Vivor is a free, independent guide to what published human trials show about 18 common supplements. It explains the research in plain English, links every claim to the study it came from, and sells nothing.

Which supplements have the best evidence for sleep?

Ashwagandha has the most consistent sleep evidence, improving both how quickly people fall asleep and how long they stay asleep, with a larger effect in people with diagnosed insomnia. Magnesium helps mainly where magnesium levels were low to begin with. Nearly all sleep findings come from people who were sleeping badly, so good sleepers should expect less.

Does creatine only help with strength?

No. Alongside strength and power, trials show creatine protects thinking and reaction time when people are short of sleep, improves memory most clearly in vegetarians, and built bone in a two-year trial in women past the menopause when combined with weight training. Its strength benefit depends on also doing resistance training.

Are supplement effects the same for everyone?

No, and this is why Vivor asks about you before answering. NAD+ precursors add little in young, active people because exercise raises NAD+ naturally. Vinegar flattens the blood sugar spike from a high-sugar meal but did nothing at all with a low-sugar one. Weight-loss trials only recruited people above a healthy BMI.

Which supplements interact with medicines?

Rhodiola and berberine both slow liver enzymes that break down medicines, which can raise drug levels in the blood. Vivor places these in a separate tier that recommends speaking to a doctor first. Green tea changes levels of rosuvastatin and lisinopril, and omega-3 and NAC thin the blood slightly.

Does Vivor sell supplements?

No. Vivor provides information only and does not sell supplements or take money from anyone who does.

Vivor — evidence-based supplement information

Vivor reads published human trials and explains, in plain English, what the research actually shows for 18 common supplements across 30 health outcomes. Every claim links to the trial or meta-analysis behind it. Vivor sells nothing and takes no money from anyone who does.

Everything below describes what researchers measured in trials. It is not a claim that any supplement treats, prevents or cures a disease. Supplements are food, not medicine.

The 18 supplements reviewed

Omega-3, Vitamin D, Magnesium, NAD⁺ (Nicotinamide Riboside), NAC (N-acetylcysteine), Vinegar, Green tea, Creatine, Coenzyme Q10, Zinc, Ashwagandha, Alpha-lipoic acid, Taurine, PQQ, Lutein and Zeaxanthin, Vitamin C, Rhodiola rosea, Berberine.

Sleep

Falling asleep, staying asleep, sleep quality

Sleep is such an important part of our lives. It helps set us up for the day at the beginning. In the evening it helps us relax and allows our brain to undergo important processes. These supplements have shown evidence to help sleep. Use our calculator to see if they are right for you.

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: Sleep

What the trials found:

People slept better during a loading week, alongside better performance doi:10.3390/nu17243831

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 a day, often in the evening. Citrate or glycinate is kinder on your stomach than oxide.

Studied for: Sleep

What the trials found:

Better sleep and fewer night-time leg cramps. It works best if you were low in magnesium to start with PubMed 34719399 PubMed 21199787

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. Some trials used up to 1 to 3 grams. NMN at 250 mg a day is a well-tested alternative.

Studied for: Sleep

What the trials found:

People aged 65 to 75 slept better and walked faster after 12 weeks on NMN 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.

Vitamin D

How much: 1,000 to 2,000 IU a day. A little every day works better than one big dose now and then.

Studied for: Sleep

What the trials found:

Helped people who already had trouble sleeping get better sleep PubMed 28475473

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: 15 to 30 mg a day, with food. Try not to go above 40 mg long term.

Studied for: Sleep

What the trials found:

In trials in women with PMS, sleep and quality of life improved doi:10.1007/s00404-020-05628-w

Watch out for: Makes you feel sick on an empty stomach. Too much for too long blocks copper, and may make weight, blood sugar and blood pressure worse.

Ashwagandha

How much: 300 to 600 mg a day of a standard root extract. Trials used anywhere from 120 mg upwards.

Studied for: Sleep

What the trials found:

In trials, people fell asleep faster and stayed asleep. The effect was bigger in people with insomnia doi:10.1016/j.jep.2020.113276 doi:10.1016/j.sleep.2020.03.012

Watch out for: Usually mild. Health watchdogs have warned about rare cases of liver damage.

Metabolic health

Blood sugar, insulin, weight, cholesterol, fatty liver

Our metabolism is amazing, it helps process everything and gives us the energy we need to function. Our metabolic health is the foundation for a healthy life. These supplements have been shown to improve our metabolism in various ways, from lowering weight and cholesterol to helping regulate blood sugars. Use our calculator to see if they are right for you.

