Testosterone replacement therapy, explained clearly

Testosterone replacement therapy (TRT) is prescription treatment for men with hypogonadism, a condition evaluated through both symptoms or signs and consistently low testosterone measurements. It is not established simply by feeling tired, aging, or one laboratory result.

What TRT is—and what it is not

TRT supplies prescribed testosterone through a formulation selected by a licensed clinician. Many testosterone products are FDA-approved; compounded testosterone preparations are not FDA-approved and do not undergo FDA premarket review for safety, effectiveness, or quality. The Endocrine Society recommends diagnosing hypogonadism only in men with compatible symptoms or signs and unequivocally and consistently low serum testosterone, then evaluating the cause. The AUA guideline likewise emphasizes symptoms or signs plus low total testosterone on separate early-morning tests.

What the care process usually includes

A responsible process is more than a prescription: clinical history, examination as appropriate, properly timed laboratory testing, a discussion of expected benefits and uncertainties, and a monitoring plan. The choice of formulation is not a universal ranking. Injections, topical gels or solutions, patches, pellets, nasal products, and oral testosterone products have different labeling, administration requirements, adverse-effect considerations, and practical tradeoffs.

Important safety boundaries

FDA-approved testosterone products have product-specific indications and prescribing information. In June 2026, FDA requested removal of the prior class labeling limitation concerning age-related hypogonadism. This did not eliminate the need for a clinical diagnosis, individualized risk assessment, monitoring, or compliance with the current label for the prescribed product. FDA communications and labeling describe important risks and warnings; the appropriate warning and monitoring depend on the product and person. The Endocrine Society recommends against starting testosterone in several circumstances, including men planning fertility in the near term and selected high-risk conditions. A clinician can explain what applies to an individual.

Practical next step: bring a complete medication list, prior results, relevant medical history, and reproductive plans to a licensed clinician rather than self-interpreting an isolated result.

Sources and limitations

This educational overview summarizes major U.S. professional and federal sources; it is not a diagnosis, treatment plan, or substitute for an individual clinician's assessment. Guidelines inform care but do not replace judgment, and product labeling, state law, insurance coverage, and telemedicine rules can change. Read the linked primary sources for their full scope and updates.

1. Endocrine Society, Testosterone Therapy in Men With Hypogonadism (2018)
2. American Urological Association, Testosterone Deficiency Guideline
3. FDA, testosterone product safety communication and labeling information
4. FDA: FDA Takes Step Forward on Testosterone Therapy for Men. April 16, 2026.
5. FDA: Testosterone Information
6. FDA, Compounding and the FDA: Questions and Answers