This paper reviews our current understanding of the absorption, bioavailability, and metabolism of resveratrol, with a focus on human studies. About 75% of orally consumed resveratrol is absorbed in humans, likely through transepithelial diffusion. However, due to extensive metabolism in the intestine and liver, its oral bioavailability is significantly lower—less than 1%. Increasing the dose or taking resveratrol repeatedly does not seem to improve this.
Metabolic studies on blood and urine samples show that the main metabolites are resveratrol glucuronides and sulfates. Additionally, reduced forms like dihydroresveratrol conjugates and other highly polar unknown compounds may account for up to 50% of an oral dose. While the intestine and liver are major metabolic sites, recent evidence suggests that metabolism by gut bacteria in the colon may play a bigger role than previously thought.
Enzymes like β-glucuronidase and sulfatase, along with the possibility of tissue-specific accumulation of resveratrol, may help increase its effectiveness at target sites. Resveratrol derivatives—especially methylated forms with better bioavailability—could be valuable for future research.
doi: 10.1111/j.1749-6632.2010.05842.x