TRT Heart Risk: What the TRAVERSE Trial Actually Showed

The strongest evidence on TRT heart risk comes from TRAVERSE, a randomized trial of testosterone replacement therapy (TRT) in 5,246 men aged 45 to 80 with confirmed low testosterone and existing or high cardiovascular risk. Men on testosterone gel had heart attacks, strokes or cardiovascular deaths at a similar rate to men on placebo (NEJM, 2023). That is reassuring, but it is not a blanket verdict. The trial tested a gel, not injections, and found other signals.

Key takeaways

• TRAVERSE found testosterone gel noninferior to placebo for heart attack, stroke and cardiovascular death in men with confirmed low testosterone and high cardiovascular risk.
• The testosterone group had more atrial fibrillation, acute kidney injury and pulmonary embolism.
• In 2025 the FDA removed a boxed cardiovascular warning from testosterone labels and added a new warning about increased blood pressure.
• TRAVERSE did not test injections, long-term use or men without confirmed low testosterone.
• Not everyone qualifies, and whether TRT fits you is a clinician's call after a live visit and labs.

TRT heart risk: does testosterone therapy cause heart attacks or strokes?

In TRAVERSE, heart attacks, strokes and cardiovascular deaths occurred at a similar rate with testosterone gel and with placebo in men with low testosterone and high cardiovascular risk. That does not prove testosterone is safe for everyone, and it does not prove it helps the heart.

The main outcome occurred in 182 men (7.0%) on testosterone and 190 men (7.3%) on placebo (Cleveland Clinic Consult QD, 2023). The hazard ratio compares event rates between groups, and 1.0 means equal risk. In TRAVERSE it was 0.96, with a 95% confidence interval of 0.78 to 1.17. Because that range spans 1.0, the small difference was not statistically significant.

TRAVERSE was a noninferiority trial, built to rule out a meaningful increase in risk rather than to show protection. A broader secondary outcome, which added procedures to reopen blocked heart arteries, was also similar between groups. The investigators still cautioned that the results should not justify widespread prescribing to aging men (Cleveland Clinic Consult QD, 2023).

The American Urological Association (AUA) tells clinicians to inform men that low testosterone is itself a cardiovascular risk factor. It also tells them to counsel that no one can say for certain whether testosterone therapy raises or lowers cardiovascular risk (AUA, 2024). For the basics, see how TRT works and how it's evaluated.

What was the TRAVERSE trial, and who was in it?

TRAVERSE was a multicenter, randomized, double-blind, placebo-controlled trial of men with hypogonadism (low testosterone production) and existing or high cardiovascular risk (NEJM, 2023). Double-blind means neither the men nor their study teams knew who got testosterone.

Earlier research gave mixed results on cardiovascular events (Andrology, 2026). A 2015 FDA requirement prompted TRAVERSE, which testosterone manufacturers funded (Cleveland Clinic Consult QD, 2023).

Who qualified (Cleveland Clinic Consult QD, 2023):

• Cardiovascular profile: existing cardiovascular disease, or three or more risk factors such as high blood pressure, diabetes, smoking, stage 3 chronic kidney disease, high hs-CRP (an inflammation marker) or age over 65.
• Confirmed low testosterone: reported symptoms of hypogonadism plus two fasting morning testosterone results below 300 ng/dL, taken at least 48 hours apart.
• Excluded: severe or congenital hypogonadism (testosterone below 100 ng/dL).

Men used either a daily testosterone gel applied to the skin or a matching placebo gel (NEJM, 2023). Study staff adjusted the testosterone group to keep levels in a target range and hematocrit, the share of blood made up of red blood cells, at or below 54%. The placebo group got sham adjustments (Cleveland Clinic Consult QD, 2023). That was research protocol, not individual guidance. Mean treatment lasted 21.7 months and mean follow-up 33 months (NEJM, 2023).

What else did TRAVERSE find?

Three problems were more common with testosterone: atrial fibrillation, acute kidney injury and pulmonary embolism. An honest summary puts them next to the reassuring headline.

Source: Cleveland Clinic Consult QD, 2023

A letter published in NEJM noted that the testosterone group had more nonfatal arrhythmias, including atrial fibrillation, and that atrial fibrillation is an important risk factor for cardiovascular events (NEJM correspondence, 2023).

