Does Resveratrol Work? What 11 Human Trials Actually Found

Prime Trans-Resveratrol bottle by BoneScience

Resveratrol is the red-grape compound behind years of headlines. We skipped the headlines and read the human trials on PubMed, not the mouse studies, and wrote down what each one found and what it did not.

In 30 seconds: Trials lasting weeks to months used 75 to 1,500 mg of resveratrol a day, with mixed results. Some small trials saw better blood sugar markers, memory scores or muscle power. Others, including a 1,500 mg trial, found nothing beyond placebo. Pooled data show small changes, such as a waist about 0.8 cm smaller. Most of a dose is absorbed, but well under 1% reaches the blood unchanged. Very high doses often caused diarrhea, and resveratrol can change how the body handles some medicines.

By BoneScience Editorial · Sources checked against PubMed abstracts on November 8, 2026 · Last reviewed November 8, 2026

What resveratrol is

Resveratrol is a polyphenol, a plant compound found in red grapes, berries and red wine. It comes in two shapes, trans and cis.

What the human trials found

These are placebo-controlled trials in people. Most were randomized and double-blind.

Study Who and how long Daily dose What it found What it did not find
Timmers 2011 11 healthy men with obesity, 30 days each (crossover) 150 mg Lower resting metabolic rate, liver fat, blood glucose, triglycerides and systolic blood pressure. Only 11 men. One co-author worked for DSM, the maker of the resveratrol tested.
Poulsen 2013 24 men with obesity, 4 weeks 1,500 mg Nothing beyond placebo. No change in insulin sensitivity (the main outcome), blood pressure, energy use, organ or belly fat, or inflammation markers.
Yoshino 2012 Women after menopause without obesity, 15 per group, 12 weeks 75 mg Blood resveratrol rose. No change in body composition, blood fats, inflammation markers or insulin sensitivity. Partly funded by DSM.
Thaung Zaw 2021 125 women after menopause, aged 45 to 85, 12 months each (24-month crossover) 150 mg trans-resveratrol A combined thinking-test score, fasting insulin and an insulin resistance index beat placebo. A second report found slightly higher bone density at the lower spine (+0.016 g/cm²) and hip (+0.005 g/cm²). All effects were small (Cohen's d 0.10 to 0.31).
Witte 2014 46 healthy older adults with overweight, aged 50 to 75, 26 weeks 200 mg Better word recall after 30 minutes. HbA1c (a long-term blood sugar marker) and body fat fell versus placebo. Small. Only finishers were compared, matched in pairs.
Huhn 2018 60 older adults aged 60 to 79, 26 weeks 200 mg Nothing significant. The main memory test did not differ from placebo.
Kennedy 2010 22 healthy adults, single doses (crossover) 250 or 500 mg trans-resveratrol Brain blood flow rose with dose. Thinking-test performance did not change.
Gliemann 2013 27 inactive men around 65, 8 weeks of hard training 250 mg trans-resveratrol No benefit. The training gain in maximal oxygen uptake was 45% larger on placebo. Training gains in blood pressure, LDL cholesterol and triglycerides were lost on resveratrol.
Alway 2017 30 adults aged 65 to 80, 12 weeks of exercise 500 mg Knee-extensor peak torque rose 8% and power 14%, with no rise on placebo. No extra heart or blood-vessel benefit over exercise alone. Small.

The two exercise trials point in opposite directions.

What the pooled reviews say

  • Blood sugar markers (2014): 11 trials, 388 people. No change in people without diabetes, whatever the dose or trial length. Changes appeared only in trials that enrolled people with diabetes, a group this guide does not cover.
  • Body weight (2019): 28 trials. Weight about 0.5 kg lower and waist about 0.8 cm smaller than control. Fat mass did not change.
  • Umbrella review (2026): 45 meta-analyses covering 129 links to health measures. Four were rated high-certainty: a waist 0.8 cm smaller, total cholesterol 0.19 mmol/L lower in adults with overweight, and two blood pressure findings in trials that enrolled people with diabetes.

Bioavailability: why so little reaches the blood

In six volunteers, at least 70% of a 25 mg dose was absorbed, yet only trace amounts of unchanged resveratrol (under 5 ng/mL) reached the blood. The gut and liver rapidly convert it to sulfate and glucuronide forms. A later review put oral bioavailability well under 1%, even at bigger or repeated doses. After a single 5 g dose, blood resveratrol peaked at 539 ng/mL at about 1.5 hours, and exposure to the converted forms was up to 23 times higher. Whether those forms are active in people is unclear.

  • Food: in 8 healthy adults, a high-fat breakfast cut resveratrol exposure by 45% compared with a standard breakfast.
  • Quercetin: in the same study (2,000 mg of resveratrol twice a day, 8 people), adding 500 mg of quercetin twice a day did not change resveratrol levels. We found no study of the pair at lower doses.
  • Piperine: in 23 adults, 20 mg of piperine (from black pepper) with 250 mg of trans-resveratrol raised brain blood flow more than resveratrol alone, but blood resveratrol did not differ (measured in a separate group of 6).

Trans-resveratrol vs resveratrol

Trans-resveratrol is the form named in the trials that state one, including the 24-month and training trials. Light can flip trans into cis. In one lab test, ultraviolet light converted about 60% of dissolved trans-resveratrol to cis in 330 minutes, and little is known about how cis-resveratrol behaves in the body. That was strong UV on a liquid, not capsules on a shelf. Still, a label listing trans-resveratrol with an amount tells you what you get.

