In the course of the popularity of testosterone supplements in the U.S. market, the statistics of American males that received such testosterone medications have tripled and the replacement treatment has reached a point where it's almost $2 billion worth industry.
Compared to other drugs used for other sicknesses, testosterone is prone to misuse and overuse because of the varying unclear symptoms and indications. Young men are using them to build muscles and improve athletic performance while older males are using them to combat aging and sexual dysfunction.
A new research led by Dr. Joel Finkelstein of Sunnybrook Research Institute attempts to distinguish the effects of estrogen and testosterone on male sexual performance, lean and fat mass, muscular size, and also to determine just the required levels of testosterones for health.
The research implies that the decreased levels of testosterone may mean a decline in strength, lean mass and muscular size. If there is no testosterone conversion to estrogen, this may mean body fat increase. And lack of both will trigger decreased sexual libido.
The team recruited 400 volunteers with ages between 20 and 50. They were transfused with a medication to control the production of both estrogen and testosterone. Within a 16-week period they were given different levels of anastrozole, placebo gel, and testosterone gel to curb the conversion of testosterone to a specific type of estrogen, estradiol.
The findings show that low testosterone levels triggers a decline in libido. But testosterone needs to fall significantly before sexual dysfunction affecting erection capability becomes noticeable.
Moreover, very low testosterone levels also result to decreased lean body mass strength in the legs and size of thigh muscles. Estrogen on its own doesn’t impact muscular size, leg strength or lean body mass. On the other hand, when production of estrogen is blocked, a rise in body fat results whatever the levels of testosterone is. Otherwise, a mild decrease of testosterone levels would cause body fat to increase.
The study was published in the Sept. 11 issue of the New England Journal of Medicine.
