Testosterone (injectable esters and other compounded forms)
Hormone RestorationSexual Well-Being
In plain English
Testosterone is the main male sex hormone; women make smaller amounts too. It is used as replacement therapy when the body does not make enough, which can cause symptoms such as low energy, low sex drive, and reduced muscle mass. Depending on the preparation it is given as an injection under the skin or into muscle, a cream on the skin, a nasal gel, or a lozenge that dissolves in the mouth. A clinician confirms low levels with blood tests before starting and monitors levels and blood counts during treatment.
The science
Testosterone is an androgen that binds the androgen receptor and, after 5-alpha reduction to dihydrotestosterone and aromatization to estradiol, mediates androgenic, anabolic, sexual, and metabolic effects. Esterification (cypionate, enanthate, propionate, undecanoate) prolongs release from an oil depot; shorter esters (propionate) require more frequent dosing. The Endocrine Society recommends therapy only for men with consistent symptoms plus unequivocally low morning testosterone, targeting mid-normal levels, and the Testosterone Trials (T-Trials) showed moderate benefit for sexual function and mood in symptomatic older men without clear vitality/physical benefit. FDA-approved testosterone products exist (injectable, transdermal, nasal, oral undecanoate), but compounded testosterone injectables/creams/troches are not FDA-approved formulations. Key safety considerations: erythrocytosis (monitor hematocrit), suppression of spermatogenesis and fertility, potential exacerbation of untreated severe OSA or lower-urinary-tract symptoms, and contraindication with breast or prostate cancer. In women, the only evidence-based indication is postmenopausal hypoactive sexual desire disorder at low (approximately one-tenth male) doses, per the 2019 Global Consensus Position Statement; supraphysiologic dosing risks virilization.
References
- Bhasin et al., J Clin Endocrinol Metab 2018 (Endocrine Society guideline)
- Snyder et al., N Engl J Med 2016 (Testosterone Trials)
- Davis et al., J Sex Med 2019 (Global Consensus, testosterone in women)