Doses the studies used

Daily amount How long Study
25 mg Single dose Walle 2004
75 mg 12 weeks Yoshino 2012
150 mg 30 days; 12 months Timmers 2011; Thaung Zaw 2021
200 mg 26 weeks Witte 2014; Huhn 2018
250 mg Single dose; 8 weeks Kennedy 2010, Wightman 2014; Gliemann 2013
300 or 1,000 mg 90 days Anton 2014
500 mg 10 days; 12 weeks Bedada 2016; Alway 2017
1,500 mg 4 weeks Poulsen 2013
4,000 mg Absorption study la Porte 2010
0.5 to 5 g Single doses Boocock 2007

Dose alone does not explain the mixed results: the 75 mg and 1,500 mg trials both found nothing.

Side effects and safety

  • Single doses up to 5 g caused no serious adverse events in healthy volunteers.
  • 2,000 mg twice a day: 6 of 8 healthy adults had diarrhea.
  • 1,500 mg a day: one man developed a widespread rash after a week and was withdrawn.
  • 300 or 1,000 mg a day for 90 days: in 32 older adults, blood chemistry stayed normal and adverse events matched placebo, but two people on 1,000 mg withdrew with stomach or bowel problems. The lead author advises the product's supplier. A later analysis of 29 people in this pilot found two blood markers linked to heart risk (sVCAM-1 and tPAI-1) rose more on 1,000 mg than on 300 mg or placebo. These were lab markers, not illness. The authors call for more study of high doses.
  • Medicines: in 12 healthy volunteers, 500 mg a day for 10 days roughly doubled blood exposure to diclofenac, a pain reliever (ratio 2.12).

The longest use studied was 12 months at 150 mg a day, and 1,000 mg a day was followed for 90 days. No study above tested pregnancy, breastfeeding or children. If you take any medicine, ask your healthcare provider first.

What the lab studies suggest

In rodents, resveratrol mimicked calorie restriction, and rodent and cell studies pointed to an enzyme called SIRT1. In people the SIRT1 link is inconsistent: the 30-day trial found more SIRT1 protein in muscle, while the 75 mg trial and the training trial found no change.

How to read a resveratrol label

  1. Find the trans-resveratrol amount. For a plant extract, do the math: 500 mg standardized to 50% is 250 mg of resveratrol. Compare that with the doses above.
  2. Purity spec or finished-product test? A figure such as 98% purity usually describes the raw powder. A finished-product test checks the capsule itself.
  3. Lot-matched certificate. The certificate of analysis should carry your bottle's lot number.
  4. Who ran the test. The manufacturer's own lab or an outside lab. One accredited to ISO/IEC 17025, the international standard for testing labs, adds a second set of eyes.
  5. No proprietary blend. A blend hides how much of each ingredient you get.
  6. Every ingredient, every amount. In a multi-ingredient formula, check each ingredient against your medicines.

Questions readers ask

Does resveratrol work?
The results are mixed. Several well-controlled trials, some in healthy people, found no change in blood sugar markers, insulin sensitivity or memory. Others found small gains, such as better fasting insulin over 12 months in women after menopause. Results did not track dose.
What is the difference between trans-resveratrol and resveratrol?
Trans and cis are the two shapes of resveratrol. Trans is the form named in the trials that state one. Light can turn trans into cis, and little is known about cis in the body.
How much resveratrol per day did studies use?
Longer trials used 75 to 500 mg a day, and one ran 12 months at 150 mg. Studies of 1,000 to 1,500 mg a day lasted 4 weeks to 90 days. No dose has been shown to be the right one.
Is resveratrol well absorbed?
At least 70% of a dose is absorbed, but well under 1% reaches the blood unchanged.
What are the side effects of resveratrol?
Diarrhea was common at 4,000 mg a day. Two people left a 1,000 mg study with stomach or bowel problems, and one man on 1,500 mg got a rash. Single doses up to 5 g caused no serious events.
Should I take resveratrol with food?
In one small study, a high-fat breakfast cut exposure by 45% versus a standard breakfast, so an ordinary meal looks better.
Can I take resveratrol with medication?
Ask your doctor first, especially if you take prescription medicine. In 12 healthy volunteers, resveratrol roughly doubled blood levels of diclofenac, a pain reliever. Some formulas, ours included, also contain berberine, which can interact with medicines too.
Prime Trans-Resveratrol bottle by BoneScience
About BoneScienceBoneScience makes Prime Trans-Resveratrol with 1,000 mg of trans-resveratrol per 2-capsule serving (raw material purity 98%), plus berberine HCl 100 mg, quercetin 100 mg from Japanese pagoda tree, cinnamon bark extract 40 mg and BioPerine® 10 mg. Every amount is printed on the label. It is made in a US cGMP facility (21 CFR Part 111). The manufacturer's test report for lot 103601 lists trans-resveratrol at 98% purity, the amounts of all five ingredients, and four heavy metals within specification. One bottle holds 60 capsules, a 30-day supply.*
See Prime Trans-Resveratrol

The studies above were not conducted on BoneScience products. Prime Trans-Resveratrol combines trans-resveratrol with other ingredients, and the finished product has not been tested in a clinical trial.

Related: Berberine vs. Semaglutide: What the Studies Actually Show · Does NMN Work? What 12 Human Studies Actually Found · Black Ginger: What 10 Human Trials Actually Found

Sources

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  20. Anton SD, et al. Exp Gerontol. 2014;57:181-187. PubMed · doi
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*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for general education and is not medical advice.

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