Few health topics are as clouded by myths and misinformation as testosterone replacement therapy (TRT). Men hear about heart attacks, prostate cancer, and permanent infertility — and choose out of fear to forgo a treatment that could fundamentally improve their quality of life. But what does current research actually say? This article separates fact from fiction — transparently, with nuance, and without trivializing real risks.
Myth 1: TRT Causes Heart Attacks
How the Myth Originated
In 2014, a study made headlines suggesting a link between TRT and increased heart attack risk. The media seized on the findings immediately. What was lost in the coverage: the study had significant methodological flaws. It was subsequently criticized sharply by experts, and the authors were required to publish two corrections.
What Science Says Today
The largest and most important study on this topic is the TRAVERSE trial, published in 2023 in the New England Journal of Medicine [1]:
- 5,246 participants aged 45–80 years
- Mean follow-up of 33 months
- Result: No increased risk of major adverse cardiovascular events (heart attack, stroke, cardiovascular death) with TRT compared to placebo
A large meta-analysis of 35 interventional studies also reached the same conclusion: testosterone therapy in men with documented deficiency does not increase cardiovascular risk [2].
What the TRAVERSE Trial Also Revealed
Beyond cardiovascular safety, the TRAVERSE trial yielded important secondary findings. A sub-analysis by Bhasin et al. (2024) examined TRT's effects on depressive symptoms among the 5,204 randomized participants. The results were noteworthy: 50.8% of participants had clinically significant depressive symptoms at baseline, and TRT produced significantly greater improvements in mood and energy compared to placebo [6]. This underscores that appropriately indicated TRT is not only safe but also effective against common comorbidities of hypogonadism.
Important: These data apply to men with documented testosterone deficiency treated under medical supervision. Self-medicating with testosterone at supraphysiological doses is an entirely different scenario.
The European Perspective: EAU 2025
The updated European Association of Urology (EAU) 2025 guidelines confirm the cardiovascular safety of TRT in appropriately diagnosed late-onset hypogonadism and recommend offering TRT as a safe therapeutic option for eligible patients [8].
Myth 2: TRT Causes Prostate Cancer
The Historical Background
This concern traces back to Charles Huggins, who discovered in 1941 that testosterone deprivation caused prostate tumors to regress. Since then, the erroneous reverse logic prevailed: if less testosterone is beneficial, more testosterone must be harmful.
The Saturation Model
Harvard urologist Abraham Morgentaler fundamentally overturned this thinking with the saturation model [3]: androgen receptors in the prostate are fully occupied at relatively low testosterone levels. Additional testosterone beyond this threshold has no further effect on prostate tissue — much like a sponge that is already fully saturated.
Current Evidence
| Study | Participants | Finding |
|---|---|---|
| TRAVERSE trial (2023) [1] | 5,246 men | No increased prostate cancer risk with TRT |
| Boyle meta-analysis (2016) [4] | 18 studies, >5,000 men | No association between TRT and prostate cancer |
| Pastuszak (2016) [5] | Over 1,000 men | No increased risk, even in men with elevated baseline PSA |
The current EAU position: TRT is not contraindicated in men without active prostate cancer. Even men with successfully treated prostate cancer may receive TRT under careful surveillance.
Our Recommendations
- PSA measurement before starting therapy and regularly thereafter (every 3–6 months in the first year)
- Digital rectal examination as baseline
- If PSA rises rapidly: urological evaluation
Myth 3: TRT Causes Permanent Infertility
What Actually Happens
When exogenous testosterone is administered, the body detects the elevated levels and downregulates its own production — both testosterone synthesis and spermatogenesis. Sperm counts can temporarily fall dramatically, potentially reaching complete azoospermia.
Is the Effect Reversible?
In the vast majority of cases: yes. A comprehensive analysis published in The Lancet examined spermatogenic recovery after testosterone discontinuation [7]:
- 67% of men regained normal sperm counts within 6 months
- 90% within 12 months
- 100% within 24 months
Options for Men Who Want Children
Men with fertility goals need not forgo treatment entirely. Proven alternatives exist:
- HCG (human chorionic gonadotropin): Directly stimulates the testes, maintaining both testosterone production and spermatogenesis
- Clomiphene: An oral SERM that signals the body to produce more testosterone without suppressing sperm production
- TRT + HCG combination: Testosterone therapy paired with HCG to preserve testicular function
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Actual Side Effects — and How They Are Monitored
TRT is not risk-free — no medication is. But the known side effects are well understood, monitorable, and in the vast majority of cases manageable.
Erythrocytosis (Increased Hematocrit)
What happens: Testosterone stimulates red blood cell production. In some patients, this can cause blood to become "thicker" than normal, theoretically increasing thrombotic risk.