Retention was the trial's other weak point. About 61% of men in each group stopped treatment early, 20.8% withdrew, and outcome data covered 82.7% of possible follow-up (Cleveland Clinic Consult QD, 2023). When many people stop treatment, differences between groups can blur. That makes the results less certain for steady long-term use.

What TRAVERSE did not test

TRAVERSE answered one question, in one group of men, using one product. Many questions men ask about their own situation fall outside it.

For men considering injections, this is the biggest gap. Injections produce a different pattern of blood levels than a daily gel, and TRAVERSE cannot say whether that changes cardiovascular risk. It is an untested question, not a known risk.

Monitoring is the other gap. The trial chair questioned whether trial-level monitoring happens in general practice or in "low T centers" (Cleveland Clinic Consult QD, 2023). Services that prescribe without confirming low testosterone, skip baseline labs or never recheck hematocrit and blood pressure are working outside the conditions TRAVERSE studied.

Why was the testosterone boxed warning removed in 2025?

In 2025 the FDA required label changes for all testosterone products to reflect new cardiovascular data. Updated labels no longer carry a boxed warning about increased risk of adverse cardiovascular outcomes, and they now include a new warning about increased blood pressure (The Medical Letter, 2025).

Three points keep this in proportion:

1. This was a labeling decision, not a clean bill of health. The same update added a warning.
2. It covers every testosterone product, including injections. That is a regulatory judgment, not trial evidence about injections.
3. Approval stays narrow. Testosterone products are approved for males with conditions linked to deficient or absent testosterone production, and none is approved for low testosterone due solely to aging (The Medical Letter, 2025).

The blood pressure warning applies across the whole class of testosterone products (The Medical Letter, 2025). High blood pressure is one of the main cardiovascular risk factors that can be changed, and a reassuring result on heart attacks does not make it irrelevant. Checking blood pressure before and during TRT is especially relevant for men who already have hypertension.

A European expert panel's position statement, a consensus document rather than a trial, agreed with the FDA changes. It tied cardiovascular safety to appropriately selected patients who are monitored regularly (Andrology, 2026).

What should a clinician check before and during TRT?

Guidelines set out specific checks before starting TRT and specific monitoring during it. They are standard care, not optional extras.

Before starting:

1. Confirm low testosterone. Guidelines call for symptoms or signs plus consistently low levels on repeated fasting morning tests (Endocrine Society, 2018), and the AUA treats below 300 ng/dL as a reasonable cut-off (AUA, 2024). More detail is in this guide to low testosterone symptoms and testing.
2. Measure hemoglobin and hematocrit. Across randomized trials, testosterone raised hemoglobin by a mean of 1.2 g/dL versus placebo (AUA, 2024). Too many red blood cells, called polycythemia, thickens the blood. The 2018 AUA guideline says clinicians should consider withholding testosterone if baseline hematocrit is above 50% until the cause is investigated (J Urol, 2018).
3. Check PSA (prostate-specific antigen, a blood marker of prostate health) in men over 40 (AUA, 2024).
4. Review cardiovascular risk factors such as blood pressure, cholesterol, diabetes and smoking (J Urol, 2018).
5. Screen for reasons not to start. The Endocrine Society recommends against starting testosterone in men with elevated hematocrit, untreated severe obstructive sleep apnea, uncontrolled heart failure, a heart attack or stroke within the past 6 months, breast or prostate cancer or certain prostate findings, severe urinary symptoms, or near-term fertility plans (Endocrine Society, 2018). If fertility matters to you, read how TRT affects fertility.

During treatment:

• Hematocrit is rechecked. Guidelines favor individualized plans with careful monitoring, especially of hematocrit (Andrology, 2026). The AUA treats 54% or higher as the point where the clinician intervenes (J Urol, 2018). That threshold is for your clinician to act on, not a number to manage yourself.
• Blood pressure is now a labeled concern for every testosterone product (The Medical Letter, 2025).
• Given TRAVERSE's signals, a history of blood clots, atrial fibrillation or kidney problems is worth raising with your clinician.

Decisions about format and schedule come from your clinician's guidance and pharmacy instructions, not from an article.

How access works through New Blue

Every New Blue hormone pathway starts with a live clinician visit and lab work, because an intake form cannot do the checks described above. New Blue is a technology and administrative services platform. Medical services are provided by independent licensed clinicians; medications are dispensed only if prescribed.

