Cardiovascular Safety of Testosterone-Replacement Therapy

TRAVERSE (Testosterone Replacement therapy for Assessment of long-term Vascular Events and efficacy ResponSE in hypogonadal men) is the randomized, double-blind, placebo-controlled cardiovascular outcomes trial that addressed the central safety question hanging over testosterone replacement therapy for two decades. Investigators enrolled 5,246 men aged 45–80 with at least one symptom of hypogonadism, two morning fasting total testosterone levels below 300 ng/dL, and either pre-existing cardiovascular disease or high cardiovascular risk. Participants were randomized to daily transdermal 1.62% testosterone gel (dose-titrated to maintain serum testosterone in the 350–750 ng/dL range) or matching placebo gel. Mean duration of treatment was 21.7 months; mean follow-up extended to approximately 33 months. The trial was multicenter, conducted across 316 sites in the United States, and sponsored by AbbVie under an FDA postmarketing requirement.

The primary endpoint was the first occurrence of major adverse cardiovascular events (MACE) — a composite of cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke — assessed for non-inferiority of testosterone versus placebo at a pre-specified hazard-ratio margin of 1.5. The primary endpoint occurred in 182 of 2,596 men in the testosterone group (7.0%) and 190 of 2,602 men in the placebo group (7.3%); the hazard ratio was 0.96 (95% confidence interval 0.78–1.17), and the trial met its non-inferiority criterion. Cardiovascular death, non-fatal MI, and non-fatal stroke individually moved in the same direction as the composite — no signal toward harm. The TRAVERSE result is the most definitive cardiovascular-safety reading of testosterone replacement available as of 2026 and the data point that recalibrated the field after years of cohort-study controversy.

The secondary-endpoint pattern is the part of the trial that requires careful editorial handling. Several pre-specified non-MACE outcomes occurred at higher rates in the testosterone group. Atrial fibrillation occurred in 3.5% on testosterone versus 2.4% on placebo. Acute kidney injury occurred in 2.3% versus 1.5%. Pulmonary embolism occurred in 0.9% versus 0.5%. These differences did not feed into the primary composite endpoint, the trial was not specifically powered for each individual secondary endpoint, and the absolute event rates are small — but the pattern is consistent across three separate endpoints and the directionality is biologically plausible (testosterone-driven erythrocytosis, hematocrit elevation, and pro-thrombotic shift). The headline framing "TRAVERSE was reassuring for cardiovascular safety" is correct for the primary endpoint; the more careful framing is "TRAVERSE was reassuring for cardiovascular safety on the prespecified composite while identifying signals for atrial fibrillation, pulmonary embolism, and acute kidney injury that warrant clinical attention." Both framings appear in the post-publication literature.

For the andropause-and-peptides dossier, TRAVERSE supplies the cardiovascular-safety benchmark against which the HPG-axis-preserving alternatives (hCG, clomiphene, enclomiphene, kisspeptin, pulsatile gonadorelin) are compared and is, currently, the only such benchmark in the broad field. There is no equivalent large RCT for any peptide-based alternative to testosterone replacement. The mechanistic case that endogenous-pathway testosterone production (where Leydig cells produce testosterone under hCG or LH stimulation, with intratesticular testosterone preserved) should yield a cleaner cardiovascular signal than exogenous transdermal testosterone is plausible but unproven; TRAVERSE establishes the bar that an equivalent trial of an HPG-axis-preserving approach would need to clear for outcome-level comparability. See the TRT discontinuation playbook for the recovery-trajectory considerations in men exiting exogenous therapy.