-5
• In people with fatty liver, liver test results improved. In healthy people they slightly worsened (medical setting) doi:10.1002/ptr.6130

Worth knowing before you start: Strong green tea extract can harm the liver. In a year-long trial of a high dose, about 1 in 20 women had a liver test problem. Keep to 338 mg EGCG a day or less as capsules, take it with food, and see a doctor if your skin or eyes turn yellow or your urine goes dark. Brewed tea is the gentler option.

Watch out for: Contains caffeine, which can keep you awake. Strong extract can upset liver tests.

Omega-3

How much: 1 to 2 grams of EPA and DHA a day, with a meal. For low mood, choose one that is mostly EPA.

Studied for: Cholesterol

What the trials found:

• Lowers blood fats (triglycerides). This is the most reliable thing omega-3 does doi:10.1016/j.clinthera.2022.12.009 doi:10.1515/jpem-2018-0409

Watch out for: It can leave a fishy taste or give you heartburn. It thins your blood a little, which matters if you already take blood-thinning medicine.

Vitamin D

How much: 800 to 1,000 IU (20 to 25 micrograms) every day. Daily works better than big monthly doses, and more is not better.

Studied for: Blood sugar

What the trials found:

• In people who already have type 2 diabetes, blood sugar may improve. It did not prevent diabetes (medical setting) doi:10.3967/bes2025.066 doi:10.3390/nu18020357

Watch out for: Very big doses (over 10,000 IU a day) push too much calcium into your blood and urine, which can cause kidney stones.

Coenzyme Q10

How much: 100 to 200 mg a day, with a meal that has some fat in it. Heart failure trials used 100 mg three times a day.

Studied for: Cholesterol

What the trials found:

• Lowers lipoprotein(a), a type of cholesterol, especially when it is high doi:10.1016/j.phrs.2016.01.030

Watch out for: Well tolerated. Sometimes it causes mild tummy upset.

Zinc

How much: 10 to 25 mg a day, with food. Do not go above 40 mg a day from all sources. For colds, only slow-dissolving lozenges have worked.

Studied for: Blood sugar, Sugar handling, Cholesterol

What the trials found:

• Improves blood sugar in type 2 diabetes and pre-diabetes doi:10.1093/ajcn/nqz041 doi:10.1017/S0007114522002616
• Helps your body handle sugar better in type 2 diabetes and pre-diabetes doi:10.1093/ajcn/nqz041
• Improves cholesterol in type 2 diabetes. In healthy people it may lower good cholesterol, so trials disagree doi:10.1016/j.advnut.2023.08.006

Watch out for: Makes you feel sick on an empty stomach. Too much for too long blocks copper, which can cause anaemia and nerve problems.

Taurine

How much: 1.5 to 3 grams a day. The blood sugar effect needed 3 grams. For exercise, trials used 1 to 6 grams 1 to 2 hours before.

Studied for: Blood sugar, Sugar handling, Cholesterol

What the trials found:

• Lowers blood sugar, with a clear step up in benefit at 3 grams a day doi:10.1038/s41387-024-00289-z doi:10.3390/nu17010055
• Helps your body handle sugar at 3 grams a day doi:10.1038/s41387-024-00289-z
• Lowers blood fats and total cholesterol at 3 grams a day doi:10.1038/s41387-024-00289-z doi:10.1007/s00726-003-0059-z

Watch out for: Very well tolerated at normal doses.

Alpha-lipoic acid

How much: 600 mg a day. Side effects rise above this with no extra benefit. Weight trials used 1,800 mg.

Studied for: Sugar handling, Weight and appetite

What the trials found:

• May help your body handle sugar, but trials disagree doi:10.1016/j.nut.2020.111041 doi:10.1016/j.metabol.2018.07.002
• A small weight loss, but only at 1,800 mg a day for 20 weeks. 1,200 mg did not work doi:10.1016/j.amjmed.2010.08.005

Watch out for: Sometimes upsets your stomach. The R form seems gentler than the mixed form. It can lower the iron you absorb.

Vitamin C

How much: 200 to 500 mg a day. Avoid big doses for long stretches.

Studied for: Blood sugar, Cholesterol

What the trials found:

• In type 2 diabetes, blood sugar improved at 1,000 mg a day for 12 weeks or more doi:10.1016/j.dsx.2023.102824
• Improves cholesterol in people with diabetes or who are low in vitamin C doi:10.1016/j.clnu.2015.05.021

Watch out for: Upsets your stomach at high doses. Big doses for a long time raise your kidney stone risk.

Plant sterols and stanols

How much: 1.5 to 3 g a day, taken with a main meal. Usually eaten in fortified spreads, yoghurts or drinks. Stanols are the better choice.

Studied for: Cholesterol

What the trials found:

• Lowers LDL cholesterol by about 8 to 12% (around 0.3 mmol/L) at 2 to 3 g a day. This is high quality evidence, and it adds to the effect of a statin doi:10.1016/j.clnu.2026.106698 doi:10.1017/S0007114514000750 doi:10.1080/07315724.2009.10719784

Watch out for: Well tolerated. It slightly lowers blood levels of carotenoids from fruit and vegetables, so eat plenty of them.

Oat beta-glucan

How much: 3 g of oat beta-glucan a day, ideally spread across meals. Oats and oat bran are good food sources.

Studied for: Blood sugar, Cholesterol

What the trials found:

• Lowers the rise in blood sugar after a meal when it is eaten with that meal. Extracts did not improve fasting blood sugar over weeks doi:10.1038/s41430-021-00875-9 doi:10.1039/c5fo01364j
• Lowers LDL cholesterol by about 0.2 to 0.27 mmol/L at 3 g a day, more when cholesterol starts higher doi:10.3945/ajcn.114.086108 doi:10.1017/S000711451600341X doi:10.3390/nu14102043

Watch out for: Wind and bloating in the first couple of weeks, which settle. Start with a smaller amount and drink plenty of fluid.

Psyllium husk

How much: About 7 to 10 g a day, each dose stirred into a full glass of water (at least 250 mL) and drunk straight away. Not just before bed.

Studied for: Blood sugar, Cholesterol

What the trials found:

• In type 2 diabetes it lowered fasting blood sugar and HbA1c. It made no difference when blood sugar was normal doi:10.3945/ajcn.115.106989 doi:10.1186/s12902-024-01608-2
• Lowers LDL cholesterol by about 0.3 mmol/L at around 10 g a day, and the effect held over six months doi:10.1093/ajcn/nqy115 doi:10.1038/ejcn.2008.49

Watch out for: Wind and bloating at first. Take it with plenty of water: very rarely it has caused choking or a blocked bowel when taken with too little. Avoid breathing in the powder, which can irritate the lungs and trigger allergy. Do not take it if you have difficulty swallowing, a narrowed bowel or a past bowel blockage.

Turmeric (curcumin extract)

How much: 500 to 1,000 mg a day of a curcumin extract, with food, for 8 to 12 weeks. Culinary turmeric contains only about 3% curcumin. Avoid products with added black pepper extract (piperine).

Studied for: Blood sugar

What the trials found:

• In people with type 2 diabetes it lowered fasting blood sugar and HbA1c a little (medical setting) doi:10.3390/nu16234177

Worth knowing before you start: Turmeric and curcumin supplements have caused rare but serious liver injury, sometimes with high absorption or black pepper products. Stop and see a doctor if your skin or eyes turn yellow, your skin itches, your urine goes dark or your stools go pale.

Watch out for: Mild stomach upset in some people. Take it with food. Avoid it if you have gallstones, as it makes the gallbladder contract.

Panax ginseng

Information only. The evidence is too uncertain to suggest it.