Green tea

How much: About 300 to 400 mg EGCG a day from a standard extract, with food. Brewed tea is the gentler, safer option.

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

What the trials found:

In trials, blood sugar was steadier. It did better than metformin on some measures in women without diabetes PubMed 29415825 PubMed 36501092
Helps your body handle sugar better PubMed 29415825
Weight, waist and BMI all come down a little over 12 weeks PubMed 26093535 PubMed 36558368
Lowers bad cholesterol PubMed 30400924 PubMed 29415825
In trials in fatty liver, liver test results improved PubMed 33206794

Watch out for: Strong extract can upset your liver tests. It also contains caffeine, which can keep you awake.

Omega-3

How much: 1 to 2 grams a day, with a meal. Look for EPA and DHA on the label.

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

What the trials found:

Brings your blood sugar down over time doi:10.1016/j.ejogrb.2020.02.024
Helps your body handle sugar better doi:10.1016/j.clnu.2023.10.007
Trims your waist and helps with weight loss if you carry extra weight doi:10.1039/c3fo60038f
Raises your good cholesterol and lowers your bad cholesterol and blood fats doi:10.1016/j.phrs.2020.105060
Cuts the amount of fat stored in your liver doi:10.1097/MD.0000000000012271

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.

Alpha-lipoic acid

How much: 300 to 600 mg a day. For weight you need 1,200 mg a day or more, for at least 8 weeks.

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

What the trials found:

Better blood sugar. Bigger doses do more doi:10.1016/j.nut.2020.111041 doi:10.1016/j.metabol.2018.07.002
Helps your body handle sugar better doi:10.1016/j.clnesp.2019.03.015
A small drop in weight. You need 1,200 mg a day or more, for 8 weeks or longer doi:10.1016/j.clnu.2017.06.002 doi:10.1111/obr.12528
Better cholesterol, more so with a bigger dose over longer doi:10.1016/j.nut.2018.08.004
In trials in fatty liver, inflammation fell and body make-up improved doi:10.1111/jcpt.12784

Watch out for: Sometimes upsets your stomach. The R form seems gentler than the mixed form.

Berberine

How much: 500 mg to 1.5 g a day, split across 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:

In trials, blood sugar came down. It did about as well as metformin in PCOS doi:10.1530/EJE-11-0616
Helps your body handle sugar and release insulin better doi:10.1530/EJE-11-0616
Lowers weight and BMI. Bigger doses do more doi:10.1530/EJE-11-0616
Lowers bad cholesterol by a different route from statins doi:10.1055/s-0031-1296582
In trials in fatty liver, liver test results improved doi:10.1530/EJE-11-0616

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

Vinegar

How much: About 15 to 30 ml a day (1 to 2 tablespoons). Always mix it into water and drink it with a meal.

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

What the trials found:

A big drop in the blood sugar spike after a meal PubMed 16015276
Lowers the sugar, insulin and blood fats that rise after eating PubMed 26064976
You feel full sooner, and your waist and weight go down. Too much can make you feel sick PubMed 23979220
Lowers blood fats and bad cholesterol PubMed 26064976

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.

Zinc

How much: 15 to 30 mg a day, with food. Try not to go above 40 mg long term.

Studied for: Blood sugar, Sugar handling, Cholesterol, Fatty liver

What the trials found:

In trials, blood sugar came down, including in people heading towards diabetes doi:10.1111/1753-0407.12621 doi:10.1016/j.jdiacomp.2015.07.001
Helps your body handle sugar better doi:10.1111/1753-0407.12621
Lowers cholesterol and blood fats doi:10.1016/j.jdiacomp.2015.07.001
Less fat in the liver when you are also eating fewer calories doi:10.1007/s12011-019-02015-8

Watch out for: Makes you feel sick on an empty stomach. Too much for too long blocks copper, and may make weight, blood sugar and blood pressure worse.

Taurine

How much: 1 to 3 grams a day. For exercise, trials used 1 to 6 grams taken 1 to 2 hours before.

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

What the trials found:

Better blood sugar if you carry extra weight doi:10.3390/nu17010055 doi:10.1038/s41387-024-00289-z
Helps your body make and use insulin better doi:10.3390/nu17010055
A small effect on weight, alongside blood pressure and cholesterol doi:10.1016/j.ejphar.2020.173533
Better cholesterol doi:10.1016/j.ejphar.2020.173533

Watch out for: Very well tolerated at normal doses.

