Testosterone Replacement Therapy (TRT)
Medical treatment to restore testosterone levels in men with clinically diagnosed hypogonadism
Quick Answer
TRT is medical treatment for men with clinically diagnosed hypogonadism (low testosterone with symptoms). The 2023 TRAVERSE trial (5,246 men) found TRT was cardiovascularly safe, noninferior to placebo for major cardiac events. Benefits include improved sexual function, increased muscle mass, and better bone density. Risks include polycythemia (elevated hematocrit), fertility suppression, and potential prostate effects. TRT requires proper diagnosis, medical supervision, and ongoing monitoring. It is not appropriate for men with normal testosterone seeking enhancement.
High Evidence
Strong clinical trial data in humans
Safety: TRT requires medical supervision with regular monitoring. The 2023 TRAVERSE trial demonstrated cardiovascular safety in men with hypogonadism, but risks include polycythemia, fertility suppression, and other effects.
What Is This?
Testosterone Replacement Therapy (TRT) is medical treatment that provides exogenous testosterone to men whose bodies do not produce adequate amounts. It is indicated for clinically diagnosed hypogonadism.
Forms of TRT:
- Injections: Testosterone cypionate or enanthate (weekly or biweekly)
- Gels/Creams: Daily topical application
- Pellets: Implanted subcutaneously every 3-6 months
- Patches: Daily transdermal application (less common now)
- Men with confirmed low testosterone (<300 ng/dL on two morning tests)
- With symptoms: low libido, erectile dysfunction, fatigue, depression, reduced muscle mass
- After excluding reversible causes (sleep apnea, obesity, medications, other conditions)
- Men with normal testosterone seeking performance enhancement
- Those planning near-term fertility (TRT suppresses sperm production)
- Men with untreated prostate cancer, breast cancer, or severe untreated sleep apnea
- Those unwilling to commit to ongoing treatment and monitoring
How It Works
Direct Hormone Restoration: TRT restores testosterone to physiological levels, reversing symptoms caused by deficiency. Unlike lifestyle interventions that modestly improve production, TRT directly provides the hormone.
Benefits Demonstrated in Research:
- Improved sexual function and libido
- Increased muscle mass and strength
- Improved bone mineral density
- Better mood and energy levels
- Improved metabolic markers (insulin sensitivity, body composition)
- Primary cardiovascular endpoint: 7.0% (testosterone) vs 7.3% (placebo) with HR 0.96
- Conclusion: TRT was noninferior to placebo for major adverse cardiac events
- This addressed longstanding safety concerns about TRT and cardiovascular risk
- TRAVERSE noted higher incidence of atrial fibrillation, acute kidney injury, and pulmonary embolism in testosterone group
- TRT suppresses natural testosterone production, stopping TRT leaves you lower than baseline until recovery (which may be incomplete)
- TRT suppresses spermatogenesis, fertility implications are significant
How to Start
Get properly diagnosed
TRT requires confirmed hypogonadism: two morning testosterone tests below 300 ng/dL (or lab-specific cutoff) with symptoms. Rule out reversible causes like sleep apnea, obesity, or medications.
Tips:
- •Do not start TRT based on one low test, confirm on a second occasion
- •Address reversible causes first (sleep, weight, stress)
- •Get LH/FSH to distinguish primary from secondary hypogonadism
- •Consider alternatives like lifestyle optimization before committing to TRT
Choose administration method
Discuss options with your physician. Injections offer precise dosing and cost-effectiveness but require regular injections. Gels are convenient but risk transfer to others. Pellets are convenient but less adjustable.
Tips:
- •Injections (cypionate/enanthate) are most common and adjustable
- •Weekly or biweekly injections maintain more stable levels than bi-weekly
- •Gels require careful application to avoid transfer to partners/children
- •Consider your lifestyle and preferences when choosing
Establish baseline monitoring
Before starting, get baseline CBC (hematocrit), PSA (if over 40), lipid panel, and liver function. These will be monitored throughout treatment.
Tips:
- •Baseline hematocrit is critical, TRT increases red blood cell production
- •PSA monitoring is recommended for men over 40
- •Discuss fertility preservation if future children are desired
- •Document baseline symptoms to track improvement
Commit to ongoing monitoring
TRT requires lifelong commitment to treatment and monitoring. Hematocrit, testosterone levels, and symptom assessment should occur every 3-6 months initially, then 6-12 months once stable.
Tips:
- •Hematocrit above 54% requires dose reduction or blood donation
- •Target testosterone levels in mid-normal range (typically 500-800 ng/dL)
- •Report new symptoms promptly (especially cardiovascular)
- •Do not stop TRT abruptly, work with your physician if discontinuing
What to Expect
Initial effects
Libido and energy often improve within 3-4 weeks. Some men notice improved mood. Full effects take longer.
