Choosing Hormone Replacement Therapy Delivery Methods

Testosterone cypionate is a long-acting ester administered via intramuscular injection into the gluteal or vastus lateralis muscles [11]. The deltoid may be used with smaller injection volumes. Subcutaneous administration into abdominal or thigh adipose tissue is supported by evidence demonstrating comparable serum testosterone concentrations and tolerability [12] and may allow self-administration. Compounded formulations that combine testosterone cypionate with testosterone propionate are used in some practices. Testosterone propionate has a shorter half-life and may provide a more rapid initial rise in serum testosterone [13], followed by the longer-acting cypionate component.

Dosing intervals often range from every one to two weeks, although more frequent administration may reduce hormonal fluctuations. After injection, serum testosterone levels rise to a peak and then decline gradually until the next dose [14]. Initial follow-up laboratory evaluation is often performed midway between the dosing interval [15], meaning dose adjustments can be implemented quickly, allowing flexible titration in response to laboratory findings or symptom changes.

Injectable therapy offers precision, adjustability, and potential for home administration. It may be appropriate for patients whose symptoms fluctuate or prefer to avoid daily application.