The exact way that horny goat weed works remains unclear. Animal studies have shown that it may influence levels of neurotransmitters such as norepinephrine, serotonin, and dopamine and reduce cortisol levels.
It is interesting to note that although at least 15 fifteen active compounds have been identified in epimedium extracts, (luteolin, icariin, quercetin, and various epimedins), many supplement companies currently use alcohol extracts standardized only for high levels of icariin.