Magnesium

How much: 200 to 400 mg a day, often in the evening. Citrate or glycinate is kinder on your stomach than oxide.

Studied for: Blood sugar, Sugar handling, Cholesterol

What the trials found:

Steadier blood sugar PubMed 25937055
Helps your body handle sugar better PubMed 25937055
Raises your good cholesterol. Not much change to the rest PubMed 36307427

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.

NAC (N-acetylcysteine)

How much: 600 to 1,200 mg, once or twice a day.

Studied for: Blood sugar, Sugar handling, Cholesterol

What the trials found:

In trials in PCOS, blood sugar improved. It did better than metformin in one head-to-head trial PubMed 26654154
In trials in PCOS, sugar handling improved PubMed 26654154
In trials in PCOS, cholesterol improved PubMed 26654154

Watch out for: Can make you feel sick or upset your stomach. It has a mild sulphur smell.

Vitamin D

How much: 1,000 to 2,000 IU a day. A little every day works better than one big dose now and then.

Studied for: Blood sugar, Sugar handling, Fatty liver

What the trials found:

In trials in people with type 2 diabetes, blood sugar came down PubMed 40616487
In trials, people handled sugar better, including women with PCOS PubMed 40616487 PubMed 30400199
Helps your liver, sugar and cholesterol when you are also losing weight PubMed 27631178

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.

Studied for: Blood sugar, Cholesterol

What the trials found:

In trials in type 2 diabetes, blood sugar was steadier doi:10.1002/edm2.70182 doi:10.1016/j.clinthera.2024.12.010
Lowers one type of cholesterol quite a lot, and the rest a little doi:10.1016/j.phrs.2016.01.030

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

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: Weight and appetite

What the trials found:

Builds lean muscle PubMed 38606895

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.

Ashwagandha

How much: 300 to 600 mg a day of a standard root extract. Trials used anywhere from 120 mg upwards.

Studied for: Weight and appetite

What the trials found:

Less weight, lower BMI and fewer food cravings in people under stress doi:10.1177/2156587216641830

Watch out for: Usually mild. Health watchdogs have warned about rare cases of liver damage.

Vitamin C

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

Studied for: Cholesterol

What the trials found:

Lowers bad cholesterol in some groups doi:10.1016/j.nutres.2024.09.014

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

PQQ

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

Studied for: Cholesterol

What the trials found:

A small drop in bad cholesterol, mainly if yours is already high doi:10.3177/jnsv.61.233

Watch out for: No safety worries so far, but fewer than 300 people have been studied across 8 short trials. That is not much to go on yet.

Lutein and Zeaxanthin

How much: 10 mg lutein plus 2 mg zeaxanthin a day, with a meal that has some fat in it.

Studied for: Cholesterol

What the trials found:

A small improvement in cholesterol doi:10.1016/j.prostaglandins.2022.106691

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

Risk reduction

Heart attacks and strokes, blood pressure, cancer, falls

Risk reduction is all about lowering the chances and trying to prevent disease. As we age and go throughout life our risk of illnesses can change, however these supplements have been shown to reduce specific events. Use our calculator to see if they are right for you.

Omega-3

How much: 1 to 2 grams a day, with a meal. Look for EPA and DHA on the label.

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

What the trials found:

Fewer heart problems. The effect is clearest in people who already have heart disease doi:10.1016/j.phrs.2020.105060
Brings your blood pressure down a little doi:10.1016/j.phrs.2020.105060
Helps the lining of your blood vessels work properly doi:10.1016/j.clnu.2020.05.034
In trials, people taking it had fewer heart attacks and strokes, mostly those who already had heart disease doi:10.1016/j.phrs.2020.105060

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.

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

What the trials found:

Fewer heart deaths. The benefit was still there 12 years after just four years of taking it with selenium doi:10.1371/journal.pone.0193120
Brings high blood pressure down doi:10.1002/14651858.CD007435.pub3 doi:10.1093/advances/nmac100
Helps blood vessels work better doi:10.1007/s40292-024-00630-8
In trials, fewer people died of heart problems, and symptoms improved in heart failure doi:10.1371/journal.pone.0193120 doi:10.1186/s12872-017-0628-9

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

Magnesium

How much: 200 to 400 mg a day, often in the evening. Citrate or glycinate is kinder on your stomach than oxide.

