Resveratrol is a plant polyphenol found in the skin of red grapes, some berries and the root of Japanese knotweed, which is the usual source in supplements. It became famous through lab and animal research on aging pathways, but human trials so far have measured modest, mixed changes in metabolic and vascular markers, and the body absorbs it well yet clears it so fast that very little free resveratrol reaches the blood.
Key Takeaways
- Trans-resveratrol is the commercially available, most-studied form; the cis form is found in wine but has been studied far less.
- About 70% of an oral dose is absorbed, but rapid sulfate and glucuronide conjugation leaves only trace amounts of unchanged resveratrol in plasma.
- Longer lifespan has been seen in yeast, worms, flies and mice on a high-calorie diet, not in mice on a standard diet, and an older-adult cohort found no link between dietary resveratrol and survival.
- A 2026 umbrella review of meta-analyses found small changes in a few markers, such as waist circumference and blood lipids, with most other outcomes rated lower certainty.
- Trials have used roughly 40 mg to 5 g a day; doses of 2.5 g and above caused stomach and bowel upset in a 29-day study.
- At 1 g a day, resveratrol changed the activity of several drug-metabolizing liver enzymes, including CYP3A4, so check with a pharmacist if you take medication.
Evidence grade: Emerging. Dozens of mostly small, short randomized trials and their meta-analyses report mixed results on metabolic and vascular markers, while the longevity findings come from cell and animal research; LiverTox concludes there is no conclusive evidence of benefit in humans.
What Is Resveratrol?
Resveratrol (3,5,4'-trihydroxystilbene) is a natural plant polyphenol with a stilbene structure. It is found in its highest concentrations in the skin of red grapes and in smaller amounts in mulberries, blueberries and blackberries [1]. It is also present in red wine, chocolate and certain roots [6].
Resveratrol is sold without a prescription as a dietary supplement in many preparations and doses. LiverTox, the NIH database on liver safety, points out that the purity of commercial products is rarely well defined [1]. That is worth knowing before you compare one product's label with another, or with a study.
If you are interested in polyphenols more broadly, our guide to antioxidant-rich foods covers the wider family of plant compounds that resveratrol belongs to.
Trans- vs Cis-Resveratrol and Where It Comes From
Resveratrol exists in two mirror-image shapes, called trans and cis [1]. Trans-resveratrol is the form that occurs naturally in grape skin and leaves, and it is the form that is commercially available, so nearly all research uses it. The cis form also occurs in wine, but because it is not sold commercially, little is known about its activity [13].
Besides grapes, resveratrol is extracted from the root of Japanese knotweed (Polygonum cuspidatum, also called Fallopia japonica), an invasive plant whose compounds include resveratrol and the related compound polydatin [7]. A Polygonum cuspidatum extract supplying 40 mg of resveratrol a day has itself been tested in a small randomized trial [14]. Supplements are often standardized to a stated percentage of trans-resveratrol, so the label percentage tells you how much of the total extract is the studied compound.
| Form or source | What it is | How much research |
|---|---|---|
| Trans-resveratrol | The natural form in grape skin; the commercially available form | Nearly all human trials and pharmacokinetic studies [1][13] |
| Cis-resveratrol | Isomer also present in wine; not sold commercially | Very little; a few lab comparisons [13] |
| Japanese knotweed root extract | Root extract used as a supplement raw material; standardized to a percentage of trans-resveratrol | Used in some trials, for example a 40 mg/day extract study [14] |
| Red grapes, berries | Food sources; highest in red grape skin | Food amounts are far below supplement amounts [1][2] |
| Red wine | Contains small amounts alongside alcohol | Not a sensible source; supplements contain hundreds of times more than wine or food [2] |
A note on wine: resveratrol supplements usually contain hundreds of times the amount found in wine or other foods [2], so drinking more red wine is not a meaningful way to reach study doses, and the alcohol carries its own risks. OPA does not recommend drinking alcohol for resveratrol. Whole grapes and berries are a better everyday source of polyphenols, as our article on nutrition for healthy aging explains.
How Resveratrol Works in the Body
In cell culture and animal models, resveratrol shows antioxidant and anti-inflammatory activity. Beyond acting as a direct antioxidant, it stimulates the expression of the body's own antioxidant enzymes and has been linked to the activity of sirtuin 1 (SIRT1) and AMP-activated protein kinase (AMPK), two regulators of how cells handle glucose and fat [1]. Why these lab effects occur, and whether they apply at the concentrations reached in people, remains unclear [1].
