TRT and Heart Health: What the Research Actually Says

For years, testosterone replacement therapy sat under a cloud of cardiovascular uncertainty. A 2010 study (later retracted), a 2014 study in JAMA, and subsequent FDA black box warnings created fear that TRT increased heart attack and stroke risk.

That concern wasn't irrational — observational data was genuinely mixed. But the science has moved significantly since then, and men considering TRT deserve a clear-eyed look at what the evidence actually shows.

The TRAVERSE Trial: The Definitive Answer

In 2023, the New England Journal of Medicine published TRAVERSE — the Testosterone Replacement Therapy for Assessment of Long-term Vascular Events and Efficacy Response in Hypogonadal Men. This was a prospective, randomized, placebo-controlled trial specifically designed to answer the cardiovascular safety question.

Key findings: - 5,246 men with hypogonadism (low testosterone) and increased cardiovascular risk were randomized to daily topical testosterone or placebo - Follow-up: average 33 months - Primary endpoint: major adverse cardiovascular events (MACE) — non-fatal heart attack, non-fatal stroke, or cardiovascular death - Result: No significant difference in MACE between TRT and placebo groups (hazard ratio 0.96, non-inferior)

This was the definitive trial. For men with low testosterone — even those with elevated cardiovascular risk — TRT did not increase the risk of heart attack, stroke, or cardiovascular death.

What TRAVERSE Found (The Full Picture)

Non-inferiority on MACE doesn't mean TRT is cardiovascular-neutral across all endpoints. TRAVERSE found:

Increased risk with TRT: - Pulmonary embolism (blood clots in lungs): small but statistically significant increase - Deep vein thrombosis: small increase - Atrial fibrillation: small increase

No difference: - Heart attack - Stroke - Cardiovascular death - All-cause mortality

Potential benefits (observed but not primary endpoints): - Improved bone density - Improved anemia - Better sexual function and libido - Improved energy and mood

The clot findings are worth taking seriously. Testosterone increases erythropoiesis (red blood cell production), raising hematocrit. Elevated hematocrit increases blood viscosity and theoretically clot risk. This is why hematocrit monitoring is standard practice on TRT.

Why Low Testosterone Itself Is a Cardiovascular Risk

The cardiovascular debate often focuses on whether TRT increases risk. Less discussed: whether low testosterone *is itself* a cardiovascular risk factor.

The evidence here is substantial:

• Visceral fat: Low testosterone is strongly associated with increased visceral adipose tissue, a key driver of metabolic syndrome, insulin resistance, and cardiovascular disease
• Insulin resistance: Multiple studies link low testosterone to impaired insulin sensitivity, independent of obesity
• Endothelial function: Testosterone appears to have direct effects on vascular endothelium, promoting vasodilation
• Lipid profiles: Low testosterone is associated with higher LDL and lower HDL in some studies
• Inflammation: Men with low testosterone show higher markers of systemic inflammation (CRP, IL-6)

From this perspective, treating true hypogonadism isn't adding a cardiovascular risk — it may be correcting one. The key word is "true hypogonadism": symptomatic men with confirmed low testosterone on multiple measurements, not men with normal testosterone seeking enhancement.

The Hematocrit Issue: Managing Polycythemia

The most actionable cardiovascular risk with TRT is hematocrit elevation. Normal male hematocrit is 38.3–48.6%. TRT commonly raises it to 50–55%. Above 54%, most physicians recommend intervention.

Management options: 1. Therapeutic phlebotomy (blood donation): The simplest, most effective intervention. Donating blood quarterly is common on TRT 2. Dose reduction: Lowering testosterone dose often reduces hematocrit 3. Changing route: Injectable testosterone produces higher peak levels and more hematocrit elevation than topical or subcutaneous routes 4. Hydration: Adequate hydration reduces blood viscosity

Marrow monitors hematocrit at standard follow-up labs. If elevated, your physician will discuss the appropriate intervention.

Who Should Not Take TRT

Despite TRAVERSE's reassuring primary findings, TRT is not appropriate for everyone:

• Men with recent (within 6 months) heart attack or stroke
• Men with severe or uncontrolled heart failure
• Men with thrombophilia (inherited clotting disorders)
• Men with extremely elevated hematocrit at baseline
• Men with prostate cancer (absolute contraindication)

For men with stable cardiovascular disease who are candidates for TRT, the TRAVERSE trial provides significant reassurance. The conversation should happen with a physician who knows your full cardiovascular history.

The Balance Sheet

Risks of TRT (genuine, manageable): - Hematocrit elevation → clot risk → mitigated by monitoring and phlebotomy - Small increase in atrial fibrillation - Small increase in pulmonary embolism

Risks of untreated hypogonadism: - Increased visceral fat - Worsened insulin resistance - Reduced bone density - Impaired cardiovascular function - Poor quality of life, depression, sexual dysfunction

For most men with true hypogonadism, the evidence supports that TRT improves metabolic risk factors and carries no significant increase in MACE. The conversation is no longer "does TRT cause heart attacks" — TRAVERSE answered that. The conversation now is individual risk assessment, appropriate monitoring, and managing the specific risks that do exist.

The Bottom Line

The 2014 scare was based on flawed observational data. The TRAVERSE trial — the largest, most rigorous study ever conducted — found TRT does not increase heart attack or stroke risk. Hematocrit monitoring and periodic blood donation manage the most significant residual risk.

Men with low testosterone and cardiovascular concerns shouldn't be categorically excluded from treatment. They should be treated thoughtfully, with appropriate monitoring and a physician who understands the full evidence base.