Studied for: Heart risk, Blood pressure, Blood vessels

What the trials found:

Lowers your heart disease risk and keeps furring of the arteries steadier PubMed 33030273 PubMed 32618829
Brings blood pressure down PubMed 33030273
Helps blood vessels work better PubMed 32618829

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.

NAC (N-acetylcysteine)

How much: 600 to 1,200 mg, once or twice a day.

Studied for: Heart risk, Blood vessels, Cancer risk

What the trials found:

In trials in type 2 diabetes, the sticky cells in the blood became less sticky PubMed 22935960
Helps blood vessels work better when blood pressure is high PubMed 18268065
Research has linked its antioxidant effect with lower rates of cancer PubMed 11867504

Watch out for: Can make you feel sick or upset your stomach. It has a mild sulphur smell.

Green tea

How much: About 300 to 400 mg EGCG a day from a standard extract, with food. Brewed tea is the gentler, safer option.

Studied for: Heart risk, Blood vessels, Cancer risk

What the trials found:

Research links it with lower rates of heart disease and stroke. It thins the blood a little PubMed 29050464
In trials in type 2 diabetes, arteries were softer and less stiff PubMed 31084381
Research links it with lower rates of some cancers PubMed 28969404

Watch out for: Strong extract can upset your liver tests. It also contains caffeine, which can keep you awake.

Taurine

How much: 1 to 3 grams a day. For exercise, trials used 1 to 6 grams taken 1 to 2 hours before.

Studied for: Heart risk, Blood pressure, Blood vessels

What the trials found:

Better heart risk markers overall doi:10.1186/s12937-024-00995-5
Brings blood pressure down. This is the thing it does most reliably doi:10.1007/s11906-018-0881-z doi:10.1161/HYPERTENSIONAHA.115.06624
Helps blood vessels work better and stops arteries stiffening after exercise doi:10.1161/HYPERTENSIONAHA.115.06624 doi:10.1139/apnm-2015-0560

Watch out for: Very well tolerated at normal doses.

Berberine

How much: 500 mg to 1.5 g a day, split across meals. Your body absorbs it poorly, so the type you buy matters.

Studied for: Blood pressure, Blood vessels, Cancer risk

What the trials found:

Brings blood pressure down doi:10.1055/s-0031-1296582
Helps blood vessels work better doi:10.1055/s-0031-1296582
Fewer bowel growths coming back doi:10.1055/s-0031-1296582

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: Blood vessels, Bone strength

What the trials found:

Better blood vessel function in older adults PubMed 39796490 PubMed 25853877
Stronger bones when you combine it with weight training. One trial in older women ran for two years doi:10.1249/MSS.0000000000002722 doi:10.1080/15502783.2026.2668435

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.

Vitamin D

How much: 1,000 to 2,000 IU a day. A little every day works better than one big dose now and then.

Studied for: Cancer risk, Falls and broken bones

What the trials found:

In trials, fewer people died from cancer, although the number who developed it did not change pmc.ncbi.nlm.nih.gov/articles/PMC6851517/
Older people had fewer falls and fewer broken bones PubMed 32846760

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.

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 doi:10.3945/ajcn.111.027995 doi:10.1097/MD.0000000000019274
Helps blood vessels relax properly when blood pressure or cholesterol is high doi:10.1161/01.cir.97.22.2222 doi:10.1161/01.cir.95.12.2617

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

Zinc

How much: 15 to 30 mg a day, with food. Try not to go above 40 mg long term.

Studied for: Blood pressure

What the trials found:

Brings blood pressure down doi:10.1016/j.jdiacomp.2015.07.001

Watch out for: Makes you feel sick on an empty stomach. Too much for too long blocks copper, and may make weight, blood sugar and blood pressure worse.

Alpha-lipoic acid

How much: 300 to 600 mg a day. For weight you need 1,200 mg a day or more, for at least 8 weeks.

Studied for: Blood vessels

What the trials found:

Helps blood vessels work better doi:10.1161/01.CIR.0000153272.48711.B9 doi:10.1080/10408398.2020.1861425

Watch out for: Sometimes upsets your stomach. The R form seems gentler than the mixed form.

Recovery and inflammation

Post-exercise repair, inflammation markers

After exercise or injury our body will undergo inflammation which can be useful for repair and healing, however too much inflammation can make repair worse. These supplements have been shown to improve recovery post exercise or lower inflammation. Use our calculator to see if they are right for you.

