The optimum dosage of resveratrol is still being determined by science. It is likely dependent on several factors such as body weight, the purpose of the resveratrol regimen (e.g. disease prevention, disease treatment, increased endurance, or mental clarity), method of consumption (e.g. orally, buccally) formulation of the resveratrol (e.g. pills, powders, combination with other compounds or emulsions), other supplements, drugs, or foods consumed by the person, and perhaps even sex, ethnicity, and age. For instance, a recent study revealed that to improve the bioavailability of resveratrol, it should not be consumed with high fat meals (e.g. bacon and eggs).
Even though resveratrol is present in low doses in red wine (around 2 mg. per glass), it appears the resveratrol in wine effectively lessens the risk of heart disease, diabetes, stroke, prostate cancer, and Alzheimer’s disease. Perhaps these benefits result from the fact red wine also contains other polyphenols and alcohol, which could work synergistically with the resveratrol (remember that only moderate amounts of alcohol may be beneficial to human health).
For its part, resveratrol supplementation offers the opportunity to consume resveratrol in much higher doses than found in food or wine. But while (as noted in “Resveratrol Side Effects”), large oral doses (2.5 to 5 grams per day) have been to found to be well tolerated in humans in the short term, the longer term effects of large doses are not yet known.
As such, until more is known about high dose resveratrol supplementation, Dr. David Sinclair of Harvard Medical School currently recommends a maximum resveratrol dose of 250 mg. per day (according to Dr. Sinclair, this dosage amounts to 20 to 40 bottles of red wine per day). Dr. Joseph Maroon, a University of Pittsburgh Medical Center neurosurgeon and author of the book, The Longevity Factor: How Resveratrol and Red Wine Activate Genes for a Longer and Healthier Life, said he takes 500 mg. of resveratrol per day. And Dr. Mehmet Oz has suggested resveratrol supplementation of 500 mg. per day.
What's more, bolstering the argument that relatively small doses of resveratrol can be beneficial in humans, a recent study revealed that only 40 mg. of resveratrol per day decreases inflammation and oxidative stress in humans. Another study revealed that a dosage of just 10 mg./day significantly improved LDL cholesterol, endothelial function, and left ventricle function in human heart attack patients. These studies 'fly in the face' of comments from certain health pundits who have claimed that resveratrol's lack of bioavailability prevents it from improving the health of humans in small doses (i.e. those doses achievable in one supplement pill per day). These commentators are likely just plain wrong in their assertions as the above studies show.
As is the case before beginning any supplement regimen, it is wise to consult with one’s doctor.