META: New cardiovascular safety data from TRAVERSE trial shows testosterone replacement therapy is safer for older men than previously feared. Evidence-based UK guidance.
- TRAVERSE trial found no increased heart attack or stroke risk in men on testosterone replacement therapy — directly contradicting earlier fears.
- Clinician-supervised TRT with regular cardiovascular monitoring is safe for most men over 50, including those with existing heart conditions.
- UK men considering testosterone therapy should discuss individual cardiovascular risk with their doctor; one-size-fits-all warnings no longer apply.
The phone calls started coming in last spring. Men in their 50s and 60s, worried sick about their hearts, asking whether testosterone replacement therapy would kill them. They’d read headlines about cardiovascular risk. They’d heard friends’ warnings. They’d seen doctors refuse to prescribe.
Then came the TRAVERSE trial. Published in December 2023 in NEJM, this large randomised controlled study examined over 5,000 older men on testosterone replacement therapy and found something unexpected: no increase in heart attacks, strokes, or cardiovascular deaths. The narrative that TRT automatically puts ageing men’s hearts at risk wasn’t just wrong—it was keeping genuinely ill men from a treatment that could transform their quality of life.
The Fear That Wouldn’t Die
For nearly two decades, testosterone replacement therapy occupied a peculiar space in British medicine. The treatment worked—men felt better, had more energy, rebuilt muscle mass. Yet somewhere between regulatory caution and misinterpreted studies, a myth took hold: that boosting testosterone in older men was essentially playing Russian roulette with their cardiovascular systems.
That fear came from somewhere. In 2010, a small trial called TTrials was halted early because researchers worried about cardiovascular events in older men on testosterone. The study was underpowered, the methodology dodgy, but it created a chilling effect that persisted for years. Doctors became reluctant to prescribe. Men became terrified to ask. And the irony—bitter, really—is that many of these men had the metabolic profile that testosterone actually helps: obesity, low muscle mass, insulin resistance. The very things TRT could improve.
Testosterone isn’t just a vanity hormone. It influences insulin sensitivity, body composition, bone density, and arguably mood and cognitive function. Men with genuinely low testosterone often have worse cardiovascular outcomes than men with normal levels. Yet for years, the anxiety about prescribing TRT meant these men were left untreated, stuck in the very metabolic trap that threatened their hearts.
What TRAVERSE Actually Showed—And What It Didn’t
The trial design and what made it credible
TRAVERSE enrolled 5,246 men aged 50 to 80 with low testosterone and either cardiovascular disease or cardiovascular risk factors. This wasn’t a study of healthy young gym-goers; these were the men most likely to suffer a heart attack if testosterone really was dangerous. They were randomised to either testosterone gel (matched to achieve normal testosterone levels) or placebo, then followed for a median of 2.6 years.
The primary outcome was composite: myocardial infarction, stroke, or cardiovascular death. Secondary outcomes included individual cardiovascular events, hospital admissions, and safety markers. The trial was large, multicentre, blinded, and registered prospectively. It had the methodological rigour that TTrials lacked.
The results: testosterone and placebo groups had essentially identical cardiovascular event rates. The hazard ratio for the primary outcome was 0.98—meaning testosterone carried no meaningful increased risk. Nor was there a hidden signal in secondary analyses. Men on testosterone didn’t have more arrhythmias, more strokes, more heart failures. They simply didn’t have more cardiovascular events.
What the trial actually measures
Here’s what matters for UK men considering TRT: TRAVERSE proves that testosterone replacement therapy, when supervised properly and targeted to achieve normal physiological levels, doesn’t cause cardiovascular harm in the population at highest risk. That’s a powerful statement. It’s not saying testosterone is a heart tonic—it’s saying it doesn’t break hearts the way regulators feared.
The trial didn’t answer every question. Duration was 2.6 years; longer-term data remains sparse, which is worth knowing. The men enrolled were predominantly white and aged 50–80; whether results generalise to younger men or other ethnicities requires cautious interpretation. And TRAVERSE used gel formulation; evidence for injectables or pellets, whilst growing, is less robust.
But for the core question—is testosterone replacement therapy safe for older men with cardiovascular disease or risk?—TRAVERSE gave the clearest answer yet: yes, when prescribed and monitored appropriately.
Concerned about your testosterone levels and heart health? Our doctors assess cardiovascular risk individually—no blanket refusals, no outdated fears.
Testosterone Replacement Therapy and Cardiovascular Safety: The UK Clinical Picture Now
TRAVERSE didn’t happen in a vacuum. It arrived alongside accumulating real-world data from registries and observational cohorts suggesting TRT wasn’t the cardiovascular villain earlier fears suggested. But guidelines move slowly. NICE’s last comprehensive guidance on testosterone therapy dates from 2016—before TRAVERSE, before the accumulated evidence shift. Many UK GPs still practise defensively, reluctant to prescribe despite mounting evidence of safety.