NAC (N-acetylcysteine)

How much: 600 to 1,200 mg, once or twice a day.

Studied for: Recovery after exercise, Inflammation

What the trials found:

Helps you perform on back-to-back days of exercise PubMed 22089305
Lowers inflammation markers in your body PubMed 23341476

Watch out for: Can make you feel sick or upset your stomach. It has a mild sulphur smell.

Omega-3

How much: 1 to 2 grams a day, with a meal. Look for EPA and DHA on the label.

Studied for: Recovery after exercise, Inflammation

What the trials found:

Calms the inflammation your body makes after hard exercise doi:10.3390/nu18030539
Lowers the markers doctors use to measure inflammation in your body doi:10.3390/nu18030539 doi:10.1186/s12967-022-03604-3

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.

Studied for: Recovery after exercise, Inflammation

What the trials found:

Less muscle damage and stress on the body after hard exercise doi:10.1016/j.clnesp.2024.01.015
Lowers inflammation markers in your body doi:10.1016/j.phrs.2017.08.011 doi:10.1016/j.phrs.2019.104290

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

Taurine

How much: 1 to 3 grams a day. For exercise, trials used 1 to 6 grams taken 1 to 2 hours before.

Studied for: Recovery after exercise, Inflammation

What the trials found:

Less muscle damage and inflammation after training doi:10.23736/S0022-4707.17.07497-7
Lowers inflammation markers. Bigger doses do more doi:10.1038/s41430-021-01010-4

Watch out for: Very well tolerated at normal doses.

Alpha-lipoic acid

How much: 300 to 600 mg a day. For weight you need 1,200 mg a day or more, for at least 8 weeks.

Studied for: Recovery after exercise, Inflammation

What the trials found:

Your strength comes back faster after hard training. It works well next to creatine doi:10.1186/s12970-020-00389-y
Lowers inflammation markers in your body doi:10.1016/j.numecd.2018.04.003 doi:10.1007/s00228-020-02844-w

Watch out for: Sometimes upsets your stomach. The R form seems gentler than the mixed form.

Vitamin C

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

Studied for: Recovery after exercise, Inflammation

What the trials found:

Less stress on your body after long endurance events doi:10.1089/10799900050198480
Lowers a key inflammation marker doi:10.1016/j.freeradbiomed.2008.09.030

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

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: Recovery after exercise

What the trials found:

You bounce back faster between sessions PubMed 38606895

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 a day, often in the evening. Citrate or glycinate is kinder on your stomach than oxide.

Studied for: Recovery after exercise

What the trials found:

Less muscle soreness after exercise PubMed 34719399

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. Some trials used up to 1 to 3 grams. NMN at 250 mg a day is a well-tested alternative.

Studied for: Inflammation

What the trials found:

In a trial in people with a long-term lung condition, one inflammation marker fell 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.

Green tea

How much: About 300 to 400 mg EGCG a day from a standard extract, with food. Brewed tea is the gentler, safer option.

Studied for: Recovery after exercise

What the trials found:

Less muscle damage after exercise, and better results from training PubMed 29746891 PubMed 31747468

Watch out for: Strong extract can upset your liver tests. It also contains caffeine, which can keep you awake.

Zinc

How much: 15 to 30 mg a day, with food. Try not to go above 40 mg long term.

Studied for: Inflammation

What the trials found:

Lowers inflammation markers in your body doi:10.1007/s12011-019-01757-9

Watch out for: Makes you feel sick on an empty stomach. Too much for too long blocks copper, and may make weight, blood sugar and blood pressure worse.

Ashwagandha

How much: 300 to 600 mg a day of a standard root extract. Trials used anywhere from 120 mg upwards.

Studied for: Recovery after exercise

What the trials found:

Better recovery after exercise, and steadier stress levels through hard training blocks doi:10.3390/nu10111807 doi:10.3390/nu18020230

Watch out for: Usually mild. Health watchdogs have warned about rare cases of liver damage.

PQQ

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

Studied for: Recovery after exercise

What the trials found:

May help you tune in to what your body is telling you after hard exercise doi:10.1038/s41598-025-34191-0

Watch out for: No safety worries so far, but fewer than 300 people have been studied across 8 short trials. That is not much to go on yet.