In a 30-day crossover trial in 11 men with obesity, 150 mg a day of resveratrol activated AMPK in muscle and raised SIRT1 and PGC-1α protein levels, alongside changes in muscle mitochondrial respiration [11]. The authors described these as calorie restriction-like effects, but the trial was very small and short.
Why so little reaches the blood
Resveratrol's biggest practical problem is bioavailability. In a study of six volunteers given a labeled 25 mg oral dose, at least 70% was absorbed, yet only trace amounts of unchanged resveratrol (under 5 ng/mL) appeared in plasma. The intestine and liver attach sulfate and glucuronide groups to it very quickly, and gut bacteria convert some of it to another compound [3]. In a repeat-dose study, the levels of these conjugated metabolites exceeded those of resveratrol itself by up to about 20-fold [4].
LiverTox notes that the major form found in plasma is the conjugate rather than free resveratrol, and that the component responsible for any activity is not known [1].
The Sirtuin and Longevity Story, Told Honestly
Resveratrol's reputation comes from aging research in simple organisms. In yeast, worms and fruit flies, long-term resveratrol extended lifespan in a way that resembled calorie restriction [1]. Sirtuins, the enzymes at the center of this work, depend on NAD+ to function, which is why resveratrol is often discussed alongside NAD+.
The mammal results are more limited:
- Mice on a high-calorie diet. In mice fed a high-fat diet, resveratrol extended lifespan, seemingly by counteracting the harmful effects of the diet and improving insulin sensitivity and mitochondrial function [1].
- Mice on a normal diet. The same benefit was not seen in normal mice [1]. In a large three-site study in genetically diverse mice, resveratrol at two dietary doses had no significant effect on survival in males or females [9].
- The SIRT1 mechanism. A 2010 biochemistry study found that resveratrol activated SIRT1 only when the test substrate carried an attached fluorescent tag, and did not directly activate it with native substrates, suggesting earlier assay results were partly an artifact [10]. Whether resveratrol affects sirtuins indirectly in people is still being studied.
- People. In a nine-year Italian cohort of 783 adults aged 65 and older, co-authored by National Institute on Aging researchers, urinary resveratrol metabolites from diet were not associated with survival or with inflammatory markers. The share who died was 34.4%, 31.6%, 33.5% and 37.4% from the lowest to the highest quartile [6].
The honest summary: resveratrol is a useful research tool for studying aging biology, but there is no human evidence that it lengthens life. For a broader look at what the research says about eating patterns and aging, see our article on diet and longevity, and our overview of longevity supplements.
What Human Research Measured
Human trials of resveratrol have mostly measured metabolic and vascular markers such as waist size, blood lipids, blood pressure, glucose handling, endothelial (blood vessel lining) function and inflammatory markers. Many were done in people with specific health conditions, so results may not apply to healthy adults.
A 2026 umbrella review pooled 45 systematic reviews covering 129 associations and 68 outcomes from randomized trials. Of 35 statistically significant associations, only four were rated high-certainty under GRADE [12]. A 2024 systematic review of 10 randomized trials in older adults reported mixed results, including some cardiovascular risk biomarkers that rose at high doses, and no significant adverse events [8].
| Outcome | What trials found | Certainty |
|---|---|---|
| Waist circumference | Pooled mean difference of about -0.8 cm [12] | High (small effect) |
| Total cholesterol | About -0.19 mmol/L in adults with overweight [12] | High (small effect), in one subgroup |
| Blood pressure | Lower readings in pooled trials of adults with type 2 diabetes; not shown in general populations at high certainty [12] | High, in one subgroup only |
| Glucose metabolism, endothelial function, inflammatory markers, working memory | Favorable pooled changes [12] | Moderate |
| Exercise adaptation and muscle function in older adults | Improved when resveratrol was combined with exercise [8] | Low (few small trials) |
| Cardiovascular risk biomarkers at high doses | Some increased in overweight older adults [8] | Low (few small trials) |
| Lifespan or survival | No association with dietary resveratrol in an older-adult cohort; no human trials [6] | Not established |
Two cautions apply to this table. First, a statistically significant change in a marker is not the same as a felt or lasting health benefit. Second, trial products, doses and durations varied widely, and LiverTox's overall judgment is that there is no conclusive evidence that resveratrol has beneficial effects in humans [1].
