Icariin

Icariin is a flavonol, a type of flavonoid. It is the prenyl acetylation of kaempferide 3,7-O-diglucoside. The compound is derived from several species of plants in the Epimedium family, which are commonly known as Horny Goat Weed or Yin Yang Huo. Extracts from these plants are reputed to produce aphrodisiac effects, and are commonly used in Chinese herbal medicine to enhance erectile function, as well as for several other indications.

It is thought that icariin is likely to be the primary active component of Epimedium extracts, as it has been shown to share several mechanisms of action with compounds used in Western medicine to treat impotence and improve sexual function. In particular, icariin has been demonstrated to act as a PDE5 inhibitor  and to enhance the production of bioactive nitric oxide, as well as mimicking the effects of testosterone. It also shows antioxidant, antidepressant   and neuroprotective  effects in animal studies, as well as stimulating osteoblast activity in bone tissue which has been linked to a possible therapeutic role in the treatment of osteoporosis.