How much: Trial doses ranged from 0.2 g to 20 g a day, and the active ingredients in shop products varied by up to 36 times, so there is no reliable dose.

Studied for: Blood sugar

What the trials found:

• Lowered fasting blood sugar slightly (about 0.3 mmol/L), with no change in HbA1c (information only) doi:10.1371/journal.pone.0107391

Watch out for: Poor sleep, headache and a faster heartbeat. Take it in the morning.

Resveratrol

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. Trials used up to 1 g a day; GB rules cap supplements at 150 mg a day.

Studied for: Blood sugar, Cholesterol

What the trials found:

• No benefit for blood sugar or HbA1c in type 2 diabetes, in a review of 10 meta-analyses (no effect found) doi:10.1007/s40199-026-00609-x
• No change in cholesterol across 21 trials (no effect found) doi:10.1016/j.phrs.2017.12.033

Watch out for: At high doses it slows the liver enzymes that break down many medicines. In older men starting exercise it blunted the gains in fitness.

Astaxanthin

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. GB rules cap supplements at 8 mg a day.

Studied for: Blood sugar

What the trials found:

• No effect on blood sugar, cholesterol, weight or blood pressure (no effect found) doi:10.1016/j.phrs.2020.105113

Watch out for: Mostly improves blood markers of oxidative stress rather than anything you would feel.

Tart cherry

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. Capsules, the closest form to a supplement, showed no benefit.

Studied for: Blood sugar

What the trials found:

• No meaningful effect on blood sugar or weight (no effect found) doi:10.1016/j.dsx.2024.103026

Watch out for: Juices and concentrates add sugar.

L-citrulline

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. Caffeine and beetroot do the pre-exercise job better.

Studied for: Weight and appetite

What the trials found:

• No effect on weight, body fat or muscle across 21 trials (no effect found) doi:10.3390/nu17193126

Watch out for: Well tolerated; mild stomach upset at high doses.

Berberine

How much: 500 mg two or three times a day with meals. Your body absorbs it poorly, so the type you buy matters.

Studied for: Blood sugar, Sugar handling, Weight and appetite, Cholesterol, Fatty liver

What the trials found:

• Lowers blood sugar and HbA1c in type 2 diabetes and pre-diabetes doi:10.1016/j.clinthera.2023.10.019 doi:10.1016/j.tjnut.2023.08.016 doi:10.1016/j.metabol.2008.01.013
• Helps your body handle sugar, and cleared metabolic syndrome in some people doi:10.1089/met.2012.0183
• Small falls in BMI and waist size were seen in some blood sugar trials doi:10.1016/j.clinthera.2023.10.019
• Lowers total cholesterol, LDL and blood fats, working in a different way to statins doi:10.1038/nm1135 doi:10.1155/2021/2074610
• In fatty liver, liver tests and liver fat improved in one review, but results vary (medical setting) doi:10.1186/s12967-024-05011-2

Watch out for: Constipation or loose stools are common. It adds to the sugar-lowering effect of diabetes medicine.

Magnesium

How much: 200 to 400 mg of magnesium a day. Citrate or glycinate is kinder on your stomach than oxide. Blood levels level off at about 300 to 400 mg.

Studied for: Blood pressure

What the trials found:

• Brings blood pressure down by 2 to 3 points, but mainly in people who are low in magnesium or whose blood pressure is not under control. If your levels are normal it does very little doi:10.1161/HYPERTENSIONAHA.125.25129 doi:10.3390/nu13010195

Watch out for: Loose stools if you take too much. Build up slowly. Magnesium oxide is the worst for this, so swap type if it upsets you.

Green tea

How much: 2 to 4 cups of brewed green tea or matcha a day. If you use an extract, keep to 300 mg EGCG a day or less, always with food.

Studied for: Blood pressure, Heart attacks and strokes

What the trials found:

• Brings blood pressure down by 1 to 2 points, which is very small doi:10.1080/08037051.2025.2517122
• People who drink green tea regularly have fewer strokes. This comes from studies of tea drinkers, not extract capsules, and cannot prove cause (medical setting) doi:10.1016/j.nut.2022.111936

Worth knowing before you start: Strong green tea extract can harm the liver. In a year-long trial of a high dose, about 1 in 20 women had a liver test problem. Keep to 338 mg EGCG a day or less as capsules, take it with food, and see a doctor if your skin or eyes turn yellow or your urine goes dark. Brewed tea is the gentler option.

Watch out for: Contains caffeine, which can keep you awake. Strong extract can upset liver tests.

Omega-3

How much: 1 to 2 grams of EPA and DHA a day, with a meal. For low mood, choose one that is mostly EPA.

Studied for: Heart risk, Blood pressure, Heart attacks and strokes, Cancer risk

What the trials found:

• A small drop in heart problems in people without heart disease, when the big VITAL trial was combined with earlier trials doi:10.1016/j.ajcnut.2025.02.028
• Brings blood pressure down when it is taken alongside regular exercise doi:10.1016/j.clnesp.2025.01.022
• May mean fewer heart attacks and strokes in people who already have heart disease. The largest review did not agree, possibly because of the mix of EPA and DHA used doi:10.1039/d3fo02522e doi:10.1001/jamacardio.2017.5205
• During chemotherapy it helped people keep their weight and nutrition up, and reduced nerve damage from the treatment (medical setting) doi:10.1080/10408398.2021.1984199 doi:10.1093/nutrit/nuz054

Watch out for: It can leave a fishy taste or give you heartburn. It thins your blood a little, which matters if you already take blood-thinning medicine.

Vitamin D

How much: 800 to 1,000 IU (20 to 25 micrograms) every day. Daily works better than big monthly doses, and more is not better.

Studied for: Heart attacks and strokes, Falls and broken bones, Bone strength

What the trials found:

• May slightly lower heart attacks and strokes, mostly in people already on heart medicines. The result only just missed being certain doi:10.1136/bmj-2023-075230
• Older people taking 800 to 1,000 IU every day had fewer falls. Bigger doses, or big doses taken once a month, did not help and may make falls more likely doi:10.1186/s12877-024-05009-x doi:10.1002/jcsm.12759
• Taken with calcium, it slightly cuts broken bones, mainly in care home residents. Vitamin D on its own did not doi:10.1136/bmj-2025-088050 doi:10.1210/clinem/dgab742

Watch out for: Very big doses (over 10,000 IU a day) push too much calcium into your blood and urine, which can cause kidney stones.

Coenzyme Q10

How much: 100 to 200 mg a day, with a meal that has some fat in it. Heart failure trials used 100 mg three times a day.

Studied for: Blood pressure, Blood vessels, Heart attacks and strokes

What the trials found:

• May bring blood pressure down a little in people with heart or metabolic disease, but trials disagree doi:10.1093/advances/nmac100
• Helps blood vessels widen properly doi:10.1007/s40292-024-00630-8
• Added to standard heart failure treatment, it meant fewer deaths and fewer hospital stays doi:10.1002/14651858.CD008684.pub3 doi:10.1186/s12872-024-04232-z

Watch out for: Well tolerated. Sometimes it causes mild tummy upset.

Taurine

How much: 1.5 to 3 grams a day. The blood sugar effect needed 3 grams. For exercise, trials used 1 to 6 grams 1 to 2 hours before.

Studied for: Blood pressure, Heart attacks and strokes

What the trials found:

• Brings blood pressure down, mostly in people whose blood pressure is already raised doi:10.1161/HYPERTENSIONAHA.115.06624 doi:10.1038/s41387-024-00289-z
• In heart failure, symptoms and heart pumping improved in older small trials (medical setting) doi:10.1186/s12937-024-00995-5

Watch out for: Very well tolerated at normal doses.