Lutein and Zeaxanthin

How much: 10 mg lutein plus 2 mg zeaxanthin a day, with a meal that has some fat in it.

Studied for: Inflammation

What the trials found:

Lowers inflammation markers linked to heart disease doi:10.1016/j.numecd.2024.05.009

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

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: Recovery after exercise

What the trials found:

May reduce muscle damage after exercise doi:10.3390/nu17060940

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

Berberine

How much: 500 mg to 1.5 g a day, split across meals. Your body absorbs it poorly, so the type you buy matters.

Studied for: Inflammation

What the trials found:

Lowers inflammation markers in your body doi:10.1055/s-0031-1296582

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

Exercise and strength

Power, endurance, oxygen delivery

To improve our exercise capacity people often use supplements. Our choices have shown improvements in outcomes with exercise. Use our calculator to see if they are right for you.

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, Endurance

What the trials found:

More strength and power, and faster recovery. The gains are biggest when you also lift weights PubMed 38606895 PubMed 37206869 PubMed 32865944
Faster swimming and better repeated sprints PubMed 16083193 doi:10.1186/s12970-018-0226-y

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 a day, often in the evening. Citrate or glycinate is kinder on your stomach than oxide.

Studied for: Strength and muscle, Endurance

What the trials found:

Better jumping and sprinting, more strength, and less lactic acid build-up PubMed 34719399
Makes exercise feel easier after a bad night's sleep PubMed 9626901

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. Some trials used up to 1 to 3 grams. NMN at 250 mg a day is a well-tested alternative.

Studied for: Strength and muscle, Endurance

What the trials found:

Built up calf muscle in people with poor blood flow in their legs doi:10.1038/s41467-024-49092-5
People with poor blood flow in their legs could walk further 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.

NAC (N-acetylcysteine)

How much: 600 to 1,200 mg, once or twice a day.

Studied for: Endurance, Oxygen in your blood

What the trials found:

You can keep going for longer, including on a bike PubMed 15001462 PubMed 24576857
Raises the hormone that makes red blood cells, and raises your blood count PubMed 19093729 PubMed 20354834

Watch out for: Can make you feel sick or upset your stomach. It has a mild sulphur smell.

Vitamin D

How much: 1,000 to 2,000 IU a day. A little every day works better than one big dose now and then.

Studied for: Strength and muscle, Endurance

What the trials found:

Makes muscles stronger, especially in older people and when you also eat enough protein PubMed 29395372 PubMed 30031389
People with more vitamin D in their blood ran faster PubMed 30048414

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.

Ashwagandha

How much: 300 to 600 mg a day of a standard root extract. Trials used anywhere from 120 mg upwards.

Studied for: Strength and muscle, Endurance

What the trials found:

Bigger, stronger muscles when you lift weights doi:10.1186/s12970-015-0104-9 doi:10.3390/nu10111807
Better fitness and recovery in people who train doi:10.12688/f1000research.130932.2 doi:10.1016/j.jep.2021.113929

Watch out for: Usually mild. Health watchdogs have warned about rare cases of liver damage.

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:

Better strength and power, especially for short hard efforts doi:10.3390/nu17060940
Better fitness, though a review of 13 trials found it helps short hard efforts more than long ones doi:10.3390/nu17060940

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

Green tea

How much: About 300 to 400 mg EGCG a day from a standard extract, with food. Brewed tea is the gentler, safer option.

Studied for: Endurance

What the trials found:

Better fitness and better blood results from exercise PubMed 30898134

Watch out for: Strong extract can upset your liver tests. It also contains caffeine, which can keep you awake.

Omega-3

How much: 1 to 2 grams a day, with a meal. Look for EPA and DHA on the label.

Studied for: Endurance

What the trials found:

Helps you keep going for longer, including faster swim times when you train doi:10.3390/nu17142296

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.

Studied for: Endurance

What the trials found:

Older adults got more out of interval training doi:10.3390/nu17243959

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

Taurine

How much: 1 to 3 grams a day. For exercise, trials used 1 to 6 grams taken 1 to 2 hours before.

Studied for: Endurance

What the trials found:

You can keep going for longer, whether you take it once before exercise or every day doi:10.1007/s40279-018-0896-2 doi:10.1111/sms.70123

Watch out for: Very well tolerated at normal doses.

