Efficacy of injectable versus transdermal testosterone in increasing lean mass in adult men with low testosterone: a systematic review

Abstract

This systematic review compared the efficacy of injectable versus transdermal testosterone in
increasing lean body mass (LBM) in adult men with hypogonadism over 12 weeks. An analysis
of five studies, including clinical trials, revealed that both formulations significantly increase
LBM. However, injectable testosterone (enanthate/cypionate) demonstrated potentially greater
potency and superior absolute gains, attributed to its supraphysiological serum peaks. In
contrast, transdermal testosterone (gel) provided a more predictable, dose-dependent, and stable
increase in LBM, with a favorable tolerability profile despite the risk of skin irritation. The
evidence suggests that injectable testosterone may be more effective for maximizing muscle
anabolism in the short term, while the transdermal route offers superior hormonal stability.
Therefore, the choice of therapy should be individualized, balancing the goal of maximizing
muscular gains against the preference for treatment convenience and stability