TRT and Cardiovascular Risk: What the TRAVERSE Trial Actually Found

For over a decade, testosterone therapy's cardiovascular safety was one of the field's most contested open questions, driven largely by a handful of smaller, methodologically weaker studies that suggested elevated heart attack and stroke risk. TRAVERSE, published in 2023, was designed specifically to settle it with the kind of large-scale randomized data the field had been missing.

Why TRAVERSE Was Different

TRAVERSE enrolled over 5,000 men aged 45-80 with pre-existing cardiovascular disease or elevated cardiovascular risk and confirmed low testosterone with hypogonadal symptoms — a population specifically chosen because it represented the group where a cardiovascular safety signal would be most likely to appear, and most clinically important to detect. Participants were randomized to testosterone gel or placebo and followed for a mean of around 22 months, with major adverse cardiac events (cardiovascular death, non-fatal heart attack, non-fatal stroke) as the primary endpoint — a proper randomized, placebo-controlled, blinded design, a major step up from the retrospective and observational studies that had driven earlier safety concerns.

The Headline Result

TRAVERSE found testosterone therapy was non-inferior to placebo for the primary cardiovascular composite endpoint — in plain terms, testosterone therapy did not increase the rate of heart attacks, strokes, or cardiovascular death compared to placebo in this population over the study period. This was the largest and most rigorous cardiovascular safety data testosterone therapy had ever had, and it did not confirm the risk signal earlier smaller studies had raised.

What TRAVERSE Did Flag

The trial wasn't a blanket all-clear on every front. Testosterone-treated participants had higher rates of atrial fibrillation, acute kidney injury, and pulmonary embolism compared to placebo — secondary findings that are real signals worth monitoring, even though they didn't translate into a difference in the primary cardiovascular composite endpoint. This is why TRAVERSE is best summarized as reassuring on major cardiac events specifically, not as evidence that TRT carries zero cardiovascular-adjacent risk across the board.

Limitations Worth Knowing

TRAVERSE studied testosterone gel, not injectable esters, which are the more common TRT delivery method in current practice — gel produces a flatter, steadier blood-level curve than injections, so how directly the results generalize to injectable protocols with more peak-and-trough variability is a reasonable open question. The trial also enrolled men with confirmed hypogonadism and real symptoms, not a general population using TRT for optimization outside a clinical low-testosterone diagnosis, and the roughly two-year follow-up doesn't capture truly long-term, decade-plus outcomes.

Practical Takeaway

TRAVERSE meaningfully de-risked TRT's core cardiovascular safety profile for hypogonadal men, using the strongest study design the question had ever received — that's a genuine and important result. It also surfaced real secondary risks (atrial fibrillation, blood clots, kidney injury) that warrant monitoring, and it leaves some generalizability questions open regarding delivery method and longer time horizons. Neither 'TRT causes heart attacks' nor 'TRT is cardiovascularly risk-free' fully captures what TRAVERSE actually showed.