Testosterone Replacement Therapy in Athletes: Sports Injury Treatment Outcomes and Muscle Recovery After Injury – A Narrative Review

Testosterone is a central regulator of muscle protein synthesis, bone mineral density, erythropoiesis, and physical performance. Its clinical use is well established in hypogonadal men, but in athletes it has been increasingly studied for its potential to enhance rehabilitation and recovery after injury. We conducted a narrative review of experimental, clinical, and observational studies evaluating the effects of testosterone on muscle, tendon, and bone physiology, as well as its therapeutic applications in sports-related injury recovery. Literature on androgen receptor signaling, anabolic pathways, and clinical outcomes of testosterone replacement therapy (TRT) was synthesized to highlight mechanistic insights and translational implications. Testosterone exerts anabolic effects through activation of the androgen receptor, stimulation of the AKT–mTOR pathway, and promotion of satellite cell proliferation. These mechanisms enhance muscle hypertrophy, tendon remodeling, and bone integrity. Experimental studies indicate accelerated healing, modulation of inflammatory responses, and protection against oxidative stress. Clinical trials in hypogonadal and older men demonstrate improved lean mass, strength, bone mineral density, and functional outcomes. In athletes, exogenous testosterone enhances maximal strength, muscle cross-sectional area, and explosive performance in a dose-dependent manner. TRT offers therapeutic potential to support recovery and improve musculoskeletal performance, but its application in athletes raises ethical and regulatory concerns. While mechanistic and clinical evidence suggest benefits, high-quality trials in athletic populations are needed to clarify efficacy, safety, and appropriate use in sports medicine.