Alpha-lipoic acid

How much: 600 mg a day. Side effects rise above this with no extra benefit. Weight trials used 1,800 mg.

Studied for: Blood vessels

What the trials found:

• Helps the lining of blood vessels work better. One of the most consistent ALA findings doi:10.1080/10408398.2020.1861425 doi:10.1155/2015/474561

Watch out for: Sometimes upsets your stomach. The R form seems gentler than the mixed form. It can lower the iron you absorb.

Vitamin C

How much: 200 to 500 mg a day. Avoid big doses for long stretches.

Studied for: Blood pressure, Blood vessels

What the trials found:

• Brings blood pressure down a little, most in people with high blood pressure or diabetes doi:10.1039/d5fo03679h doi:10.3945/ajcn.111.027995
• Helps blood vessels work better, most in people at higher heart risk doi:10.1016/j.atherosclerosis.2014.04.004

Watch out for: Upsets your stomach at high doses. Big doses for a long time raise your kidney stone risk.

Lutein and Zeaxanthin

How much: 10 mg lutein plus 2 mg zeaxanthin a day, with a meal that has some fat in it. Below 5 mg does nothing.

Studied for: Blood vessels

What the trials found:

• Slowed thickening of the neck artery walls in one trial doi:10.1017/S0007114513002730

Watch out for: Very well tolerated. Very high amounts can turn your skin slightly yellow, which is harmless.

Beetroot (nitrate)

How much: 400 to 500 mg of nitrate, about 2 to 3 hours before exercise, from beetroot juice or a concentrated beetroot extract. For occasional use around training, not every day.

Studied for: Blood pressure

What the trials found:

• Lowers blood pressure measured in the clinic by about 4 to 5 points, most in older people whose pressure is raised. Readings over 24 hours did not change in the pooled trials (medical setting) doi:10.1016/j.numecd.2024.06.009 doi:10.1161/HYPERTENSIONAHA.114.04675

Watch out for: It can turn your urine and stools pink or red, which is harmless but can be mistaken for blood. It can also lower blood pressure a little more if you already take medicines that do this.

Vitamin K2 (MK-7)

How much: 180 to 360 micrograms a day of the MK-7 form, with food.

Studied for: Blood vessels, Bone strength

What the trials found:

• Slowed the build up of calcium in the heart's arteries over two years in people with coronary artery disease, and in a larger trial (with vitamin D) of people with heavy calcification. No trial has yet shown fewer heart attacks doi:10.1001/jamacardio.2026.1279 doi:10.1161/CIRCULATIONAHA.126.082363
• A small gain in spine bone density, mostly with a prescription form used in Japan. It did not reduce broken bones doi:10.3389/fpubh.2022.979649 doi:10.1007/s00774-022-01342-6

Watch out for: Side effects were no different from placebo at these doses.

Cocoa flavanols

How much: 500 mg of cocoa flavanols a day from a standardised cocoa extract (the dose in the largest trial). Chocolate is not a practical source.

Studied for: Heart risk, Blood pressure

What the trials found:

• Possibly fewer deaths from heart disease. In a trial of 21,442 older adults without previous heart attack or stroke, the main heart outcome just missed (HR 0.90, 0.78 to 1.02), while heart deaths fell by about a quarter (HR 0.73, 0.54 to 0.98), a secondary result doi:10.1093/ajcn/nqac055
• Lowers blood pressure slightly, by about 2 points overall and about 4 points in people with high blood pressure, and helps blood vessels widen doi:10.1002/14651858.CD008893.pub3 doi:10.1093/eurjpc/zwaf173

Watch out for: Very well tolerated; a little more nausea than placebo. The extract contains a small amount of caffeine. Choose a product tested for cadmium and lead.

Resveratrol

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. Trials used up to 1 g a day; GB rules cap supplements at 150 mg a day.

Studied for: Blood pressure, Bone strength

What the trials found:

• No effect on blood pressure or inflammation markers across 10 trials (no effect found) doi:10.1016/j.ijcard.2015.04.008
• No effect on bone density across 10 trials (no effect found) doi:10.1186/s12906-021-03381-4

Watch out for: At high doses it slows the liver enzymes that break down many medicines. In older men starting exercise it blunted the gains in fitness.

Tart cherry

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. Capsules, the closest form to a supplement, showed no benefit.

Studied for: Blood pressure

What the trials found:

• No change in blood pressure across 7 trials (no effect found) doi:10.1016/j.dsx.2022.102409

Watch out for: Juices and concentrates add sugar.

Berberine

How much: 500 mg two or three times a day with meals. Your body absorbs it poorly, so the type you buy matters.

Studied for: Cancer risk

What the trials found:

• In a large trial, people who had bowel polyps removed were less likely to grow new ones doi:10.1016/S2468-1253(19)30409-1

Watch out for: Constipation or loose stools are common. It adds to the sugar-lowering effect of diabetes medicine.

Magnesium

How much: 200 to 400 mg of magnesium a day. Citrate or glycinate is kinder on your stomach than oxide. Blood levels level off at about 300 to 400 mg.

Studied for: Inflammation

What the trials found:

• Lowers the inflammation marker CRP, but only in people whose CRP is already raised doi:10.3390/nu14030679 doi:10.2174/1381612823666170525153605

Watch out for: Loose stools if you take too much. Build up slowly. Magnesium oxide is the worst for this, so swap type if it upsets you.

NAD⁺ (Nicotinamide Riboside)

How much: 250 to 500 mg a day of nicotinamide riboside (NR). Some trials used up to 1 to 2 grams.

Studied for: Inflammation

What the trials found:

• Lowered inflammation markers in the blood of older men, in a small trial doi:10.1016/j.celrep.2019.07.043

Watch out for: Well tolerated, even at high doses. Sometimes it causes mild tummy upset or loose stools.

Omega-3

How much: 1 to 2 grams of EPA and DHA a day, with a meal. For low mood, choose one that is mostly EPA.

Studied for: Inflammation

What the trials found:

• In people with heart disease, it lowered inflammation markers and helped blood vessel lining work better (medical setting) doi:10.14715/cmb/2024.70.6.26

Watch out for: It can leave a fishy taste or give you heartburn. It thins your blood a little, which matters if you already take blood-thinning medicine.

Coenzyme Q10

How much: 100 to 200 mg a day, with a meal that has some fat in it. Heart failure trials used 100 mg three times a day.

Studied for: Recovery after exercise

What the trials found:

• Less muscle damage and strain on the body after hard exercise doi:10.1016/j.clnesp.2024.01.015 doi:10.3390/nu15183990

Watch out for: Well tolerated. Sometimes it causes mild tummy upset.

Ashwagandha

How much: 300 to 600 mg a day of a standard root extract. Sleep trials worked from 120 mg a day.

Studied for: Recovery after exercise

What the trials found:

• Less muscle soreness and better recovery in athletes, from small trials doi:10.3390/nu18020230 doi:10.1002/ejsc.12265

Worth knowing before you start: Ashwagandha can occasionally injure the liver. Stop taking it and speak to a doctor if your skin or the whites of your eyes turn yellow (jaundice), your skin becomes itchy, your urine goes dark or your stools go pale. Health watchdogs have issued safety warnings about this.

Watch out for: Usually mild. The one that matters is liver injury, which is uncommon but real.

Taurine

How much: 1.5 to 3 grams a day. The blood sugar effect needed 3 grams. For exercise, trials used 1 to 6 grams 1 to 2 hours before.

Studied for: Inflammation

What the trials found:

• With exercise training, inflammation markers fell doi:10.1007/s00726-021-03041-4

Watch out for: Very well tolerated at normal doses.

