Ginseng

Ginseng, a root from the Panax Quinquefolium herb, contains tetracyclic triterpenoid saponins (ginsenosides for short), which help enhance physical performance. This "energy boost" is probably not the only thing that contributes to the aphrodisiac qualities of ginseng. The other likely reason is that ginseng is believed to have an effect on the hypothalmic-pituitary-adrenal axis (HPTA) in which the root elevates plasma levels of corticotropin and corticosteroids.

This data seems to go against the use of ginseng in athletic situations, as corticosteroids are known to cause muscle loss. Other possible side effects of ginseng in large doses are high blood pressure, anxiety, vaginal bleeding and diarrhoea.

However, at moderate doses ginseng is a very safe natural aphrodisiac that has been used for centuries in China and Korea, as well as Siberia - BUT there really is no such thing as a "Siberian ginseng". That's just a marketing ploy in which companies use an entirely different speacies of adaptogen, which does not contain the ginsenosides associated with ginseng's aphrodisiac properties.