Doses Used in Studies
LiverTox reports that human trials have used anywhere from 20 mg to 5 g a day, and that a typical over-the-counter suggested dose is 500 mg twice daily [1]. Among the studies cited in this article, the metabolic and enzyme trials used 150 mg to 1 g a day.
| Study | Daily dose | Duration | What it measured |
|---|---|---|---|
| Ghanim 2010, 20 healthy adults [14] | 40 mg resveratrol (Polygonum cuspidatum extract) | 6 weeks | Oxidative and inflammatory markers in blood cells |
| Timmers 2011, 11 men with obesity [11] | 150 mg | 30 days | Energy expenditure, muscle mitochondria, blood markers |
| Chow 2010, 42 healthy adults [5] | 1 g | 4 weeks | Drug-metabolizing enzyme activity |
| Brown 2010, 40 healthy adults [4] | 0.5, 1, 2.5 or 5 g | 29 days | Safety, blood levels, IGF-1 |
| Walle 2004, 6 adults [3] | 25 mg single dose | Single dose | Absorption and metabolism |
Timing and How to Take It
No trial has shown that one time of day works better than another. In one study, resveratrol and its metabolites had a plasma half-life of about 9 hours [3]. Follow the directions on your product's label, start at the lower end of studied doses, and do not stack multiple resveratrol products, because the doses add up.
Stacking notes
Research on combining resveratrol with other supplements is thin. The clearest pairing in the literature is with exercise: in older adults, trials that combined resveratrol with an exercise program reported better exercise adaptation and muscle function [8]. Because resveratrol affects liver enzymes at higher doses [5], be cautious about combining it with other supplements or medications processed by the same enzymes, and ask a pharmacist to review your full list.
Where OPA Resveratrol Fits
OPA Resveratrol 600 mg provides 600 mg of resveratrol from Polygonum cuspidatum (Japanese knotweed) root complex standardized to contain 50% trans-resveratrol, in one veggie capsule per serving, 30 capsules per bottle. The label directs adults to take one capsule once a day, 20 to 30 minutes before a meal, or as directed by a healthcare professional. It is formulated for antioxidant, cellular wellness and healthy aging support.
How that compares with research: at 50% standardization, one capsule supplies about 300 mg of trans-resveratrol. That is above the 150 mg used in the 30-day metabolic trial [11] and below the 1 g dose that changed drug-metabolizing enzymes [5] and the 2.5 g and higher doses that caused digestive upset [4]. It sits within the range LiverTox describes for human trials [1].
Safety and Interactions
Side effects. LiverTox describes resveratrol as having few if any side effects. Those reported include minor stomach upset, nausea, headache and fatigue [1]. In a 29-day study, 2.5 g and 5 g a day caused mild to moderate gastrointestinal symptoms, while 0.5 g and 1 g did not [4].
Liver. At high doses of 1.5 to 3 g a day, average liver enzyme levels (ALT and AST) rose slightly and returned to normal after stopping. There are no published reports of clinically apparent liver injury from resveratrol, and LiverTox rates it an unlikely cause [1].
Medication interactions. Talk to your doctor or pharmacist before taking resveratrol if you take:
- Anticoagulants (blood thinners) or antiplatelet medicines. LiverTox lists possible interactions with anticoagulants [1].
- Estrogens or other hormone medicines, also flagged as a possible interaction [1].
- Any medicine broken down by CYP3A4, CYP2D6 or CYP2C9. In 42 healthy volunteers, 1 g a day for 4 weeks inhibited these enzymes and induced CYP1A2, which the authors warned could alter drug levels or effects [5].
Pregnancy and breastfeeding. We found no human data showing that resveratrol supplements are safe during pregnancy, so avoid them unless your clinician advises otherwise. For breastfeeding, LactMed reports no data on resveratrol in breast milk or on infant safety, notes that supplements contain hundreds of times the amount in foods, and advises against using red wine as a source while nursing [2].
Who should check first. Anyone who takes prescription medication, has a liver condition, has surgery scheduled, or is pregnant or breastfeeding should speak with a healthcare provider before starting resveratrol.
Frequently Asked Questions
Is trans-resveratrol better than plain resveratrol?
Trans-resveratrol is the natural, commercially available form, and nearly all research uses it [13]. A label that states the percentage of trans-resveratrol tells you how much of the extract is that studied form. Cis-resveratrol has been studied very little.