Alpha-lipoic acid

How much: 600 mg a day. Side effects rise above this with no extra benefit. Weight trials used 1,800 mg.

Studied for: Inflammation

What the trials found:

• Lowers inflammation markers in your blood doi:10.1016/j.clnesp.2019.03.015

Watch out for: Sometimes upsets your stomach. The R form seems gentler than the mixed form. It can lower the iron you absorb.

Vitamin C

How much: 200 to 500 mg a day. Avoid big doses for long stretches.

Studied for: Recovery after exercise

What the trials found:

• Supports healing after injury, and helped prevent long-term pain after wrist fractures doi:10.2106/JBJS.F.01147 doi:10.1016/j.otsr.2016.12.021

Watch out for: Upsets your stomach at high doses. Big doses for a long time raise your kidney stone risk.

Lutein and Zeaxanthin

How much: 10 mg lutein plus 2 mg zeaxanthin a day, with a meal that has some fat in it. Below 5 mg does nothing.

Studied for: Inflammation

What the trials found:

• Lowers inflammation markers, but not in people who are already well nourished doi:10.1016/j.atherosclerosis.2013.01.021

Watch out for: Very well tolerated. Very high amounts can turn your skin slightly yellow, which is harmless.

Collagen peptides

How much: 10 to 15 g, taken with vitamin C (about 50 mg) 30 to 60 minutes before training or rehab exercises.

Studied for: Recovery after exercise

What the trials found:

• Taken before exercise it raised markers of collagen building, and in a small tendon rehab trial people improved faster. No trial has shown fewer injuries yet doi:10.3945/ajcn.116.138594 doi:10.3390/nu11010076 doi:10.3389/fmed.2026.1891011

Watch out for: Occasional bloating or fullness, as with any protein powder. It is made from animal or fish collagen.

Tart cherry

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. Capsules, the closest form to a supplement, showed no benefit.

Studied for: Recovery after exercise

What the trials found:

• No effect on muscle damage or inflammation markers after exercise; recovery reviews disagree (no effect found) doi:10.1123/ijsnem.2020-0145 doi:10.1186/s40798-026-00993-3

Watch out for: Juices and concentrates add sugar.

L-citrulline

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. Caffeine and beetroot do the pre-exercise job better.

Studied for: Recovery after exercise

What the trials found:

• No effect on inflammation or oxidative stress after exercise (no effect found) doi:10.3390/nu15081995

Watch out for: Well tolerated; mild stomach upset at high doses.

Berberine

How much: 500 mg two or three times a day with meals. Your body absorbs it poorly, so the type you buy matters.

Studied for: Inflammation

What the trials found:

• Lowers inflammation markers in metabolic syndrome doi:10.1007/s10787-022-00976-2

Watch out for: Constipation or loose stools are common. It adds to the sugar-lowering effect of diabetes medicine.

Creatine

How much: 3 to 5 grams a day. You can take 20 grams a day for the first 5 to 7 days to fill up faster, but you do not have to.

Studied for: Strength and muscle

What the trials found:

• More strength and power, better sprints and jumps, and about 1 kg more lean muscle, when you also do resistance training. One of the best proven supplement findings there is, though the gains are modest doi:10.3390/nu17172748 doi:10.1007/s40279-016-0571-4 doi:10.1080/15502783.2024.2380058

Watch out for: You hold a little water and may gain a small amount of weight. More than about 10 grams a day causes loose stools.

NAD⁺ (Nicotinamide Riboside)

How much: 250 to 500 mg a day of nicotinamide riboside (NR). Some trials used up to 1 to 2 grams.

Studied for: Endurance

What the trials found:

• People with poor blood flow in their legs walked 17 to 31 metres further in a 6 minute walk test doi:10.1038/s41467-024-49092-5

Watch out for: Well tolerated, even at high doses. Sometimes it causes mild tummy upset or loose stools.

Omega-3

How much: 1 to 2 grams of EPA and DHA a day, with a meal. For low mood, choose one that is mostly EPA.

Studied for: Strength and muscle

What the trials found:

• May add a little to the strength you gain from exercise, but trials disagree doi:10.1016/j.clnu.2024.08.004

Watch out for: It can leave a fishy taste or give you heartburn. It thins your blood a little, which matters if you already take blood-thinning medicine.

Ashwagandha

How much: 300 to 600 mg a day of a standard root extract. Sleep trials worked from 120 mg a day.

Studied for: Strength and muscle, Endurance

What the trials found:

• Bigger, stronger muscles, but only when you also lift weights doi:10.3390/nu10111807 doi:10.1186/s12970-015-0104-9
• Fitter heart and lungs (VO2 max) in people who train doi:10.1016/j.jep.2021.113929 doi:10.12688/f1000research.130932.2

Worth knowing before you start: Ashwagandha can occasionally injure the liver. Stop taking it and speak to a doctor if your skin or the whites of your eyes turn yellow (jaundice), your skin becomes itchy, your urine goes dark or your stools go pale. Health watchdogs have issued safety warnings about this.

Watch out for: Usually mild. The one that matters is liver injury, which is uncommon but real.

Taurine

How much: 1.5 to 3 grams a day. The blood sugar effect needed 3 grams. For exercise, trials used 1 to 6 grams 1 to 2 hours before.

Studied for: Strength and muscle, Endurance

What the trials found:

• More sprint power, but only at 4 grams or more taken before exercise doi:10.1080/15438627.2023.2198129
• Helped some people exercise for longer, and in the heat. Trials disagree, and 1 gram worked as well as 6 doi:10.1007/s40279-018-0896-2 doi:10.1007/s00421-024-05478-3

Watch out for: Very well tolerated at normal doses.

Caffeine

How much: About 3 mg per kg of body weight (around 200 mg for most adults) about an hour before exercise. Count your coffee, tea and energy drinks, and keep the day's total under 400 mg.

Studied for: Strength and muscle, Endurance

What the trials found:

• A small gain in maximal strength and power, mainly in the upper body. Leg strength did not clearly change doi:10.1186/s12970-018-0216-0 doi:10.3390/ijerph18115773
• Lets you keep going for longer and finish timed efforts a little faster. This works in trained athletes as well as recreational exercisers doi:10.1136/bjsports-2018-100278 doi:10.1007/s40279-018-0939-8 doi:10.3390/nu15010148

Worth knowing before you start: Take it in the morning or early afternoon. A typical pre-exercise dose cut sleep when taken within about 13 hours of bed. High doses have also been linked with worse anxiety and with panic attacks in people who have panic disorder.

Watch out for: Poor sleep, jitteriness, a faster heartbeat and an upset stomach, all more likely at higher doses. The contraceptive pill and some antibiotics make caffeine last longer, so take it earlier in the day if you use them. At moderate doses it does not dehydrate regular coffee drinkers.

Beta-alanine

How much: 3.2 to 6.4 g a day, split into smaller doses of about 0.8 to 1.6 g with meals, for at least 4 weeks. It works by building up slowly, so it is a daily supplement, not a pre-workout.

Studied for: Strength and muscle, Endurance

What the trials found:

• May help strength and power training when the daily amount is split into several small doses. The studies are small and do not all agree doi:10.1080/15502783.2025.2566368 doi:10.1186/s12970-015-0090-y
• Helps you keep going during hard efforts lasting about 1 to 10 minutes, such as intervals, rowing or middle distance running. The typical gain is about 3%, after about a month of daily use doi:10.1007/s00726-011-1200-z doi:10.1136/bjsports-2016-096396 doi:10.1123/ijsnem.2024-0027

Watch out for: A harmless pins and needles or tingling feeling in the skin, usually within an hour of a dose and gone within about an hour. It comes from a skin nerve receptor, not nerve damage, and is less likely with smaller split doses or slow release forms.

