Subcutaneous injection of testosterone is an effective and preferred alternative to intramuscular injection: demonstration in female-to-male transgender patients.

Document Type


Publication Date



Obstetrics & Gynecology, Endocrinology, Pediatrics, MMCRI

Journal Title

The Journal of clinical endocrinology and metabolism.

MeSH Headings

Adult, Analysis of Variance, Body Mass Index, Cohort Studies, Dose-Response Relationship, Drug, Drug Administration Schedule, Female, Humans, Injections, Intramuscular, Injections, Subcutaneous, Male, Middle Aged, Patient Safety, Postmenopause, Premenopause, Retrospective Studies, Testosterone, Transgender Persons


Context: Testosterone (T) is commonly administered intramuscularly to treat hypogonadal males and female-to-male (FTM) transgender patients. However, these injections can involve significant discomfort and may require arrangements for administration by others.

Objective: We assessed whether T could be administered effectively and safely subcutaneously as an alternative to intramuscular (IM) injections.

Design: Retrospective cohort study.

Setting: Outpatient reproductive endocrinology clinic at an academic medical center.

Patients: Sixty-three FTM transgender patients aged >18 years electing to receive subcutaneous (SC) T therapy for sex transition were included. Fifty-three patients were premenopausal.

Intervention: Patients were administered T cypionate or enanthate weekly at an initial dose of 50 mg. Dose was adjusted if needed to achieve serum total T levels within the normal male range.

Main Outcome Measurements: Serum concentrations of free and total T and total estradiol (E2), masculinization, and surveillance for reactions at injection sites.

Results: Serum T levels within the normal male range were achieved in all 63 patients with doses of 50 to 150 mg (median, 75/80 mg). Therapy was effective across a wide range of body mass index (19.0 to 49.9 kg/m2). Minor and transient local reactions were reported in 9 out of 63 patients. Among 53 premenopausal patients, 51 achieved amenorrhea and 35 achieved serum E2 concentrations/mL. Twenty-two patients were originally receiving IM and switched to SC therapy. All 22 had a mild (n = 2) or marked (n = 20) preference for SC injections; none preferred IM injections.

Conclusions: Our observations indicate that SC T injections are an effective, safe, and well-accepted alternative to IM T injections.



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