For a decade, cardiovascular safety was the most contentious question in TRT. Two observational studies in 2013–2014 suggested increased cardiovascular events with testosterone use. The FDA mandated a safety warning and required a definitive trial. TRAVERSE was that trial — and its results changed the conversation.
TRAVERSE: The Definitive Trial
The Testosterone Replacement Therapy for Assessment of Long-term Vascular Events and Efficacy Response in Hypogonadal Men (TRAVERSE) trial enrolled 5,246 men ages 45–80 with hypogonadism AND pre-existing cardiovascular disease or high cardiovascular risk. This was intentionally a high-risk population — the cohort most likely to show harm if TRT genuinely increased cardiovascular events.
Primary endpoint: First occurrence of death from cardiovascular causes, nonfatal MI, or nonfatal stroke (MACE).
Result: Non-inferiority confirmed. TRT did not increase MACE compared to placebo. The hazard ratio was 0.96 (95% CI 0.78–1.17) — meaning the risk was statistically indistinguishable between groups, with the point estimate actually slightly favoring testosterone.
Key Secondary Findings
- Coronary revascularization: Slightly higher in the testosterone group (HR 1.21) but not statistically significant
- Pulmonary embolism: Slightly higher in the testosterone group (not statistically significant)
- Atrial fibrillation: No difference between groups
- Prostate cancer: No difference between groups
- Acute kidney injury: Slightly higher in the testosterone group
None of the secondary safety signals reached statistical significance, but several trended in the same direction — slightly elevated procedural/thrombotic events. The clinical significance of these trends is debated.
What TRAVERSE Settled
TRAVERSE convincingly demonstrated that TRT at physiological doses does not cause the acute cardiovascular events (heart attacks and strokes) that the earlier observational studies had suggested. The FDA's mandatory cardiovascular warning on testosterone products was revised in light of TRAVERSE data.
What TRAVERSE Didn't Settle
TRAVERSE studied men for a median of 33 months. Long-term cardiovascular effects (5–10+ years) remain unstudied. The trial excluded men with recent MI, stroke, or uncontrolled heart failure — the highest-risk subgroups. And supraphysiological testosterone doses (common in the bodybuilding community but not in clinical TRT) were not tested.
The Bottom Line
Cardiovascular Safety — With Monitoring
TRAVERSE provides the strongest evidence to date that physiological TRT does not increase major cardiovascular events in men with pre-existing cardiovascular risk. This is reassuring but not a carte blanche — hematocrit monitoring, blood pressure tracking, and standard cardiovascular risk management remain important. TRT at physiological doses is cardiovascularly safe. Supraphysiological doses and long-term effects beyond 3 years remain less well-characterized.