Testosterone is a hormone produced by the male and female reproductive organs that is essential for the development of sexual characteristics, including muscle mass and bone density. It also plays a critical role in the formation of male reproductive organs such as the testes and prostate gland.

Huo, S., Scialli, A. R., McGarvey, S., Hill, E., Tügertimur, B., Hogenmiller, A., Hirsch, A. I., & Fugh-Berman, A. (2016). Treatment of Men for “Low Testosterone”: A Systematic Review. PLoS One, 11 (9). http://dx.doi.org/10.1371/journal.pone.0162480