Evidence explainerResveratrol

Is Resveratrol Safe? Mild Side Effects in Trials, Open Questions on Interactions

Trials of resveratrol report few problems, but they are short, and reviewers say long-term effects, the right amount and drug interactions remain unstudied.

By Kymata Health editorial teamPublished October 9, 2026Last reviewed October 9, 2026

Medical review pending. Written by our editorial team from the studies cited below; a credentialed clinician has not reviewed it yet. Educational only, not medical advice.

Key takeaways

  • In a review of 10 trials in older adults, no study reported significant adverse events [1].
  • High amounts raised some blood markers of cardiovascular risk in older adults with overweight, the same review found [1].
  • In a dose-escalation study up to 150 mg six times a day, adverse events were mild and similar across groups [2].
  • In 3 short trials of 10 to 1,000 mg/day in adults with type 2 diabetes, no adverse events were observed [3].
  • A 2020 review says data on interactions with other therapies are still lacking [4].

Safety at a glance

From our Resveratrol monograph. Published interactions and cautions only, each with its source.

Who should be careful

  • People taking prescription medicines. Data on interactions between resveratrol and other therapies are still lacking, according to a 2020 review.[10]
  • High amounts. In older adults with overweight, high amounts raised some blood markers of cardiovascular risk, according to a 2024 systematic review.[9]
  • Before you start. Talk to your pharmacist or clinician before adding this supplement, especially if you take prescription medicines, are pregnant or breastfeeding, or have a chronic health condition.[9]

Full Resveratrol safety section

The evidence, graded

Pulled from our monograph evidence tables. Grades follow our evidence-grading policy.

  • Grade CNo effectHbA1c and fasting glucose (Cochrane review)Resveratrol · Meta-analysis · n=50 · 2020 · PMID 31978258Neutral effects on HbA1c, fasting glucose and insulin resistance (very low-certainty evidence). No adverse events were observed in the three trials.
  • Grade CMixedBlood pressureResveratrol · Meta-analysis · n=247 · 2015 · PMID 24731650No significant overall effect on systolic or diastolic pressure. In the higher-dose subgroup (150 mg/day or more), systolic pressure fell by 11.9 mmHg; meta-regression showed no dose effect.

What trials report

A 2024 systematic review of 10 randomized trials in older adults found no study reporting significant adverse events after resveratrol [1]. It also noted that in people with overweight, high amounts increased some biomarkers of cardiovascular disease risk [1].

In a 2009 study, healthy volunteers took trans-resveratrol at 25, 50, 100 or 150 mg six times a day for 13 doses; adverse events were mild and similar between all groups [2].

A 2020 Cochrane review of 3 trials (50 adults with type 2 diabetes) using 10, 150 or 1,000 mg/day for 4 to 5 weeks reported no adverse events, rated as very low-quality evidence [3].

What is still unknown

A 2020 literature review found relatively few reports investigating toxicity and called for long-term human studies [4]. It also found data on interactions with other therapies still lacking [4].

The 2024 review reached the same conclusion: the right amount, long-term effects and interactions with medications still need well-designed trials [1]. Anyone taking prescription medicines should check with a pharmacist before adding resveratrol.

Blood levels stay low

Even with repeated high doses, plasma levels of trans-resveratrol were relatively low, with variation above 40% between people, and higher after morning doses [2]. For what the trials found on benefits, read resveratrol benefits.

Quick answers

Is resveratrol a blood thinner?

Our sources do not establish that; the 2020 review says data on interactions with other therapies are lacking [4]. People on anticoagulants should ask a pharmacist before adding it.

Is resveratrol bad for the kidneys or liver?

Our sources do not report kidney or liver findings in people; the 2020 review calls for long-term human studies of adverse effects [4].

How long were the safety trials?

The diabetes trials lasted 4 to 5 weeks [3]. The older-adult trials varied, and long-term effects remain unstudied [1].

Keep reading

Full monographs

Related articles

Browse the full Supplement & Nutrient Encyclopedia or all supplement articles.

References

  1. [1]Effects and safety of resveratrol supplementation in older adults: A comprehensive systematic review. Phytother Res, 2024. PMID 38433010
  2. [2]Pharmacokinetic and safety profile of trans-resveratrol in a rising multiple-dose study in healthy volunteers. Mol Nutr Food Res, 2009. PMID 19194969
  3. [3]Resveratrol for adults with type 2 diabetes mellitus. Cochrane Database Syst Rev, 2020. PMID 31978258
  4. [4]Potential Adverse Effects of Resveratrol: A Literature Review. Int J Mol Sci, 2020. PMID 32197410

Resveratrol and other dietary supplements are not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the FDA. Talk to your clinician or pharmacist before starting a supplement, especially if you take prescription medicines. This page has no product or affiliate links.

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