Resveratrol has poor bioavailability due to its rapid and extensive metabolism.[1][2]
Human studies suggest resveratrol can be supplemented at dosages up to 5,000 mg (5 grams) daily with few to no side effects outside of some intestinal upset and nausea.[3][4]
Resveratrol doses of 1,000 mg/day or more may interfere with the biological effects of commonly administered drugs by inhibiting cytochrome p450 isoenzymes. For example, resveratrol inhibits enzymes that play a role in the metabolism of statins, calcium channel blockers, immunosuppressants, antifungals, non-steroidal anti-inflammatory drugs (NSAIDS), anticoagulants, beta-blockers, antidepressants, opioid analgesics, and antihistamines, among others.[5] If you take any medication, consult your doctor before supplementing with resveratrol, no matter the dose.