The role of hormones in muscle hypertrophy

Anabolic-androgenic steroids (AAS) and other hormones such as growth hormone (GH) and insulin-like growth factor-1 (IGF-1) have been shown to increase muscle mass in patients suffering from various diseases related to muscle atrophy. Despite known side-effects associated with supraphysiologic doses of such drugs, their anabolic effects have led to their widespread use and abuse by bodybuilders and athletes such as strength athletes seeking to improve performance and muscle mass. On the other hand, resistance training (RT) has also been shown to induce significant endogenous hormonal (testosterone (T), GH, IGF-1) elevations. Therefore, some bodybuilders employ RT protocols designed to elevate hormonal levels in order to maximize anabolic responses. In this article, we reviewed current RT protocol outcomes with and without performance enhancing drug usage. Acute RT-induced hormonal elevations seem not to be directly correlated with muscle growth. On the other hand, supplementation with AAS and other hormones might lead to supraphysiological muscle hypertrophy, especially when different compounds are combined.