For men with confirmed symptomatic hypogonadism, testosterone replacement therapy is the treatment that restores energy, sexual function, mood, and lean mass in the majority of patients within months. It is also a treatment that has been marketed too aggressively, prescribed too casually, and clouded by a long-running controversy over cardiovascular safety. The 2023 publication of the TRAVERSE trial in the New England Journal of Medicine substantially changed the conversation. Understanding which formulations exist, what the monitoring looks like, and what TRT actually does — and does not do — matters before starting therapy that, for most men, becomes lifelong.
How TRT Works and Who It Is For
TRT supplies exogenous testosterone to maintain serum levels in the mid-normal range (typical target 450 to 600 ng/dL). The Endocrine Society 2018 Clinical Practice Guideline recommends TRT only in men with symptoms of hypogonadism plus two morning total testosterone measurements below the lower limit of normal (approximately 264 ng/dL). The AUA 2018 Testosterone Deficiency Guideline uses a similar framework with a 300 ng/dL threshold.
For men with reversible causes — obesity, sleep apnea, opioid-induced suppression — addressing the underlying cause is the first step. TRT is reserved for those whose deficiency persists or whose symptoms are severe enough to warrant immediate treatment. Importantly, TRT suppresses spermatogenesis and is generally avoided in men actively trying to conceive; alternatives like clomiphene and hCG preserve fertility.
TRT Formulations and Dosing
Multiple delivery routes are FDA-approved, each with trade-offs.
Injections
Testosterone cypionate and enanthate are administered intramuscularly or subcutaneously, typically 100 to 200 mg every 1 to 2 weeks. They are the cheapest option (generic IM testosterone runs $30 to $80 per month) and produce reliable serum levels but with peak-and-trough fluctuations that some men perceive as mood or energy swings. Weekly or twice-weekly subcutaneous administration smooths the curve. Testosterone undecanoate (Aveed) is a long-acting injectable given every 10 weeks but requires in-office administration with a 30-minute observation period due to a rare risk of pulmonary oil microembolism.
Topical Gels and Solutions
AndroGel, Testim, Fortesta, and Axiron are applied daily to the shoulders, upper arms, or axillae. They produce stable serum levels and are convenient, but transfer to women and children through skin contact is a real risk requiring careful application protocols. Brand-name gels run $300 to $500 per month; generic versions are $100 to $200. Insurance coverage often requires step therapy through cheaper alternatives.
Pellets
Testopel implants are placed subcutaneously in office every 3 to 6 months. They produce steady serum levels and avoid daily administration. Costs typically run $700 to $1,200 per insertion, often partially covered by insurance.
Oral and Nasal
Testosterone undecanoate (Jatenzo, Tlando, Kyzatrex) is an FDA-approved oral capsule taken with food twice daily. It avoids first-pass liver toxicity associated with older oral preparations like methyltestosterone. Cost is high — typically $400 to $700 per month — and insurance coverage is variable. Natesto is a nasal gel applied three times daily; the short half-life leads to a more physiologic diurnal pattern but the dosing schedule is inconvenient.
Effectiveness
What patients can realistically expect from TRT — based on the multicenter Testosterone Trials and the TRAVERSE trial — is:
Sexual function: Improvement in libido and erectile function within 4 to 12 weeks, particularly in men whose ED was driven by hormonal deficiency. Men with vascular ED and normal testosterone are unlikely to benefit. See our erectile dysfunction guide for the full picture on ED treatment.
Body composition: Modest increases in lean mass (1 to 3 kg) and decreases in fat mass over 6 to 12 months. Bone mineral density improves measurably. Muscle strength gains are modest unless paired with resistance training.
Mood and energy: Improvement in mood, energy, and well-being is consistently reported but variable. Severe depression generally requires its own treatment.
Cognition: Effects on cognition are inconsistent in published trials. TRT should not be prescribed primarily for cognitive complaints in men without biochemical hypogonadism.
Side Effects and Monitoring
The main side effects worth knowing about — covered in detail in our TRT side effects guide — include erythrocytosis (elevated hematocrit), suppression of spermatogenesis and infertility, acne and oily skin, gynecomastia from peripheral aromatization, sleep apnea exacerbation, prostate-related concerns (PSA elevation, urinary symptoms), and edema. Hematocrit greater than 54% requires dose reduction or therapeutic phlebotomy.