Sexual function improves
Erectile function, libido, and overall sexual satisfaction typically improve during this period. Some men notice improved motivation and mental clarity.
Body composition changes
With proper training and nutrition, muscle mass increases and fat mass decreases. Bone density improvements begin. Full body composition changes take 6-12 months.
Maintained benefits
With ongoing treatment, benefits are maintained. Monitoring continues to ensure safety and optimal dosing. This is a lifelong treatment for most men.
Practical Details
Timing
Injection timing depends on ester, cypionate and enanthate are typically injected weekly or biweekly. Gels are applied daily in the morning.
Duration
TRT is typically lifelong treatment. Stopping TRT after prolonged use may result in prolonged hypogonadism as natural production was suppressed. Some men recover natural production; others do not.
Cost
$50-$200/month
Generic testosterone cypionate is inexpensive ($20-50/month). Gels and proprietary formulations cost more ($100-400/month). Monitoring labs add cost. Insurance coverage varies.
Risks & Considerations
Potential Risks
- •Polycythemia (elevated hematocrit) requiring dose adjustment or blood donation
- •Suppression of natural testosterone production and fertility
- •Potential increased risk of atrial fibrillation, acute kidney injury, pulmonary embolism (per TRAVERSE)
- •Acne and skin changes
- •Sleep apnea worsening
- •Testicular atrophy due to suppressed LH
Possible Side Effects
- •Acne
- •Increased hematocrit (requires monitoring)
- •Testicular shrinkage
- •Mood changes (usually improvement, occasionally irritability)
- •Potential gynecomastia if estrogen rises
- •Injection site reactions (if using injections)
Who Should Avoid This
- •Prostate cancer or breast cancer (current)
- •Elevated hematocrit (>54%) before treatment
- •Severe untreated sleep apnea
- •Uncontrolled heart failure
- •Desire for near-term fertility (TRT suppresses sperm production)
- •PSA >4 ng/mL without urological evaluation
Key Research
Cardiovascular Safety of Testosterone-Replacement Therapy (TRAVERSE Trial)
New England Journal of Medicine, 2023
Randomized 5,246 men with hypogonadism and cardiovascular disease/risk to testosterone gel or placebo. Primary cardiovascular endpoint occurred in 7.0% (testosterone) vs 7.3% (placebo), HR 0.96, meeting noninferiority. Higher incidence of atrial fibrillation, acute kidney injury, and pulmonary embolism noted.
View StudyThe Inverse Association between Testosterone Replacement Therapy and Cardiovascular Disease Risk: Meta-Analysis
medRxiv (preprint), 2024
Meta-analysis of 51 studies (~3 million men) found TRT associated with 18% reduction in major adverse cardiovascular events (OR 0.82). Benefits were more pronounced in men with established cardiovascular disease or risk factors.
View StudyTestosterone Replacement Therapy and Cardiovascular Risk: A Review
Missouri Medicine, 2016
Review found TRT in hypogonadal men can improve CVD risk factors, reduce QT interval prolongation, improve heart failure outcomes, and slow atherosclerosis progression. Physiologic testosterone replacement does not pose cardiovascular threat and may be cardioprotective.
View StudyFrequently Asked Questions
Will TRT cause heart problems?
The TRAVERSE trial (2023) found TRT was cardiovascularly safe in men with hypogonadism, noninferior to placebo for major cardiac events. However, it noted higher rates of atrial fibrillation, acute kidney injury, and pulmonary embolism. Overall, evidence does not support increased cardiovascular risk with properly monitored TRT.
Will TRT make me infertile?
TRT suppresses LH and FSH, which suppresses sperm production. Most men on TRT have severely reduced or absent sperm counts. Fertility may recover after stopping TRT, but recovery is not guaranteed. Men planning children should consider alternatives like enclomiphene or hCG.
Can I stop TRT once I start?
You can stop, but natural production may take months to recover and may never fully return to pre-TRT levels, especially after long-term use. Some men require post-cycle therapy (clomiphene, hCG) to help restart production. This is a commitment.
What about prostate cancer risk?
Current evidence does not support that TRT causes prostate cancer in men without existing cancer. However, TRT is contraindicated in men with current prostate cancer. PSA monitoring is recommended for men over 40 on TRT.
Sources
- Endocrine Society: Testosterone Therapy Guidelines(guideline)
- AUA: Testosterone Deficiency Guideline(guideline)
Related Interventions
Disclaimer: This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider before starting any new health practice or supplement. Evidence levels and recommendations can change, this content was last updated December 2025.