Tongat ali’s effects on male sexual enhancement are primarily attributed to eurycomanone, which has steroidogenic activity. Eurycomanone has been shown to have anti-estrogenic effects. It inhibits the aromatase enzyme and prevents the conversion of testosterone to estrogen in the Leydig cells of the testes, the primary site of sperm production in men.
At higher doses, eurycomanone may inhibit phosphodiesterase (PDE) activity, resulting in an accumulation of cyclic AMP, an increase in cholesterol transport, and an increased production of pregnenolone, a precursor for testosterone biosynthesis.[1] Furthermore, activation of the CYP17a enzyme by eurycomanone increased production of testosterone precursors DHEA and androstenedione.[2] Tongkat ali may enhance sperm production by increasing the production of the gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which elevate testosterone and sperm production in the testes, respectively.[3]