Beetroot (nitrate)

How much: 400 to 500 mg of nitrate, about 2 to 3 hours before exercise, from beetroot juice or a concentrated beetroot extract. For occasional use around training, not every day.

Studied for: Endurance

What the trials found:

• A small boost to endurance in recreational exercisers, partly because muscles use less oxygen for the same work. It did not help well trained athletes doi:10.1007/s40279-025-02194-6 doi:10.1249/MSS.0000000000002363 doi:10.1016/j.niox.2016.01.001

Watch out for: It can turn your urine and stools pink or red, which is harmless but can be mistaken for blood. It can also lower blood pressure a little more if you already take medicines that do this.

HMB (beta-hydroxy beta-methylbutyrate)

How much: 3 g a day of calcium HMB, with food. Benefits were seen in older adults, mainly those not doing regular exercise.

Studied for: Strength and muscle

What the trials found:

• In young people who train it made no difference to muscle or strength (no effect found) doi:10.3390/nu12051523

Watch out for: Well tolerated, with safety data up to a year. Calcium HMB contains calcium (about 410 mg in 3 g).

Astaxanthin

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. GB rules cap supplements at 8 mg a day.

Studied for: Endurance

What the trials found:

• No effect on fitness, time trials or power across 24 trials (no effect found) doi:10.3390/nu18101570

Watch out for: Mostly improves blood markers of oxidative stress rather than anything you would feel.

L-citrulline

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. Caffeine and beetroot do the pre-exercise job better.

Studied for: Endurance

What the trials found:

• No effect on endurance, time to exhaustion or fitness across three meta-analyses (no effect found) doi:10.1080/15502783.2023.2209056 doi:10.3390/nu14173479

Watch out for: Well tolerated; mild stomach upset at high doses.

Rhodiola rosea

How much: 200 to 400 mg a day of a standard extract. For exercise, trials used about 3 mg per kg of body weight an hour before.

Studied for: Strength and muscle, Endurance

What the trials found:

• Improved sprint and strength performance in small trials doi:10.1080/02640414.2018.1538028 doi:10.3390/nu17233736
• Made effort feel easier and improved endurance doi:10.1519/JSC.0b013e31825d9799 doi:10.1123/ijsnem.14.3.298

Watch out for: Usually mild: a dry mouth and sometimes feeling dizzy.

Creatine

How much: 3 to 5 grams a day. You can take 20 grams a day for the first 5 to 7 days to fill up faster, but you do not have to.

Studied for: Memory and focus

What the trials found:

• Better memory, mostly in older adults and vegetarians, and when short of sleep. No benefit in young healthy people doi:10.1093/nutrit/nuac064 doi:10.1016/j.exger.2018.04.013

Watch out for: You hold a little water and may gain a small amount of weight. More than about 10 grams a day causes loose stools.

Green tea

How much: 2 to 4 cups of brewed green tea or matcha a day. If you use an extract, keep to 300 mg EGCG a day or less, always with food.

Studied for: Memory and focus

What the trials found:

• Sharper attention and memory when the caffeine and L-theanine in green tea are taken together. Decaffeinated extract does not do this doi:10.1016/j.phymed.2017.07.008

Worth knowing before you start: Strong green tea extract can harm the liver. In a year-long trial of a high dose, about 1 in 20 women had a liver test problem. Keep to 338 mg EGCG a day or less as capsules, take it with food, and see a doctor if your skin or eyes turn yellow or your urine goes dark. Brewed tea is the gentler option.

Watch out for: Contains caffeine, which can keep you awake. Strong extract can upset liver tests.

Coenzyme Q10

How much: 100 to 200 mg a day, with a meal that has some fat in it. Heart failure trials used 100 mg three times a day.

Studied for: Tiredness

What the trials found:

• Less tiredness, most clearly in fibromyalgia and in people tired from statins doi:10.1016/j.ctim.2019.01.022

Watch out for: Well tolerated. Sometimes it causes mild tummy upset.

Ashwagandha

How much: 300 to 600 mg a day of a standard root extract. Sleep trials worked from 120 mg a day.

Studied for: Memory and focus, Tiredness

What the trials found:

• Better attention, reaction time and memory in small trials doi:10.1080/19390211.2017.1284970 doi:10.3390/nu16121813
• Less tension and tiredness on mood questionnaires doi:10.25122/jml-2025-0172 doi:10.3390/nu16121813

Worth knowing before you start: Ashwagandha can occasionally injure the liver. Stop taking it and speak to a doctor if your skin or the whites of your eyes turn yellow (jaundice), your skin becomes itchy, your urine goes dark or your stools go pale. Health watchdogs have issued safety warnings about this.

Watch out for: Usually mild. The one that matters is liver injury, which is uncommon but real.

Vitamin C

How much: 200 to 500 mg a day. Avoid big doses for long stretches.

Studied for: Tiredness

What the trials found:

• More energy, motivation and attention in people who were low in vitamin C doi:10.1007/s00394-021-02656-3

Watch out for: Upsets your stomach at high doses. Big doses for a long time raise your kidney stone risk.

PQQ (Pyrroloquinoline quinone)

How much: 20 mg a day. Almost every trial used this amount.

Studied for: Memory and focus

What the trials found:

• Better memory and attention in adults over 40, in three small trials, all run or paid for by the makers doi:10.1080/07315724.2021.1962770 doi:10.1039/d2fo01515c

Watch out for: No safety worries so far, but only a few hundred people have been studied in short trials.

Lutein and Zeaxanthin

How much: 10 mg lutein plus 2 mg zeaxanthin a day, with a meal that has some fat in it. Below 5 mg does nothing.

Studied for: Memory and focus

What the trials found:

• Faster visual processing and hand-eye reactions, even in young healthy adults doi:10.1371/journal.pone.0108178

Watch out for: Very well tolerated. Very high amounts can turn your skin slightly yellow, which is harmless.

Caffeine

How much: About 3 mg per kg of body weight (around 200 mg for most adults) about an hour before exercise. Count your coffee, tea and energy drinks, and keep the day's total under 400 mg.

Studied for: Tiredness

What the trials found:

• Sharper attention, alertness and reaction speed for a few hours doi:10.3390/nu13030868 doi:10.1186/s12970-020-00383-4

Worth knowing before you start: Take it in the morning or early afternoon. A typical pre-exercise dose cut sleep when taken within about 13 hours of bed. High doses have also been linked with worse anxiety and with panic attacks in people who have panic disorder.

Watch out for: Poor sleep, jitteriness, a faster heartbeat and an upset stomach, all more likely at higher doses. The contraceptive pill and some antibiotics make caffeine last longer, so take it earlier in the day if you use them. At moderate doses it does not dehydrate regular coffee drinkers.

Vitamin B12

How much: Only if your B12 is low or you eat a vegan or vegetarian diet. For a vegan or vegetarian diet, 25 to 100 micrograms a day. To correct a low level, about 1,000 micrograms a day by mouth, as your GP advises.

Studied for: Tiredness

What the trials found:

• Low B12 can cause tiredness, and correcting a low level by mouth works as well as injections for most people. If your level is normal, extra B12 does not give you more energy, mood or memory doi:10.1002/14651858.CD004655.pub3 doi:10.3389/fphar.2025.1602976 doi:10.3390/nu13030923

Watch out for: Very well tolerated by mouth. Avoid combining it with high dose folic acid if you are older.

L-theanine

How much: About 100 to 200 mg, taken with a small amount of caffeine (40 to 100 mg) for focus. Tea and matcha contain both naturally.