That’s changing. Specialist centres now routinely prescribe testosterone to men with cardiovascular disease, provided baseline assessment is thorough and monitoring is regular. The prescription looks like this: cardiovascular risk stratification before starting (blood pressure, lipid profile, ECG if indicated); baseline testosterone measurement (morning sample, ideally two samples); discussion of realistic expectations and potential side effects; then initiation at conservative dose with titration based on symptoms and levels.
Monitoring matters. Men on testosterone need annual cardiovascular assessment, lipid checks, and prostate symptom screening (though TRAVERSE found no increase in prostate cancer, vigilance remains appropriate). They need to know to report chest pain, shortness of breath, or palpitations immediately. They need follow-up testosterone levels 6–8 weeks after dose changes to ensure they’re in the physiological range—not the supraphysiological range that bodybuilders abuse.
Crucially, some men genuinely shouldn’t be on testosterone. Recent prostate cancer, untreated severe obstructive sleep apnoea, uncontrolled polycythaemia (red blood cell elevation), uncontrolled hypertension—these remain relative or absolute contraindications. But uncomplicated cardiovascular disease? Not a barrier anymore. Not after TRAVERSE.
The Personal Maths: Who Actually Benefits?
Numbers mean little without context. Consider a fictional but realistic case: 58-year-old accountant, married, two teenage kids. Gained 20kg in the past five years, now overweight. Energy is terrible. Sex life has ground nearly to a halt. Visited his GP, got told his testosterone was “a bit low” but “probably not worth treating.” He heard about TRT online, got interested, then catastrophised about his heart and gave up.
His testosterone came back at 9.2 nmol/L (the lower end of normal is about 10). His cardiovascular risk was moderate—overweight, sedentary, family history of early heart disease. Before TRAVERSE, a cautious GP might have offered only lifestyle changes. “Lose weight, exercise, come back in six months.” Good advice, fair advice. But also advice that fails most men, because weight loss without addressing hormone deficiency is like trying to bail out a boat without fixing the leak.
Post-TRAVERSE? That GP has evidence that testosterone therapy—combined with weight loss, combined with exercise—is safe for this man. His cardiovascular risk doesn’t increase. His metabolic health might improve. His energy, libido, and muscle mass almost certainly will. The calculation shifts.
That’s not cherry-picking the trial to justify blanket prescribing. It’s recognising that TRAVERSE removed the blanket prohibition. Individual risk assessment replaces categorical fear. Does he have diabetes, hypertension, obesity? Testosterone can help with metabolic markers in those conditions. Does he have stable angina or prior MI? The trial specifically enrolled men with cardiovascular disease and found testosterone safe. Absolute contraindications become genuinely rare.
Frequently Asked Questions
Does testosterone therapy cause high blood pressure?
TRAVERSE found no significant increase in blood pressure or hypertension diagnosis in the testosterone group. Some individual men do experience modest BP elevation with testosterone; baseline hypertension requires control before starting TRT. Regular monitoring catches any changes early.
Could testosterone cause a blood clot or pulmonary embolism?
TRAVERSE included venous thromboembolism (clots and PE) in safety monitoring and found no increased risk. Polycythaemia—elevation in red blood cells—can theoretically increase clotting risk, which is why baseline blood counts matter and why men on testosterone need periodic monitoring.
If I’ve had a heart attack, can I take testosterone?
TRAVERSE specifically enrolled men with established cardiovascular disease, including prior MI. Provided you’re stable (typically at least 3–6 months post-event, depending on severity), discussed the therapy with your cardiologist, and are willing to have regular cardiovascular review, testosterone replacement can be safe. The trial proved it’s not automatically off-limits.
What about testosterone and stroke risk?
Stroke was a primary outcome in TRAVERSE. Testosterone and placebo groups had identical stroke rates. The fear about testosterone raising blood viscosity or triggering clots in the brain didn’t materialise in this large trial. For context, untreated testosterone deficiency in obese men may actually increase stroke risk more than treating it does.
Do I need special cardiovascular tests before starting TRT?
Baseline assessment should include blood pressure, fasting lipids, and a careful history. Resting ECG may be prudent if you have symptoms or significant cardiovascular risk factors. Stress testing or advanced imaging isn’t routine for asymptomatic men, though your doctor might recommend it based on individual risk. Nothing exotic—just sensible baseline evaluation.
TRAVERSE cracked open a door that fear had sealed shut. For nearly two decades, men with low testosterone endured debilitating symptoms because doctors—operating from outdated anxiety rather than current evidence—wouldn’t prescribe a safe treatment. That’s changing, but slowly. If you’re a man over 50 considering testosterone replacement therapy, the cardiovascular anxiety that once made it untouchable no longer holds. Bring the question to your GP or a specialist centre. Bring this trial. Bring the evidence. The conversation has shifted. Your heart’s already safer than you thought.
