Epimedium, commonly known as "Horny Goat Weed," has a long history of use in traditional Chinese medicine (TCM) for supporting male vitality and sexual function, which includes claims of boosting testosterone levels. Ancient texts and TCM practitioners have recommended Epimedium for symptoms associated with "kidney yang deficiency," which is loosely interpreted as reduced sexual drive or male reproductive vigor. The herb’s key active component, icariin, has been studied in animal models, where it has sometimes shown modest effects on testosterone production and sexual behavior. However, robust clinical evidence in humans is very limited and inconsistent. Most human studies are small, lack proper controls, or are of poor methodological quality.

Current scientific literature does not provide strong, large-scale clinical trials confirming that Epimedium significantly raises testosterone levels in humans. The evidence is therefore primarily traditional, although early laboratory and animal studies suggest a possible mechanism of action via modulation of nitric oxide and androgen pathways. As a result, the use of Epimedium for testosterone support is justified mainly by its traditional use rather than by robust scientific validation.