Epimedium

Epimedium, also known as barrenwort, bishop’s hat, fairy wings, horny goat weed, or yin yang huo (Chinese: 淫羊藿), is a genus of flowering plants in the family Berberidaceae. The majority of the species are endemic to China, with smaller numbers elsewhere in Asia, and a few in the Mediterranean region.
Epimedium species are deciduous or evergreen hardy perennials. The majority have four-parted “spider-like” flowers in spring.
The species used as a dietary supplement is Epimedium grandiflorum. It contains icariin, which is a weak PDE5 inhibitor in vitro. Its clinical effects are unknown.

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