Liquid Epimedium Male Performance Energy Formula 100% Action Labs Formulated Dietary Supplement Yin yan huo is an herb used in traditional Chinese medicine and translates as "horny goat weed." There are up to 15 different species of horny goat weed in the Epimedium family. Historically the leaves have been used in China and Korea for male health. Horny Goat Weed, often referred to by its scientific name Epimedium, is a plant used in traditional Chinese medicine for healthy male performance. Action Labs® Formulated Action Labs® Formulated is a designation that identifies special Natural Balance R products that are formulated to address specific concerns and meet our exacting quality standards. The Action Labs ® Formulated product line represents a diversified, high- quality line of products that customers rely on for particular needs.