Vitamin C

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

Studied for: Strength and muscle

What the trials found:

Your legs produce force faster, and it helps build collagen when taken with gelatine before training doi:10.1123/ijsnem.2020-0313 doi:10.3945/ajcn.116.138594

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

Cognition and focus

Memory, planning and getting things done, alertness

When we are fatigued or not feeling our best we can commonly feel unalert or tired. Furthermore with ageing we find we become less cognitively nimble. Therefore we have selected supplements shown to improve both. Use our calculator to see if they are right for you.

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, Tiredness

What the trials found:

Better memory. The effect is clearest in vegetarians and anyone with low stores PubMed 21118604
Protects your thinking and reactions when you have not had enough sleep PubMed 17046034 doi:10.1007/s00213-005-0269-z

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: About 300 to 400 mg EGCG a day from a standard extract, with food. Brewed tea is the gentler, safer option.

Studied for: Memory and focus, Tiredness

What the trials found:

Better focus and planning, and slower memory decline PubMed 33751906
Less tiredness PubMed 30898134

Watch out for: Strong extract can upset your liver tests. It also contains caffeine, which can keep you awake.

Ashwagandha

How much: 300 to 600 mg a day of a standard root extract. Trials used anywhere from 120 mg upwards.

Studied for: Memory and focus, Tiredness

What the trials found:

Better memory, attention and reaction time doi:10.1080/19390211.2017.1284970 doi:10.3390/nu16121813
Less tiredness in people under stress doi:10.1177/02698811231200023

Watch out for: Usually mild. Health watchdogs have warned about rare cases of liver damage.

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 thinking in people over 50 doi:10.1002/ptr.5486
Less tiredness and sharper mental performance doi:10.1002/ptr.5486

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

Magnesium

How much: 200 to 400 mg a day, often in the evening. Citrate or glycinate is kinder on your stomach than oxide.

Studied for: Brain protection

What the trials found:

Protects the barrier that shields your brain, and helps recovery after brain surgery PubMed 40035733

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. Some trials used up to 1 to 3 grams. NMN at 250 mg a day is a well-tested alternative.

Studied for: Memory and focus

What the trials found:

In a year-long trial in people with Alzheimer's disease, scores improved doi:10.1186/s13195-025-01693-y

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

NAC (N-acetylcysteine)

How much: 600 to 1,200 mg, once or twice a day.

Studied for: Tiredness

What the trials found:

Less tiredness PubMed 21740986

Watch out for: Can make you feel sick or upset your stomach. It has a mild sulphur smell.

Omega-3

How much: 1 to 2 grams a day, with a meal. Look for EPA and DHA on the label.

Studied for: Memory and focus

What the trials found:

Helps memory and clear thinking as you get older doi:10.1016/j.neurobiolaging.2011.03.019

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.

Studied for: Tiredness

What the trials found:

Less long-term tiredness doi:10.3390/nu13082658

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

Zinc

How much: 15 to 30 mg a day, with food. Try not to go above 40 mg long term.

Studied for: Memory and focus

What the trials found:

Getting enough zinc supports clear thinking doi:10.1016/j.pnpbp.2003.09.034

Watch out for: Makes you feel sick on an empty stomach. Too much for too long blocks copper, and may make weight, blood sugar and blood pressure worse.

Taurine

How much: 1 to 3 grams a day. For exercise, trials used 1 to 6 grams taken 1 to 2 hours before.

Studied for: Memory and focus

What the trials found:

Better thinking and memory doi:10.1080/09637486.2025.2499044

Watch out for: Very well tolerated at normal doses.

PQQ

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

Studied for: Memory and focus

What the trials found:

Better memory, attention and thinking. It works best in people over 40 doi:10.1080/07315724.2021.1962770 doi:10.1039/d2fo01515c doi:10.1007/978-1-4939-3023-4_40

Watch out for: No safety worries so far, but fewer than 300 people have been studied across 8 short trials. That is not much to go on yet.

Lutein and Zeaxanthin

How much: 10 mg lutein plus 2 mg zeaxanthin a day, with a meal that has some fat in it.

Studied for: Memory and focus

What the trials found:

Better vision-linked thinking, faster brain processing, and better brain health in older adults doi:10.1007/s12325-024-02785-1 doi:10.3390/molecules26195794 doi:10.3390/nu13061746

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

Mood and stress

Low mood, worry, stress

We all find times when stress makes life more difficult or our mood feels low. This can be a normal part of life, however the supplements below have shown to help our mood. Use our calculator to see if they are right for you.

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.