1. You share your health history, including cardiovascular risk factors, current medications and any history of clots or irregular heart rhythm.
2. You have a live visit with an independent licensed clinician and complete lab work.
3. The clinician decides whether TRT is appropriate. Not everyone qualifies. Eligibility depends on your history, labs and clinical review, and that's how it should work.
4. If prescribed, a licensed partner pharmacy ships the medication directly to you. Follow-up labs follow your clinician's plan.

The injectable, cream and oral testosterone protocols all use this live-visit-plus-labs model. Availability varies by state, so check state availability. Care is for adults 21 and older. New Blue is not for emergencies: chest pain, sudden shortness of breath, one-sided weakness or a swollen, painful leg need emergency services right away.

Consultation timing varies by clinician availability. If treatment isn't appropriate, refunds follow our refund policy. For current pricing and details, see the injectable testosterone protocol.

Frequently Asked Questions

Is injectable TRT riskier for the heart than testosterone gel?

TRAVERSE tested only a daily gel, so it cannot answer that directly. The FDA's 2025 label changes cover all testosterone products, including injections, but that was a regulatory decision rather than trial evidence about injections. A licensed clinician weighs format against your history and labs.

Did the FDA remove the boxed warning on testosterone?

Yes. In 2025 the FDA removed the boxed warning about increased risk of adverse cardiovascular outcomes from testosterone labels, and the same update added a warning about increased blood pressure (The Medical Letter, 2025). Check the current label for any specific product.

Does testosterone therapy protect the heart?

Current evidence does not show that it does. TRAVERSE was designed to rule out a meaningful increase in heart attack, stroke and cardiovascular death, not to show benefit. Low testosterone is linked to higher cardiovascular risk, but that does not mean treating it lowers risk.

Can I take TRT if I have heart disease?

It depends, and the decision is a clinical one. TRAVERSE enrolled men with existing cardiovascular disease, but the Endocrine Society recommends against starting testosterone within 6 months of a heart attack or stroke, or with uncontrolled heart failure. A licensed clinician weighs your history, labs and current treatment before deciding.

Does TRT raise blood pressure?

It can. Updated labels for all testosterone products now include a warning about increased blood pressure (The Medical Letter, 2025). Blood pressure belongs in baseline and ongoing checks, especially for men who already have hypertension.

What should I ask a prescriber about TRT and heart health?

Ask whether low testosterone will be confirmed with repeated fasting morning tests, and whether hematocrit, PSA and blood pressure will be checked before and during treatment. Ask how a history of blood clots, atrial fibrillation or kidney problems will be handled. A prescriber who cannot answer clearly is not working to the standard guidelines describe.

Sources

1. Cardiovascular Safety of Testosterone-Replacement Therapy. The New England Journal of Medicine, 2023. https://pubmed.ncbi.nlm.nih.gov/37326322/
2. TRAVERSE Study Supports Cardiovascular Safety of Testosterone Therapy When Used as Indicated. Cleveland Clinic Consult QD, 2023. https://consultqd.clevelandclinic.org/traverse-study-supports-cardiovascular-safety-of-testosterone-therapy-when-used-as-indicated
3. In Brief: Label Changes for Testosterone Products. The Medical Letter on Drugs and Therapeutics, 2025. https://doi.org/10.58347/tml.2025.1726d
4. Evaluation and Management of Testosterone Deficiency (2024). American Urological Association, 2024. https://www.auanet.org/guidelines-and-quality/guidelines/testosterone-deficiency-guideline
5. Evaluation and Management of Testosterone Deficiency: AUA Guideline. Journal of Urology, 2018. https://doi.org/10.1016/j.juro.2018.03.115
6. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. The Journal of Clinical Endocrinology and Metabolism, 2018. https://pubmed.ncbi.nlm.nih.gov/29562364/
7. Cardiovascular safety of testosterone therapy: Insights from the TRAVERSE trial and beyond. A position statement of the European Expert Panel for Testosterone Research. Andrology, 2026. https://pmc.ncbi.nlm.nih.gov/articles/PMC12670475/
8. Cardiovascular Safety of Testosterone-Replacement Therapy (correspondence). New England Journal of Medicine, 2023. https://doi.org/10.1056/NEJMc2309389

Medical disclaimer: This article is educational and is not medical advice. Treatment decisions are made by a licensed clinician based on your history, evaluation and lab results. New Blue Health is a technology and administrative services platform, not a medical provider.