Chrysin (5,7-Dihydroxyflavone) is a potent bioflavonoid found in the plant Passiflora coerula, a member of the passion flower family. Chrysin is the most powerful of several flavonoids that have been tested and found to exhibit anti-estrogenic activity by inhibiting the aromatization process. The effect of a reduction in estrogen production is a reduction in the signal being sent to the pituitary to attenuate the secretion of luteinizing hormone. When LH secretion is maintained or increased, testosterone production is maintained or increased as a consequence.

Chrysin can impact lean body mass by enhancing metabolism of testosterone and androstenedione. This product has been shown to have a significant effect in modulating the response to stress. It binds to receptors in the brain known as the benzodiazepine specific receptor sites. As a result, Chrysin can aid athletes in dealing with the stress of training.