Dosing

Mainstream media created a storm of controversy over resveratrol dosing following publication of promising animal study results (in 2006) that appeared to explain the so-called French paradox—low levels of heart disease in the France even though, generally speaking, they consume a high-fat diet. In the study, resveratrol demonstrated the ability to compensate for many disease-causing factors typically associated with a high-fat diet.²⁹

The potential implications for human health were unfortunately undermined at the time, when the dosing data was miscalculated while attempting to figure out an appropriate human dosage that would be the equivalent to that given the rats in the study. Experts quoted in the media suggested that the dosage of resveratrol, based on the amount per body weight administered to the study rats would equal 35-100 bottles of wine a day.^29-30

However, when translating dosages between species, the appropriate method would be based on surface area and not weight. This is clearly stated in industry pharmacology and toxicology guidelines on estimating safe dosages in initial human clinical trials to test new substances published by the U.S. Department of Health and Human Services Food and Drug Administration.³¹

For general heart health, experts suggest that 8-16 ounces of red grape juice a day—with the precaution that the juice is high in natural sugars.¹⁵ Traditional use of resveratrol-containing herbs, such as Polygonum cuspidatum in Chinese medicine, suggests that 100 mg/day of resveratrol is within typical dosing experience.¹⁵ In modern randomized, placebo-controlled human clinical trials, adult participants have been given resveratrol in doses up to 270 mg/day.²⁹ Study results indicate that dosage ranges of 30-110 mg/day are effective, while doses over 200 mg/day may not offer any advantage and could be unsafe.²⁹ Interestingly, researchers have discovered that resveratrol appears to stimulate the immune system at low concentrations, but acts as an immune suppressor at higher concentrations (over 2.5 mg/L).²

At least one recent clinical trial has demonstrated that single doses of five grams of resveratrol had no significant negative side effects.²⁵ And in two other recent clinical trials conducted with 40 healthy volunteers and 20 people with colorectal cancer, doses of 0.5-5.0 g/day of resveratrol for 29 days for the healthy volunteers and 0.5-1.0 g/day for 8 days prior to surgical removal of tumors in the cancer patients caused no serious adverse side effects.³² Researchers for the manufacturers of a high potency form of resveratrol, resVida®, suggest that clinical data supports an acceptable daily intake for healthy adults of 450 g/day.³³