We all know that
a key hormone needed to stimulate anabolism and muscle growth.
Although not completely applicable to muscle building, traditional medicine has used tongkat ali (aka eurycoma longifolia or longjack) for centuries as an aphrodisiac and sexual performance enhancer. Tongkat Ali contains high concentrations of steroidal saponins that increase the release of luteinizing hormone and signals the testes to release more testosterone release.
In a study published in the Journal of Ethnopharmacology, scientists tested the effects of oral tongkat ali supplementation on sexual behavior in sexually sluggish and impotent rats. They hypothesized that the supplement would increase serum testosterone levels thereby boosting sexual performance. Furthermore, the researchers looked at the effects of dose (amount of tongkat ali) and duration of supplementation. They found that treatment with 500 mg/kg/day increased sexual performance after 6 days of treatment when compared to placebo controls. These findings were supported by a nearly 2-fold increase in serum testosterone levels in the supplemented animals!
Zanoli P, Zavatti M, Montanari C, Baraldi M. Influence of Eurycoma longifolia on the copulatory activity of sexually sluggish and impotent male rats. J Ethnopharmacol. 2009 Nov 12;126(2):308-13.