Monitoring per the Endocrine Society guideline involves checking testosterone level, hematocrit, PSA, and lipid panel at 3 months, 6 months, and annually thereafter. DEXA scans every 1 to 2 years are reasonable in men with low baseline bone density.
Cardiovascular Safety
For over a decade, conflicting observational data created uncertainty about whether TRT raised cardiovascular risk. The TRAVERSE trial — a randomized, placebo-controlled trial of 5,200 men with hypogonadism and high cardiovascular risk, published in 2023 — provided the clearest answer to date: TRT was non-inferior to placebo for major adverse cardiovascular events. The trial did identify modestly increased risks of atrial fibrillation, pulmonary embolism, and acute kidney injury, and the FDA updated labels accordingly. The cardiovascular event scare that dominated TRT discussions in the 2010s has been substantially defused, but TRT is not risk-free.
When to seek emergency care: Call 911 or go to the nearest emergency room if you experience chest pain, severe shortness of breath, sudden one-sided weakness or numbness, or a swollen, painful leg while on TRT — these may signal myocardial infarction, pulmonary embolism, stroke, or deep vein thrombosis.
Cost and Insurance
TRT costs vary by formulation. Generic injectable testosterone is $30 to $80 per month at most US pharmacies. Generic gels run $100 to $200; brand-name gels $300 to $500. Pellets cost $700 to $1,200 per insertion every 3 to 6 months. Most commercial insurance plans cover injectable and generic gel formulations with documentation of biochemical hypogonadism; brand-name gels and oral testosterone often require prior authorization. Medicare Part D coverage varies. Self-pay TRT clinics often charge $100 to $300 per month bundled with monitoring, frequently using injectable testosterone. For broader cost considerations, see our healthcare costs guide.
Who TRT Is Right For
The ideal TRT candidate has biochemically confirmed hypogonadism on two morning tests, has clinical symptoms (sexual dysfunction, fatigue, mood changes), is not actively trying to conceive, has had reversible causes addressed, and has discussed cardiovascular and prostate considerations with their clinician. Men with active prostate or breast cancer, untreated severe sleep apnea, severe lower urinary tract symptoms, or hematocrit over 50% are generally not candidates without further evaluation. For coexisting concerns, see andropause, hypogonadism, and the medical conditions hub.
Frequently Asked Questions
How long until TRT starts working?
Sexual symptoms typically improve within 3 to 6 weeks. Energy and mood improvements often appear by 3 months. Body composition changes take 6 to 12 months. Bone density changes over 1 to 2 years. Men who do not feel better after 3 to 6 months of well-dosed therapy may have non-hormonal contributors to their symptoms.
Is TRT a lifelong commitment?
For men with primary hypogonadism (testicular failure), yes — stopping TRT means returning to the deficient state. Men with functional hypogonadism whose underlying cause has been corrected (significant weight loss, sleep apnea treated) may be able to wean off therapy. Discontinuation should be gradual and monitored.
Will TRT make me infertile?
Yes, in most cases. Exogenous testosterone suppresses pituitary LH and FSH, halting spermatogenesis in roughly 90% of men within 3 to 6 months. Sperm production usually recovers after stopping TRT but recovery can take 6 to 24 months and is not guaranteed. Men who want to preserve fertility should use clomiphene or hCG instead, or bank sperm before starting TRT.
Can I get TRT through a telehealth clinic?
Yes. Many US-licensed telehealth platforms now offer TRT through licensed clinicians and partnered pharmacies. Quality varies considerably — reputable platforms follow Endocrine Society or AUA guidelines, require two morning testosterone measurements, and provide ongoing monitoring. Avoid platforms that prescribe testosterone without lab confirmation or that downplay risks.
The Bottom Line
Testosterone replacement therapy is a valuable, well-studied treatment for men with confirmed symptomatic hypogonadism. It is not a wellness optimization tool for men with normal levels and not a substitute for healthy lifestyle for men with reversible causes. With proper patient selection, formulation choice, and monitoring, TRT delivers meaningful improvements in sexual function, body composition, mood, and bone health while keeping risks manageable. A clinician familiar with current guidelines is the practical next step.