Testosterone Replacement Therapy Guidelines

Administration and Formulation

The American Gastroenterological Association recommends using weekly administration of testosterone injections to provide more stable testosterone levels compared to less frequent dosing 1, 2
Injectable testosterone is available in different formulations, including testosterone cypionate (100mg/mL or 200mg/mL), testosterone enanthate (200mg/mL), and testosterone undecanoate (250mg/mL), which requires less frequent dosing 1, 2

The Endocrine Society recommends measuring testosterone levels midway between injections, targeting mid-normal values (similar to normal levels) 1, 2
Initial monitoring should occur 2-3 months after treatment initiation or after any dose change, and once stable levels are confirmed, monitoring every 6-12 months is typically sufficient 2, 3

The American Heart Association notes that injectable testosterone may cause fluctuating serum testosterone levels with peaks and valleys between injections, which may be associated with increased cardiovascular risk compared to transdermal preparations, though evidence is conflicting 2, 4
Common side effects of injectable testosterone include elevated red blood cell count, which occurs more frequently with injectable formulations than with transdermal preparations 4

Testosterone injections offer the benefit of avoiding daily administration and can be advantageous in patients with reduced personal disease-management skills or resources 2, 3