Studied for: Memory and focus

What the trials found:

• Taken with caffeine, it gave small gains in attention and alertness for 1 to 2 hours. Caffeine seems to do much of the work doi:10.1093/nutrit/nuaf054 doi:10.1111/nure.12120 doi:10.1016/j.biopsycho.2007.09.008

Watch out for: Very well tolerated. On its own it occasionally caused a mild headache.

Cocoa flavanols

How much: 500 mg of cocoa flavanols a day from a standardised cocoa extract (the dose in the largest trial). Chocolate is not a practical source.

Studied for: Memory and focus

What the trials found:

• Three trials within the same large study found no benefit for memory or thinking (no effect found) doi:10.1002/alz.12767 doi:10.1073/pnas.2216932120 doi:10.1016/j.ajcnut.2023.10.031

Watch out for: Very well tolerated; a little more nausea than placebo. The extract contains a small amount of caffeine. Choose a product tested for cadmium and lead.

Panax ginseng

Information only. The evidence is too uncertain to suggest it.

How much: Trial doses ranged from 0.2 g to 20 g a day, and the active ingredients in shop products varied by up to 36 times, so there is no reliable dose.

Studied for: Tiredness

What the trials found:

• Small effects on general tiredness in some groups; the overall pooled result was not significant (information only) doi:10.1089/jicm.2022.0532 doi:10.1371/journal.pone.0061271

Watch out for: Poor sleep, headache and a faster heartbeat. Take it in the morning.

Resveratrol

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. Trials used up to 1 g a day; GB rules cap supplements at 150 mg a day.

Studied for: Memory and focus

What the trials found:

• No benefit for memory or thinking in older adults (no effect found) doi:10.20960/nh.04479 doi:10.3389/fphar.2025.1588284

Watch out for: At high doses it slows the liver enzymes that break down many medicines. In older men starting exercise it blunted the gains in fitness.

Astaxanthin

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. GB rules cap supplements at 8 mg a day.

Studied for: Memory and focus

What the trials found:

• No clear benefit for memory or thinking (no effect found) doi:10.1177/10998004241227561

Watch out for: Mostly improves blood markers of oxidative stress rather than anything you would feel.

Rhodiola rosea

How much: 200 to 400 mg a day of a standard extract. For exercise, trials used about 3 mg per kg of body weight an hour before.

Studied for: Memory and focus, Tiredness

What the trials found:

• Better attention when under stress doi:10.1016/j.phymed.2010.08.014
• Less tiredness and better mental performance under stress. This is the best supported rhodiola finding, though not every trial agreed doi:10.1078/094471103321659780 doi:10.1055/s-0028-1088346 doi:10.1186/1472-6882-12-70

Watch out for: Usually mild: a dry mouth and sometimes feeling dizzy.

Magnesium

How much: 200 to 400 mg of magnesium a day. Citrate or glycinate is kinder on your stomach than oxide. Blood levels level off at about 300 to 400 mg.

Studied for: Mood and stress

What the trials found:

• Eased worry in people already prone to it, such as with PMS, but only about half the studies were positive. No study measured stress directly doi:10.3390/nu9050429

Watch out for: Loose stools if you take too much. Build up slowly. Magnesium oxide is the worst for this, so swap type if it upsets you.

NAD⁺ (Nicotinamide Riboside)

How much: 250 to 500 mg a day of nicotinamide riboside (NR). Some trials used up to 1 to 2 grams.

Studied for: Mood and stress

What the trials found:

• Better mood in the same NMN trial, but this is the weakest thing we know about it doi:10.1007/s11357-024-01204-1

Watch out for: Well tolerated, even at high doses. Sometimes it causes mild tummy upset or loose stools.

Green tea

How much: 2 to 4 cups of brewed green tea or matcha a day. If you use an extract, keep to 300 mg EGCG a day or less, always with food.

Studied for: Mood and stress

What the trials found:

• L-theanine, from green tea, may ease stress at 200 to 400 mg a day doi:10.1007/s11130-019-00771-5

Worth knowing before you start: Strong green tea extract can harm the liver. In a year-long trial of a high dose, about 1 in 20 women had a liver test problem. Keep to 338 mg EGCG a day or less as capsules, take it with food, and see a doctor if your skin or eyes turn yellow or your urine goes dark. Brewed tea is the gentler option.

Watch out for: Contains caffeine, which can keep you awake. Strong extract can upset liver tests.

Omega-3

How much: 1 to 2 grams of EPA and DHA a day, with a meal. For low mood, choose one that is mostly EPA.

Studied for: Mood and stress

What the trials found:

• Eases low mood, but only products that are mostly EPA. Mostly-DHA products did not help doi:10.1080/07315724.2009.10719785 doi:10.1186/s12888-020-02656-3

Watch out for: It can leave a fishy taste or give you heartburn. It thins your blood a little, which matters if you already take blood-thinning medicine.

Coenzyme Q10

How much: 100 to 200 mg a day, with a meal that has some fat in it. Heart failure trials used 100 mg three times a day.

Studied for: Mood and stress

What the trials found:

• Eased low mood, mostly in people with another medical condition doi:10.1097/JCP.0000000000002112

Watch out for: Well tolerated. Sometimes it causes mild tummy upset.

Zinc

How much: 10 to 25 mg a day, with food. Do not go above 40 mg a day from all sources. For colds, only slow-dissolving lozenges have worked.

Studied for: Mood and stress

What the trials found:

• Lowered depression scores when taken on its own, though not when added to antidepressants doi:10.1016/j.genhosppsych.2020.08.001

Watch out for: Makes you feel sick on an empty stomach. Too much for too long blocks copper, which can cause anaemia and nerve problems.

Ashwagandha

How much: 300 to 600 mg a day of a standard root extract. Sleep trials worked from 120 mg a day.

Studied for: Mood and stress

What the trials found:

• Less stress and worry. This is the best proven finding for ashwagandha, from more than 11 trials, most lasting 8 to 12 weeks doi:10.1097/MD.0000000000047990 doi:10.1097/MD.0000000000017186 doi:10.2174/1574884715666200413120413

Worth knowing before you start: Ashwagandha can occasionally injure the liver. Stop taking it and speak to a doctor if your skin or the whites of your eyes turn yellow (jaundice), your skin becomes itchy, your urine goes dark or your stools go pale. Health watchdogs have issued safety warnings about this.

Watch out for: Usually mild. The one that matters is liver injury, which is uncommon but real.

Vitamin C

How much: 200 to 500 mg a day. Avoid big doses for long stretches.

Studied for: Mood and stress

What the trials found:

• Better mood and less distress in people who were low in vitamin C doi:10.3945/ajcn.112.056366

Watch out for: Upsets your stomach at high doses. Big doses for a long time raise your kidney stone risk.

L-theanine

How much: About 100 to 200 mg, taken with a small amount of caffeine (40 to 100 mg) for focus. Tea and matcha contain both naturally.

Studied for: Mood and stress

What the trials found:

• On its own, small and short lived reductions in stress in laboratory tests. A larger independent trial in anxiety found no effect doi:10.1007/s11130-019-00771-5 doi:10.1016/j.jpsychires.2018.12.014

Watch out for: Very well tolerated. On its own it occasionally caused a mild headache.

Saffron extract

How much: About 28 to 30 mg a day of a standardised saffron extract. Choose a named extract with authenticity testing: a lot of saffron on sale is adulterated.

Studied for: Mood and stress

What the trials found:

• Eased low mood and worry on self rated questionnaires across many small trials, and did about as well as some antidepressants in small head to head trials. The trials are small and the effect may be overestimated doi:10.1080/1028415X.2025.2602153 doi:10.1093/nutrit/nuae076 doi:10.1016/j.tjnut.2025.05.024

Watch out for: Mild stomach upset in some people, with fewer side effects than antidepressants in trials. High doses (grams) are harmful.

