What Is TRT? Testosterone Replacement Therapy for Men Explained

Endogenous means made by your own body, and an androgen is a male hormone. So TRT tops up a hormone the body is short of. This page explains what testosterone replacement therapy is, who it is for, the FDA-approved forms, the benefits and risks shown in trials, and what it costs online. We do not give doses. A clinician decides whether TRT fits you.

What is testosterone replacement therapy for men?

Testosterone is the main male sex hormone. It drives sex drive, muscle, bone strength, body hair and the making of red blood cells and sperm. When the testes, or the brain signals that control them, fail to make enough, men can feel the effects. Doctors call this hypogonadism, which means low testosterone from a problem in the system that makes it.

TRT replaces the missing hormone from outside. It does not fix the cause. While you take it, your own production slows down, because the brain senses there is enough. That is why TRT is usually long term, and why stopping takes planning. Our can you stop TRT guide covers what happens when men come off it.

Who TRT is for

The FDA-approved labels limit TRT to men with confirmed low testosterone linked to a medical cause. The testosterone cypionate label lists "Primary hypogonadism (congenital or acquired)" and "Hypogonadotropic hypogonadism (congenital or acquired)" (DailyMed: Depo-Testosterone label). Primary means the testes are the problem. Hypogonadotropic means the brain does not send the signal.

The same label says to confirm low T with blood tests "measured in the morning on at least two separate days". It also says safety and efficacy, meaning how well it works, in men with "age-related hypogonadism" have not been established. So a single test, or symptoms alone, are not enough. Our low testosterone symptoms guide covers the signs and how testing works.

Types of TRT

Testosterone comes in several forms. Each is FDA-approved in at least one brand or generic, and compounded versions are sold too.

Sources: DailyMed: Depo-Testosterone label, DailyMed: AndroGel 1.62% label, DailyMed: Kyzatrex label, read 14 November 2026.

Compounded creams and many injections sold online are mixed by a pharmacy. The FDA says: "Compounded drugs are not FDA-approved." (FDA: compounding questions and answers). Gels carry their own warning, because the hormone can rub off on women and children who touch the skin.

Benefits of TRT

Trials show real but modest benefits, mostly in sex drive and mood.

• Sex drive and sexual function. In the Testosterone Trials of men 65 and older, a year of gel "had a moderate benefit with respect to sexual function and some benefit with respect to mood and depressive symptoms but no benefit with respect to vitality or walking distance" (Snyder et al., NEJM 2016, PubMed).
• Timing. A review of trials found "Effects on sexual interest appear after 3 weeks plateauing at 6 weeks" (Saad et al., Eur J Endocrinol 2011, PubMed).
• Body and bone. The same review says "Changes in fat mass, lean body mass, and muscle strength occur within 12-16 weeks".
• Anemia. In older men with low T, treatment "significantly increased the hemoglobin levels of those with unexplained anemia" (Roy et al., JAMA Intern Med 2017, PubMed). Hemoglobin is the part of the blood that carries oxygen.

Energy is where results disappoint most. Our TRT timeline shows what tends to change, and when.

Risks of TRT

TRT has label warnings, which is why programs order regular blood tests. The main ones are a rise in red blood cells, higher blood pressure, a rise in PSA (a prostate blood test) and lower fertility.

On heart risk, the large TRAVERSE trial found testosterone "was noninferior to placebo with respect to the incidence of major adverse cardiac events" (Lincoff et al., NEJM 2023, PubMed). Noninferior means it was not worse than a placebo, which is a dummy pill or gel with no drug. The same trial saw more atrial fibrillation, kidney injury and lung clots. After it, the FDA moved to remove heart-outcome wording from the boxed warning while adding "a new warning about increased blood pressure for testosterone products which currently do not have such a warning in their labeling" (FDA: class-wide labeling changes).

Fertility matters most for younger men. The Xyosted label says "The impact on fertility may be irreversible." (DailyMed: Xyosted label). Our TRT side effects guide covers every label warning.

Is TRT a steroid?

Yes, in a strict sense. Testosterone is an anabolic steroid and a Schedule III controlled drug, so it needs a valid prescription. Prescribed TRT aims for the normal range with medical checks, which is different from steroid misuse. Our is testosterone a steroid guide explains the difference.

TRT vs enclomiphene

Some programs offer enclomiphene instead. It is a pill that pushes your own body to make more testosterone, rather than adding the hormone. It may protect sperm production better, but it has no FDA approval as a finished drug. Our enclomiphene vs TRT guide compares cost and trade-offs.

How much does TRT cost?

Online programs sell TRT as a monthly plan, often with labs and a visit on top. The cheapest low-testosterone plan we track today, testosterone or enclomiphene, is Strut Health at $79. HealthRX lists testosterone cypionate from $143 a month on a 12-month plan, and Henry Meds lists Kyzatrex capsules at $179 a month. Every program, with its required fees, is on our TRT price page and testosterone hub.