Epimedium, also known as Horny Goat Weed, is primarily used in traditional Chinese medicine as an aphrodisiac and for male reproductive health, including the support of the testes and related functions. Historical records date its use back centuries, where it has been prescribed to enhance libido, combat impotence, and address symptoms associated with male aging such as fatigue and decreased sexual vitality. The active compound most often cited is icariin, thought to have some influence on testosterone production and sexual function, although direct effects on testicular health in humans are not well established.

While there are some animal studies suggesting that Epimedium extracts may positively influence testosterone levels and sperm production, robust scientific validation in human subjects is lacking. Most clinical evidence is either preliminary, not peer-reviewed, or focused on general sexual function rather than direct support of testicular structure or health. Therefore, while its use is deeply rooted in traditional practices and there is a modest amount of preclinical research, high-quality human studies are insufficient to fully validate its efficacy for supporting the testes.

In summary, Epimedium's use for testicular support is primarily justified by tradition, with limited scientific backing. Its reputation is largely based on historical usage and anecdotal reports rather than conclusive clinical data.