Rhodiola rosea

How much: 200 to 400 mg a day of a standard extract. For exercise, trials used about 3 mg per kg of body weight an hour before.

Studied for: Mood and stress

What the trials found:

• Eased mild to moderate depression with few side effects, and lowered anxiety in mildly anxious people. Trials disagree doi:10.1016/j.phymed.2015.01.010 doi:10.1089/acm.2007.7117

Watch out for: Usually mild: a dry mouth and sometimes feeling dizzy.

Creatine

How much: 3 to 5 grams a day. You can take 20 grams a day for the first 5 to 7 days to fill up faster, but you do not have to.

Studied for: Ageing well

What the trials found:

• Helps older adults hold on to muscle and strength, including getting up from a chair more easily, when they also do resistance training doi:10.1249/MSS.0000000000000220 doi:10.1002/jpen.2607

Watch out for: You hold a little water and may gain a small amount of weight. More than about 10 grams a day causes loose stools.

NAD⁺ (Nicotinamide Riboside)

How much: 250 to 500 mg a day of nicotinamide riboside (NR). Some trials used up to 1 to 2 grams.

Studied for: Ageing well, NAD⁺ levels

What the trials found:

• Lowered blood markers linked to brain ageing in healthy older adults, and helped blood vessel stiffness in a rare premature ageing condition. Early findings only doi:10.1111/acel.13754 doi:10.1111/acel.70093
• Reliably raises the NAD⁺ level in your blood. Whether that makes you healthier is not yet proven doi:10.1038/s41598-019-46120-z doi:10.1016/j.arr.2026.103057

Watch out for: Well tolerated, even at high doses. Sometimes it causes mild tummy upset or loose stools.

Zinc

How much: 10 to 25 mg a day, with food. Do not go above 40 mg a day from all sources. For colds, only slow-dissolving lozenges have worked.

Studied for: Skin

What the trials found:

• Fewer inflamed acne spots doi:10.1111/dth.14252 doi:10.1007/s40257-019-00484-0

Watch out for: Makes you feel sick on an empty stomach. Too much for too long blocks copper, which can cause anaemia and nerve problems.

Vitamin C

How much: 200 to 500 mg a day. Avoid big doses for long stretches.

Studied for: Skin

What the trials found:

• Raises your skin's protection against sun damage, especially with vitamin E doi:10.1159/000350833 doi:10.1016/s0190-9622(98)70537-7

Watch out for: Upsets your stomach at high doses. Big doses for a long time raise your kidney stone risk.

Lutein and Zeaxanthin

How much: 10 mg lutein plus 2 mg zeaxanthin a day, with a meal that has some fat in it. Below 5 mg does nothing.

Studied for: Skin

What the trials found:

• Protected skin cells against UV damage. Not a sunscreen doi:10.1111/bjd.15080

Watch out for: Very well tolerated. Very high amounts can turn your skin slightly yellow, which is harmless.

Beta-alanine

How much: 3.2 to 6.4 g a day, split into smaller doses of about 0.8 to 1.6 g with meals, for at least 4 weeks. It works by building up slowly, so it is a daily supplement, not a pre-workout.

Studied for: Ageing well

What the trials found:

• In small trials of older adults it delayed muscle fatigue, but the largest trial found no gain in everyday physical function (medical setting) doi:10.1186/1550-2783-5-21 doi:10.3390/nu15040923

Watch out for: A harmless pins and needles or tingling feeling in the skin, usually within an hour of a dose and gone within about an hour. It comes from a skin nerve receptor, not nerve damage, and is less likely with smaller split doses or slow release forms.

HMB (beta-hydroxy beta-methylbutyrate)

How much: 3 g a day of calcium HMB, with food. Benefits were seen in older adults, mainly those not doing regular exercise.

Studied for: Ageing well

What the trials found:

• Helped older adults who were not doing structured exercise keep or gain a little muscle and strength. It added little for those who already exercise doi:10.1007/s41999-020-00409-9 doi:10.1016/j.archger.2015.06.020 doi:10.3390/nu11092082

Watch out for: Well tolerated, with safety data up to a year. Calcium HMB contains calcium (about 410 mg in 3 g).

Collagen peptides

How much: 10 to 15 g, taken with vitamin C (about 50 mg) 30 to 60 minutes before training or rehab exercises.

Studied for: Skin

What the trials found:

• Skin benefits disappeared once trials funded by collagen makers were set aside (no effect found) doi:10.1016/j.amjmed.2025.04.034

Watch out for: Occasional bloating or fullness, as with any protein powder. It is made from animal or fish collagen.

Astaxanthin

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. GB rules cap supplements at 8 mg a day.

Studied for: Skin

What the trials found:

• Did not significantly reduce wrinkles (no effect found) doi:10.3390/nu13092917

Watch out for: Mostly improves blood markers of oxidative stress rather than anything you would feel.

Coenzyme Q10

How much: 100 to 200 mg a day, with a meal that has some fat in it. Heart failure trials used 100 mg three times a day.

Studied for: Fertility

What the trials found:

• Better sperm count and movement, and better IVF results in women with a low egg reserve doi:10.1007/s43032-025-01958-9 doi:10.1080/07853890.2024.2389469

Watch out for: Well tolerated. Sometimes it causes mild tummy upset.

Ashwagandha

How much: 300 to 600 mg a day of a standard root extract. Sleep trials worked from 120 mg a day.

Studied for: Fertility

What the trials found:

• In men with unexplained infertility, sperm improved, but at a much higher dose than normal supplements (medical setting) doi:10.1111/and.13041

Worth knowing before you start: Ashwagandha can occasionally injure the liver. Stop taking it and speak to a doctor if your skin or the whites of your eyes turn yellow (jaundice), your skin becomes itchy, your urine goes dark or your stools go pale. Health watchdogs have issued safety warnings about this.

Watch out for: Usually mild. The one that matters is liver injury, which is uncommon but real.

Alpha-lipoic acid

How much: 600 mg a day. Side effects rise above this with no extra benefit. Weight trials used 1,800 mg.

Studied for: Fertility

What the trials found:

• Better sperm in men with fertility problems doi:10.1590/S1677-5538.IBJU.2024.0614

Watch out for: Sometimes upsets your stomach. The R form seems gentler than the mixed form. It can lower the iron you absorb.

NAC (N-acetylcysteine)

How much: 600 to 1,200 mg a day. The chest benefit needs 6 months or more.

Studied for: Fertility

What the trials found:

• Better sperm count, movement and shape in men with fertility problems. Pregnancy rates were not measured doi:10.4081/aiua.2025.13750 doi:10.1111/and.13898

Watch out for: Can make you feel sick or upset your stomach, more so at higher doses. It has a sulphur smell.

Astaxanthin

Studied, but no real benefit found. Listed for information; Vivor does not suggest it.

How much: Not recommended. GB rules cap supplements at 8 mg a day.

Studied for: Fertility

What the trials found:

• No improvement in sperm quality or IVF pregnancy rates (no effect found) doi:10.1038/s41598-026-39963-w doi:10.1186/s13048-024-01472-7

Watch out for: Mostly improves blood markers of oxidative stress rather than anything you would feel.

Berberine

How much: 500 mg two or three times a day with meals. Your body absorbs it poorly, so the type you buy matters.

Studied for: Fertility

What the trials found:

• In PCOS, sugar handling and hormone balance improved, with better IVF results in some trials. Results vary doi:10.1111/cen.12294 doi:10.1016/j.fertnstert.2016.05.022

Watch out for: Constipation or loose stools are common. It adds to the sugar-lowering effect of diabetes medicine.

