Resveratrol

How strong is the research?

1 paper read, 1 supporting.

Who was studied: Mostly people with metabolic syndrome, type 2 diabetes or existing heart disease.

How much to take

daily

150–300 mg

Higher doses may be needed in metabolic syndrome. Effects more pronounced in diabetics.

Before you take it

• No NIH/IOM Tolerable Upper Intake Level (UL) established for resveratrol; gastrointestinal side effects (nausea, diarrhea, abdominal discomfort) have been reported at doses above 1000 mg/day in some trials; doses at and above 500 mg/day should be monitored.
• CYP2C9 and CYP3A4 inhibition demonstrated in vitro; clinical significance at standard supplement doses is uncertain, but potential exists to increase plasma concentrations of warfarin (bleeding risk), statins (myopathy risk), cyclosporine, and other CYP-metabolized drugs.
• Phytoestrogenic (estrogen receptor agonist) activity: use caution or avoid in individuals with hormone-sensitive cancers (breast, ovarian, uterine) or those on concurrent hormone replacement therapy or SERM treatment.
• Platelet aggregation inhibition: additive bleeding risk when combined with anticoagulants (warfarin, heparin), antiplatelet agents (aspirin, clopidogrel), or NSAIDs.
• Oral bioavailability is below 1% due to rapid first-pass sulfation and glucuronidation; achievable plasma and tissue concentrations from standard supplement doses are uncertain, and effects observed in vitro or at high parenteral doses may not translate to oral supplementation at typical label doses.
• Insufficient safety data in pregnancy and lactation; animal studies show phytoestrogenic and potential developmental effects; avoid during pregnancy and breastfeeding.
• Additive hypotensive effect possible when combined with antihypertensive medications (ACE inhibitors, calcium channel blockers, beta blockers); blood pressure should be monitored when initiating or stopping resveratrol supplementation in patients already on antihypertensive therapy.