Key takeaways
- In the 2023 TRAVERSE trial of 5,246 high-risk men, testosterone therapy did not raise heart attacks, strokes, or heart deaths.
- It did show small increases in atrial fibrillation, blood clots, and short-term kidney injury, so screening and monitoring matter.
- Untreated low testosterone has its own downside: worse body composition, blood sugar, and metabolic health.
- Therapy is for men with confirmed low testosterone and symptoms who are screened first and monitored, not every aging man.
If you have low testosterone and clear symptoms, but a doctor told you testosterone therapy is "too risky for your heart," you may be working from old information. A large 2023 trial directly tested that worry, and the answer changed the conversation.
Why the heart worry existed
Back in the early 2010s, a couple of weaker studies hinted that testosterone might raise heart-attack risk, and the FDA added warning labels. The trouble was that those studies couldn't separate the therapy from the company it keeps. Low testosterone tends to travel with obesity, diabetes, and sleep apnea, which all hurt the heart on their own. To settle it, doctors needed a proper randomized trial (one where men are assigned by chance to treatment or placebo). That trial was TRAVERSE.
What TRAVERSE found
TRAVERSE enrolled men 45–80 with confirmed low testosterone plus existing heart disease or high heart risk. These were exactly the patients doctors were nervous about. Half got testosterone gel, half a placebo (an inactive look-alike gel), followed for about two years. The result: testosterone did not increase major heart events (heart attack, stroke, or heart-related death). In plain terms, in the men most likely to have a problem, it didn't cause one.
It wasn't a total all-clear, though. The testosterone group had small increases in three things: atrial fibrillation (an irregular heartbeat), blood clots in the legs or lungs, and short-term kidney injury. None of these cancel the main finding. They're the reason testosterone should be a monitored medical treatment, not a vending-machine supplement. The full how-it-works is in testosterone therapy: what your doctor never told you.
Told TRT is off-limits for your heart?
A 30–45 minute consultation with the full pre-TRT screen (testosterone, SHBG, hematocrit, PSA) and cardiologist coordination, with the $35 applied toward your plan.
Book your $35 first visit Call (734) 436-3357
The other side: untreated low testosterone isn't "safe" either
Low testosterone tends to come bundled with insulin resistance (when your cells stop responding well to insulin), belly fat, higher blood pressure, and worse cholesterol. All of these are hard on the heart. Testosterone is metabolically active. When it's low, men lose muscle, gain visceral (deep belly) fat, and their blood sugar drifts the wrong way. So the real question isn't "therapy vs. nothing risky." It's this: for this specific man, which path is safer long-term? Untreated low testosterone with its metabolic slide, or carefully monitored treatment? For many men, the answer is monitored treatment. This connects to the bigger picture in why your labs look normal but you feel terrible and fatigue after 40.
Who is a candidate, and how we keep it safe
A good candidate is a man with low testosterone confirmed on two morning tests, real symptoms, and no dealbreakers. Dealbreakers include:
- active prostate cancer
- a very recent heart event
- untreated severe sleep apnea
- a strong clotting history
Before starting, we run a full screen: testosterone and free testosterone, SHBG (the protein that binds your hormones), estrogen, blood count, kidney and metabolic labs, and PSA (a prostate blood test) over 40. We coordinate with your cardiologist when your heart history calls for it.
Then monitoring keeps it safe. We recheck at 6–12 weeks and every few months after. The big one is your red-blood-cell count (hematocrit). Testosterone can thicken the blood, and if it climbs too high we lower the dose, change the form, or draw off a unit of blood. What I see in clinic: the men who do best are the ones who get screened properly and actually keep up with monitoring. That's where the safety lives.
Frequently Asked Questions
My cardiologist said no to testosterone years ago. Has that changed?
The evidence has changed a lot. The 2023 TRAVERSE trial, the largest of its kind in men with low testosterone and heart risk, found no increase in major heart events versus placebo. Your specific case may still have reasons to be cautious. But a flat "never, because of your heart" is generally not where the field is now. A fresh, coordinated review is reasonable.
I have atrial fibrillation. Can I still consider it?
It's not an automatic no. But because TRAVERSE found a small rise in atrial fibrillation, it changes the conversation. The decision should be made together with your cardiologist, with a clear plan to watch your heart rhythm.
I had a heart attack two years ago. Can I be evaluated?
Likely yes. Stable heart disease, including after a heart attack with good follow-up care, was included in TRAVERSE. Very recent events or unstable heart disease are reasons to wait until you're stable. Your cardiologist should be part of the plan.
Does testosterone therapy raise stroke risk?
TRAVERSE found no increase in stroke or heart-related death versus placebo in properly selected, monitored men.
Why is the blood-count test so important?
Testosterone boosts red blood cell production, which can thicken the blood and, in theory, raise clot risk. We monitor your hematocrit and adjust if it climbs too high. Gel and pellet forms tend to thicken the blood less than injections, but all forms need monitoring.
Will treating low testosterone help my heart long term?
It usually improves muscle, body fat, blood sugar, and cholesterol, all good for the heart. Whether that directly prevents heart events isn't proven. But steadying the metabolic slide that drives risk is a real benefit for many men.
The next step
If you have low testosterone, real symptoms, and a heart history that's made therapy feel off-limits, the right next step is an up-to-date evaluation, not a one-line answer. Book your $35 first visit or call (734) 436-3357. Arbour Longevity is at 2217 Packard St #15, Ann Arbor, MI 48104, open Thursday through Monday, 10am to 7pm.
References
- Lincoff AM, Bhasin S, Flevaris P, et al. (2023). Cardiovascular Safety of Testosterone-Replacement Therapy (TRAVERSE). New England Journal of Medicine 389:107-117.
- Bhasin S, Brito JP, Cunningham GR, et al. (2018). Testosterone Therapy in Men With Hypogonadism: Endocrine Society Guideline. JCEM.
- Mulhall JP, Trost LW, Brannigan RE, et al. (2018). Evaluation and Management of Testosterone Deficiency: AUA Guideline. J Urol.
- Hackett G. (2024). Cardiovascular safety of testosterone replacement therapy: a review of TRAVERSE. Trends in Urology and Men's Health.
This article is educational and does not replace individualized medical advice.
Gandhi Bhattarai, FNP-BC, PMHNP-BC, Anti-Aging/Functional Medicine BC
Triple board-certified nurse practitioner and founder of Arbour Longevity in Ann Arbor. Every article is written from clinic practice and reviewed against current guidelines.
✓ Medically reviewed · Last updated August 21, 2026
How we reviewed this article
Arbour Longevity articles are written by the treating clinician, checked against primary sources (peer-reviewed journals, FDA labeling, Endocrine Society and other specialty guidelines) and re-reviewed when guidance changes. See our editorial policy. Spotted an error? Email info@arbourlongevity.com.
This article is educational and is not a substitute for individualized medical advice. Whether a treatment is appropriate for you is determined during consultation.
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