NAD⁺ (Nicotinamide Riboside)

How much: 250 to 500 mg a day of nicotinamide riboside (NR). Some trials used up to 1 to 2 grams.

Studied for: Breathing

What the trials found:

• In a small trial in COPD, airway inflammation fell and stayed lower after stopping (medical setting) doi:10.1038/s43587-024-00758-1

Watch out for: Well tolerated, even at high doses. Sometimes it causes mild tummy upset or loose stools.

Vitamin D

How much: 800 to 1,000 IU (20 to 25 micrograms) every day. Daily works better than big monthly doses, and more is not better.

Studied for: Autoimmune conditions

What the trials found:

• In a trial of 25,000 adults, fewer people taking it went on to develop autoimmune conditions such as rheumatoid arthritis and psoriasis doi:10.1136/bmj-2021-066452

Watch out for: Very big doses (over 10,000 IU a day) push too much calcium into your blood and urine, which can cause kidney stones.

Zinc

How much: 10 to 25 mg a day, with food. Do not go above 40 mg a day from all sources. For colds, only slow-dissolving lozenges have worked.

Studied for: Fighting infection

What the trials found:

• Colds were shorter when zinc lozenges were sucked slowly from the start. Swallowed tablets did not do this. Daily zinc slightly cut chest and throat infections in adults doi:10.1002/14651858.CD014914.pub2 doi:10.1136/bmjopen-2020-047474

Watch out for: Makes you feel sick on an empty stomach. Too much for too long blocks copper, which can cause anaemia and nerve problems.

Vitamin C

How much: 200 to 500 mg a day. Avoid big doses for long stretches.

Studied for: Fighting infection

What the trials found:

• Taken every day (200 mg or more), colds were shorter and milder. In people under extreme physical stress, such as marathon runners, colds roughly halved doi:10.1002/14651858.CD000980.pub4

Watch out for: Upsets your stomach at high doses. Big doses for a long time raise your kidney stone risk.

NAC (N-acetylcysteine)

How much: 600 to 1,200 mg a day. The chest benefit needs 6 months or more.

Studied for: Breathing

What the trials found:

• Fewer flare-ups in COPD and chronic bronchitis when taken for 6 months or more. It does not improve how well your lungs work, and it is a treatment to agree with your doctor doi:10.1016/j.arbres.2024.03.010 doi:10.1183/16000617.00002215

Watch out for: Can make you feel sick or upset your stomach, more so at higher doses. It has a sulphur smell.

Magnesium

How much: 200 to 400 mg of magnesium a day. Citrate or glycinate is kinder on your stomach than oxide. Blood levels level off at about 300 to 400 mg.

Studied for: Pain

What the trials found:

• Fewer and milder migraines when taken every day to prevent them PubMed 26752497

Watch out for: Loose stools if you take too much. Build up slowly. Magnesium oxide is the worst for this, so swap type if it upsets you.

Omega-3

How much: 1 to 2 grams of EPA and DHA a day, with a meal. For low mood, choose one that is mostly EPA.

Studied for: Pain

What the trials found:

• Less joint pain and morning stiffness, and fewer painkillers needed, in inflammatory joint conditions such as rheumatoid arthritis. It also eased period pain doi:10.1016/j.pain.2007.01.020 doi:10.1002/art.1780370608

Watch out for: It can leave a fishy taste or give you heartburn. It thins your blood a little, which matters if you already take blood-thinning medicine.

Coenzyme Q10

How much: 100 to 200 mg a day, with a meal that has some fat in it. Heart failure trials used 100 mg three times a day.

Studied for: Pain

What the trials found:

• Fewer migraine attacks when taken every day to prevent them doi:10.1136/bmjopen-2020-039358 doi:10.1080/1028415X.2019.1572940

Watch out for: Well tolerated. Sometimes it causes mild tummy upset.

Alpha-lipoic acid

How much: 600 mg a day. Side effects rise above this with no extra benefit. Weight trials used 1,800 mg.

Studied for: Pain

What the trials found:

• Eases the burning, stabbing and numb feelings of diabetic nerve damage at 600 mg a day, and helped carpal tunnel pain doi:10.2337/dc06-1216 doi:10.1002/14651858.CD012967.pub2 doi:10.1089/jmf.2017.0056

Watch out for: Sometimes upsets your stomach. The R form seems gentler than the mixed form. It can lower the iron you absorb.

Turmeric (curcumin extract)

How much: 500 to 1,000 mg a day of a curcumin extract, with food, for 8 to 12 weeks. Culinary turmeric contains only about 3% curcumin. Avoid products with added black pepper extract (piperine).

Studied for: Pain

What the trials found:

• Eased knee osteoarthritis pain a little after 8 to 12 weeks, by about 9 points on a 100 point scale in the best blinded trial, with a stomach upset rate similar to placebo doi:10.7326/M20-0990 doi:10.1042/BSR20210817 doi:10.2147/CIA.S58535

Worth knowing before you start: Turmeric and curcumin supplements have caused rare but serious liver injury, sometimes with high absorption or black pepper products. Stop and see a doctor if your skin or eyes turn yellow, your skin itches, your urine goes dark or your stools go pale.

Watch out for: Mild stomach upset in some people. Take it with food. Avoid it if you have gallstones, as it makes the gallbladder contract.

Collagen peptides

How much: 10 to 15 g, taken with vitamin C (about 50 mg) 30 to 60 minutes before training or rehab exercises.

Studied for: Pain

What the trials found:

• Eased exercise related knee pain a little more than placebo in young active adults doi:10.3390/nu13020523 doi:10.1139/apnm-2016-0390

Watch out for: Occasional bloating or fullness, as with any protein powder. It is made from animal or fish collagen.

Omega-3

How much: 1 to 2 grams of EPA and DHA a day, with a meal. For low mood, choose one that is mostly EPA.

Studied for: Dry eyes

What the trials found:

• Helped dry eyes in people whose symptoms were severe doi:10.1097/OPX.0000000000001826 doi:10.1089/jop.2024.0160

Watch out for: It can leave a fishy taste or give you heartburn. It thins your blood a little, which matters if you already take blood-thinning medicine.

Zinc

How much: 10 to 25 mg a day, with food. Do not go above 40 mg a day from all sources. For colds, only slow-dissolving lozenges have worked.

Studied for: Eyesight

What the trials found:

• Part of the eye vitamin formula that slowed worsening of age-related macular degeneration doi:10.1167/iovs.12-11552

Watch out for: Makes you feel sick on an empty stomach. Too much for too long blocks copper, which can cause anaemia and nerve problems.

Taurine

How much: 1.5 to 3 grams a day. The blood sugar effect needed 3 grams. For exercise, trials used 1 to 6 grams 1 to 2 hours before.

Studied for: Eyesight

What the trials found:

• Eased tired eyes from screen work in one small trial doi:10.3390/nu15081843

Watch out for: Very well tolerated at normal doses.

Lutein and Zeaxanthin

How much: 10 mg lutein plus 2 mg zeaxanthin a day, with a meal that has some fat in it. Below 5 mg does nothing.

Studied for: Eyesight, Dry eyes

What the trials found:

• Builds the protective pigment at the back of your eye, and improved contrast, glare and recovery from bright light in people with healthy eyes. In macular degeneration it slowed worsening when used in place of beta-carotene doi:10.1093/advances/nmab071 doi:10.3390/nu12102966 doi:10.1001/jama.2013.4997
• May help dry eye, though trials are mixed doi:10.31083/IJVNR36626

Watch out for: Very well tolerated. Very high amounts can turn your skin slightly yellow, which is harmless.