What Is Resveratrol and Which Foods Contain It? The Evidence

Resveratrol is a stilbene, a small defensive compound that grapes, peanuts, some berries and the root of Japanese knotweed make when they are stressed, and that red wine carries from the grape skin. Food supplies milligrams at most: a glass of red wine holds roughly 0.2 to 2 mg, a bowl of red grapes under 1.5 mg, and knotweed root is where supplement resveratrol comes from.¹ Its human trial record is thin: small studies of four to twelve weeks, null in healthy people, modest glucose effects only in people with diabetes, and one good two-year bone trial in postmenopausal women at 150 mg a day.^{3, 4, 5, 6} In Great Britain resveratrol is an authorised novel food in supplements at up to 150 mg a day for adults, and the label must say that people using medicines should only consume it under medical supervision.^{7, 8}

• Where it is: grape skins, red wine, peanuts, cocoa, a few berries, Japanese knotweed root
• What trials found: small studies; null in healthy people; glucose effects in diabetes; one two-year bone trial
• Who asks first: anyone on an anticoagulant or other medicine, and anyone with a hormone-sensitive condition

What is resveratrol?

A polyphenol of the stilbene family: two benzene rings joined by a short bridge, made by plants in response to fungal attack, UV light and injury, which is why it concentrates in grape skins rather than flesh. It is not a flavonoid, though it is often filed with them; our flavonoids guide covers that larger family. In the body it is absorbed well, at least 70% of a 25 mg dose, then conjugated so fast in the gut wall and liver that free resveratrol in the blood barely registers, under 5 nanograms per millilitre.⁹ That gap between absorbed and available is the central fact about resveratrol. Its reputation came from the 1990s "French paradox" and from lifespan work in yeast and worms; neither is a human trial.

Which foods are high in resveratrol?

Amounts are ranges from published analyses and vary widely by variety and season.¹ The fruit highest in resveratrol is the red grape, mostly its skin; mulberries and a few berries come next. No plate of food gets near the 75 mg of the smallest trial: it would take 50 bottles or more of red wine for one trial day, which ends the "red wine in a capsule" idea. For Indian foods, the answer is peanuts, grapes, pistachios and dark chocolate, none in a quantity that matters.

What are the benefits of taking resveratrol tablets?

The 2011 study that launched the "calorie-restriction mimetic" idea gave 11 obese men 150 mg a day for 30 days and found lower sleeping metabolic rate, liver fat, glucose, triglycerides and systolic blood pressure.² It did not reproduce: 75 mg a day for 12 weeks in healthy postmenopausal women changed no measure of body composition, metabolism or insulin sensitivity,³ and 1,500 mg a day for four weeks in 24 obese men changed nothing on a clamp test, blood pressure or lipids.⁴ Pooled, 11 trials in 388 people found lower fasting glucose, insulin and HbA1c in participants with diabetes and no effect in those without.⁵ Blood pressure across 17 trials fell by a non-significant 2.5 mmHg systolic, significant only at 300 mg a day or more or in diabetes.¹⁰ The one result that stands apart is bone: in the two-year RESHAW crossover, 75 mg twice daily raised lumbar spine density by 0.016 g/cm² and femoral neck by 0.005 g/cm² against placebo, with a 7% fall in a bone-breakdown marker.⁶ Resveratrol has no authorised health claim in Great Britain; its antioxidant and skin wordings were rejected. Can you rebuild bone density sets numbers like these beside exercise, protein and the medicines.

Does resveratrol raise oestrogen?

Not in any human measurement. In laboratory work resveratrol binds oestrogen receptors weakly and behaves as a weak agonist or an antagonist depending on tissue and dose.¹¹ No trial has shown raised oestrogen levels in people, and the longest, two years in postmenopausal women, reported bone changes and no hormonal adverse effects.⁶ Anyone with a hormone-sensitive condition, including a history of breast cancer or endometriosis, should ask their specialist before any resveratrol supplement.

Is it okay to take resveratrol every day, and morning or night?

Daily at up to 150 mg is what the GB authorisation covers for adults, and the two-year trial dosed 150 mg daily without a safety signal.^{6, 7} At 2.5 g a day and above, healthy volunteers had mild to moderate gut symptoms;¹² at about 1 g a day it begins to inhibit the liver enzymes that clear several medicines.¹³ There is no morning-versus-night trial. Take it with a meal, as the trials did. Blended capsules often carry resveratrol in tens of milligrams, below every trialled dose (75 to 1,500 mg) and well inside the 150 mg GB cap, so read the milligrams on the label against those figures.⁷ What is NMN and is it safe in the UK covers the ingredient it is most often blended with.

What is the best way to absorb resveratrol?

With food, and with realistic expectations. Absorption is already high; what is low is the fraction that survives unconjugated.⁹ Piperine, liposomal and micronised forms are sold as the fix; the human data behind them are small blood-level studies, and none has been shown to change a clinical result. The trials that found anything used plain trans-resveratrol.^{2, 6} Check the label says trans-resveratrol, the stable active form. "What is more powerful than resveratrol?" has no answer: there is no scale on which molecules that do different things can be ranked.

