Abstract
The incidence of testosterone deficiency and the use of testosterone therapy have increased in recent years, and currently the majority of testosterone prescriptions in the United States and Canada are written by primary care physicians. Meanwhile, the range of available testosterone therapy formulations has widened to include buccal tablets, intramuscular injections, transdermal gels, intranasal gel, subcutaneous injections, oral capsules, and subdermal pellets, each with unique pharmacokinetic and clinical characteristics. Despite the growing use of testosterone therapy and its overall efficacy and safety as demonstrated in clinical trials, concerns exist about the potential impact of testosterone therapy on spermatogenesis and fertility, development of prostate cancer, and risk of polycythemia and cardiovascular events. In addition, ongoing research aims to better characterize the effects of testosterone therapy in specific populations, such as patients aged 65 years and older, patients with obesity and type 2 diabetes, and transgender patients. The range of treatment options and the diversity of patients' goals, preferences, comorbidities, and risk factors necessitate an individualized approach to testosterone therapy that considers each patient's clinical needs alongside the distinct features of different testosterone formulations.