Can I get enough resveratrol from red wine or grapes?
Not at study doses. Supplements usually contain hundreds of times the amount found in wine or other foods [2]. Grapes and berries are still worthwhile as part of a polyphenol-rich diet, but drinking wine for resveratrol is not recommended.
What does research say about resveratrol and lifespan?
There is no human evidence that resveratrol lengthens life. Lifespan gains were seen in yeast, worms, flies and mice on a high-calorie diet, not in mice on a normal diet [1][9]. In older adults, dietary resveratrol levels were not associated with survival over nine years [6].
Does resveratrol help memory?
A 2026 umbrella review rated the pooled evidence for an improvement in working memory as moderate certainty [12], and a review of trials in older adults reported better cognitive function in overweight participants [8]. These were small trials of short duration.
What are the side effects of resveratrol supplements?
Side effects are usually mild: stomach upset, nausea, headache and fatigue [1]. Digestive symptoms became more common at 2.5 g a day and above [4]. The bigger practical concern is interactions with medications [1][5].
Why is resveratrol's bioavailability so low?
Most of an oral dose is absorbed, but the intestine and liver convert it very quickly into sulfate and glucuronide conjugates, leaving only trace amounts of unchanged resveratrol in the blood [3]. Whether the conjugates are active is still being studied [1].
Sources
- LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Resveratrol. National Institute of Diabetes and Digestive and Kidney Diseases, NIH. Updated November 30, 2024.
- Drugs and Lactation Database (LactMed). Resveratrol. National Institute of Child Health and Human Development, NIH. Revised September 20, 2021.
- Walle T, Hsieh F, DeLegge MH, et al. High absorption but very low bioavailability of oral resveratrol in humans. Drug Metabolism and Disposition. 2004.
- Brown VA, Patel KR, Viskaduraki M, et al. Repeat dose study of the cancer chemopreventive agent resveratrol in healthy volunteers: safety, pharmacokinetics, and effect on the insulin-like growth factor axis. Cancer Research. 2010.
- Chow HH, Garland LL, Hsu CH, et al. Resveratrol modulates drug- and carcinogen-metabolizing enzymes in a healthy volunteer study. Cancer Prevention Research. 2010.
- Semba RD, Ferrucci L, Bartali B, et al. Resveratrol levels and all-cause mortality in older community-dwelling adults. JAMA Internal Medicine. 2014.
- Cucu AA, Baci GM, Dezsi S, et al. New approaches on Japanese knotweed (Fallopia japonica) bioactive compounds and their potential of pharmacological and beekeeping activities: challenges and future directions. Plants (Basel). 2021.
- Yadegar S, Mohammadi F, Yadegar A, et al. Effects and safety of resveratrol supplementation in older adults: a comprehensive systematic review. Phytotherapy Research. 2024.
- Miller RA, Harrison DE, Astle CM, et al. Rapamycin, but not resveratrol or simvastatin, extends life span of genetically heterogeneous mice. Journals of Gerontology Series A. 2011.
- Pacholec M, Bleasdale JE, Chrunyk B, et al. SRT1720, SRT2183, SRT1460, and resveratrol are not direct activators of SIRT1. Journal of Biological Chemistry. 2010.
- Timmers S, Konings E, Bilet L, et al. Calorie restriction-like effects of 30 days of resveratrol supplementation on energy metabolism and metabolic profile in obese humans. Cell Metabolism. 2011.
- Sun JN, Yang R, Fang L, et al. Effects of resveratrol supplementation on multiple health outcomes: an umbrella review of systematic reviews and meta-analyses of randomized controlled trials. Nutrition Journal. 2026.
- Orallo F. Comparative studies of the antioxidant effects of cis- and trans-resveratrol. Current Medicinal Chemistry. 2006.
- Ghanim H, Sia CL, Abuaysheh S, et al. An antiinflammatory and reactive oxygen species suppressive effects of an extract of Polygonum cuspidatum containing resveratrol. Journal of Clinical Endocrinology and Metabolism. 2010.
Disclosure: OPA Nutrition sells supplements, including products mentioned in this article. This content is for education only and is not medical advice. Statements about dietary supplements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. Talk to your healthcare provider before using any supplement, especially if you take medication or have a medical condition.
Written and reviewed by Michael Gonzales, Founder, OPA Nutrition · Last reviewed: · How OPA researches and writes