What does resveratrol do to the face? Retinol and CoQ10

One eight-week trial in women over 40 found lower wrinkle scores only when 75 mg twice daily was combined with a 1.5% cream; oral resveratrol alone changed nothing measured.¹⁴ The GB register rejected resveratrol's skin and antioxidant claims. "Retinol or resveratrol" compares a dietary polyphenol with a vitamin A derivative applied to the skin, with decades of dermatology trials behind it; they are not alternatives. "CoQ10 or resveratrol" compares two unrelated molecules with no head-to-head trial: CoQ10 is a coenzyme your body makes, resveratrol a plant stilbene. Resveratrol with ferulic acid is a serum question, not a supplement one. Can it make you look younger? No trial has measured it.

Who should not take resveratrol, and what should you not mix it with?

The label statement exists for a reason: people using medicines should only consume it under medical supervision.^{7, 8} Anticoagulants first. Resveratrol inhibits platelet aggregation in the laboratory and inhibits enzymes that clear several medicines, so anyone on warfarin, apixaban, rivaroxaban, edoxaban, dabigatran or an antiplatelet should ask the anticoagulant clinic or pharmacist before taking it; the apixaban question that comes up on heart forums has no human study either way, which is the reason to ask.¹³ Pregnancy and breastfeeding: no data at supplement doses, and food amounts are normal food. Under-18s: the authorisation is for adults. Kidneys: no kidney-function trial of note, so there is no evidence to report. Bone: RESHAW is evidence in women without osteoporosis; osteoporosis itself is diagnosed and treated by your GP. For the cluster's ingredient with a far deeper trial record, see the Wellgard berberine guide.

Frequently asked questions

What fruit is highest in resveratrol?

Red grapes, in the skin; a 160 g bowl holds roughly 0.2 to 1.3 mg. Mulberries, blueberries and cranberries carry far less.¹

What are the negative side effects of resveratrol?

At supplement doses up to 150 mg, none emerged in two years of trial use.⁶ Gut symptoms appeared at 2.5 g a day and above,¹² and medicine interactions become plausible from about 1 g.¹³

Why avoid resveratrol?

If you take medicines, especially anticoagulants, until you have asked; if you have a hormone-sensitive condition; if you are pregnant, breastfeeding or under 18.

Is resveratrol a flavonoid?

No. It is a stilbene; flavonoids are a different polyphenol family with a different ring structure.

Sources

1. Burns J, et al. Plant foods and herbal sources of resveratrol. Journal of Agricultural and Food Chemistry, 2002. PubMed 12010007.
2. Timmers S, et al. Calorie restriction-like effects of 30 days of resveratrol supplementation in obese humans. Cell Metabolism, 2011. PubMed 22055504.
3. Yoshino J, et al. Resveratrol supplementation does not improve metabolic function in nonobese women with normal glucose tolerance. Cell Metabolism, 2012. PubMed 23102619.
4. Poulsen MM, et al. High-dose resveratrol supplementation in obese men: a randomized, placebo-controlled trial. Diabetes, 2013. PubMed 23193181.
5. Liu K, et al. Effect of resveratrol on glucose control and insulin sensitivity: meta-analysis. American Journal of Clinical Nutrition, 2014. PubMed 24695890.
6. Wong RH, et al. Regular supplementation with resveratrol improves bone mineral density in postmenopausal women (RESHAW). Journal of Bone and Mineral Research, 2020. PubMed 32564438.
7. Food Standards Agency. Register of authorised novel foods, entry NOVEL-138 (trans-resveratrol): adults, 150 mg a day, label statement on medicines. data.food.gov.uk/regulated-products.
8. EFSA NDA Panel. Safety of synthetic trans-resveratrol as a novel food. EFSA Journal, 2016. doi.org/10.2903/j.efsa.2016.4368.
9. Walle T, et al. High absorption but very low bioavailability of oral resveratrol in humans. Drug Metabolism and Disposition, 2004. PubMed 15333514.
10. Fogacci F, et al. Effect of resveratrol on blood pressure: meta-analysis of randomised controlled trials. Critical Reviews in Food Science and Nutrition, 2019. PubMed 29359958.
11. Gehm BD, et al. Resveratrol, a polyphenolic compound found in grapes and wine, is an agonist for the estrogen receptor. Proceedings of the National Academy of Sciences, 1997. PubMed 9391166.
12. Brown VA, et al. Repeat dose study of resveratrol in healthy volunteers: safety and pharmacokinetics. Cancer Research, 2010. PubMed 20935227.
13. Detampel P, et al. Drug interaction potential of resveratrol. Drug Metabolism Reviews, 2012. PubMed 22788578.
14. Rao A, et al. Trans-resveratrol and visible signs of skin ageing in women over 40: 8-week randomised trial. Frontiers in Aging, 2025. PubMed 41488277.

This article is general information, not medical advice; if you take any prescribed medicine, have a hormone-sensitive condition, or are pregnant or breastfeeding, ask your GP or pharmacist before taking a resveratrol supplement.