Researchers at Northwestern University Medical School have shown that the principal ingredient in Protykin® functions as a phytoestrogen (plant-based estrogen). In their studies, this ingredient was found to bind to estrogen receptors in cells and resulted in estrogen-like effects, including increased expression of estrogen-regulated genes and the growth of estrogen-dependent cells.

Source: Gehm BD, McAndrews JM, Chien P-Y, Jameson JL, Resveratrol, A Polyphenolic Compound Found in Grapes and Wine Is an Agonist for the Estrogen Receptor, Proceedings of the National Academy of Sciences USA, 94:14138-14143, 1997.