Frequency: Approximately 5–20% of patients, depending on formulation and dose. Injectable testosterone tends to cause greater hematocrit elevations than gels due to larger peak-to-trough fluctuations.
Monitoring: Regular complete blood counts. If hematocrit exceeds 54%: dose adjustment, formulation change, or therapeutic phlebotomy (blood donation).
Estrogen Conversion
What happens: The body can convert a portion of testosterone to estrogen via aromatization. When the balance shifts, symptoms may include breast tissue swelling (gynecomastia), fluid retention, or mood changes.
Monitoring: Estradiol levels are checked regularly. If elevated, an aromatase inhibitor may be prescribed to reduce conversion.
Skin Effects
What happens: Testosterone stimulates sebaceous gland activity. Some patients report oily skin or mild acne, particularly during the first few weeks of treatment.
Management: Typically mild and self-limiting. Standard topical skin care usually suffices.
Sleep Apnea
What happens: Evidence suggests TRT may exacerbate existing obstructive sleep apnea. There does not appear to be increased risk in patients without prior history.
Recommendation: Men with known sleep apnea or suggestive symptoms (snoring, daytime somnolence despite adequate sleep) should undergo sleep evaluation before initiating therapy.
The Importance of Medical Supervision
These points underscore one central message: TRT is safe when conducted properly. "Properly" means:
- Rigorous diagnosis — Two laboratory tests on separate days, fasting morning samples, plus clinical symptoms
- Individualized dosing — Targeting the physiological normal range, not the maximum
- Regular monitoring — Blood work every 3 months in years 1–2, then every 6 months once stable
- Therapy adjustment — Dose, formulation, and adjunct medications adapted as needed
- Open communication — Patients must be thoroughly informed about side effects, realistic expectations, and alternatives
What TRT Is Not
It is crucial to distinguish between medical TRT and anabolic steroid abuse:
| Medical TRT | Anabolic Steroid Abuse | |
|---|---|---|
| Goal | Physiological normal range | Supraphysiological levels |
| Dose | 50–100 mg/week (typical) | 500–2,000+ mg/week |
| Monitoring | Regular blood work | None or self-monitoring |
| Substances | Pharmaceutical testosterone | Often multi-compound stacks |
| Prescription | Medical, following diagnosis | Illicit procurement |
| Risk profile | Well characterized, manageable | Significant health risks |
FAQ
Does TRT increase the risk of heart attack? No. The TRAVERSE trial (2023) with over 5,200 participants — the largest randomized study on this topic — showed no increased risk of heart attack, stroke, or cardiovascular death with TRT [1]. Large meta-analyses confirm these findings [2]. The updated EAU 2025 guidelines now affirm the cardiovascular safety of TRT [8].
Can TRT cause prostate cancer? Current evidence shows no association between TRT and increased prostate cancer risk. Morgentaler's saturation model explains why: androgen receptors in the prostate are already saturated at low testosterone levels [3]. Nonetheless, regular PSA monitoring remains part of standard TRT surveillance.
What side effects does TRT actually have? The most common side effects are hematocrit elevation (5–20%), mild acne in the initial weeks, and potential estrogen increase. All of these are manageable with proper monitoring. Serious adverse effects are rare with correctly dosed TRT under medical supervision.
Does TRT cause permanent infertility? No. Sperm production is suppressed during TRT but recovers in over 90% of cases within 12 months of discontinuation [7]. For men with fertility goals, HCG and clomiphene are available as fertility-preserving alternatives.
Conclusion
Research over the past two decades paints a clear picture: testosterone replacement therapy is a safe and effective treatment for documented testosterone deficiency under medical supervision. The longstanding myths about heart attacks and prostate cancer have been refuted by large, high-quality studies.
This does not mean TRT is risk-free — no medication is. But the known side effects are well understood, monitorable, and treatable. The decision for or against TRT should be based on current evidence, not outdated fears.
Further Reading
Specialist in General Internal Medicine · Medical Director
This article was medically reviewed by Dr. Ramadan for accuracy. It is based on current research and international guidelines.
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Sources
- [1]Lincoff AM et al. (2023). Cardiovascular Safety of Testosterone-Replacement Therapy. *N Engl J Med*, 389(2), 107–117
- [2]Corona G et al. (2018). Testosterone and Cardiovascular Risk: Meta-Analysis of Interventional Studies. *J Sex Med*, 15(6), 820–838
- [3]Morgentaler A, Traish AM (2009). Shifting the paradigm of testosterone and prostate cancer: the saturation model and the limits of androgen-dependent growth. *Eur Urol*, 55(2), 310–320