The TRAVERSE Sexual Function Study enrolled 1,161 men who reported low libido and followed them for two years. Testosterone produced significantly greater improvement in sexual activity than placebo — a between-group difference of 0.49 acts per day at 6 months and 0.47 at 12 months — and improved hypogonadal symptoms and sexual desire. It did not improve erectile function.[1]
That last clause is the part that gets dropped, and dropping it changes what the trial says.
Desire and erection are different problems
Low libido is a question of drive: wanting sex. Erectile dysfunction is a question of vascular and neurological mechanics: achieving and maintaining an erection. The two travel together often enough that they get discussed as one complaint, but they have different causes and different treatments.
Testosterone acts on the first. The TRAVERSE data is a clean demonstration of exactly that boundary — the hormone moved the desire-and-activity measures and left the erectile measure where it found it.
What the sub-study did
The Sexual Function Study was nested inside the main TRAVERSE trial, drawing from its 5,204 participants.
- Enrolled: 1,161 men from the parent trial who reported low libido — 587 randomized to 1.62% testosterone gel, 574 to placebo gel.
- Parent-trial eligibility: ages 45–80, two testosterone concentrations below 300 ng/dL, hypogonadal symptoms, and cardiovascular disease or increased cardiovascular risk.
- Primary outcome: change from baseline in sexual activity score.
- Secondary outcomes: hypogonadal symptoms, erectile function, sexual desire.
Two features of that design constrain how far the results travel. The sub-study is 1,161 men, not 5,204 — roughly a fifth of the parent trial. And it enrolled men selected for low libido, which is a population already filtered for the symptom being treated.
What it found
Sexual activity: estimated between-group difference of 0.49 acts per day (95% CI, 0.19–0.79) at 6 months and 0.47 (95% CI, 0.11–0.83) at 12 months; omnibus test P = .011. The treatment effect was maintained at 24 months.[1]
Alongside that, testosterone improved hypogonadal symptoms and sexual desire relative to placebo.
And the finding that completes the picture, in the authors' own framing: TRT improved hypogonadal symptoms and sexual desire, but not erectile function, compared with placebo.
The published conclusion states the duration precisely — TRT for 2 years improved sexual activity, hypogonadal symptoms and sexual desire, but not erectile function. Claims that these benefits were demonstrated over four years are not supported by this paper.
How to read the effect size
An improvement of roughly half an act per day is a real, statistically significant difference, and it held across the full two years rather than fading after the first months. It is also a modest absolute change, measured in a group specifically chosen for having low desire to begin with.
Both things are true at once. The honest summary is that testosterone moved the needle on desire and activity in men who had a desire problem, durably, by a moderate amount — not that it transformed sexual function.
What this means clinically
If the complaint is low desire and testosterone is genuinely low on two morning draws, this is among the better-supported reasons to treat. It is one of the few TRT indications backed by a randomized trial of this size with two years of follow-up.
If the complaint is erectile dysfunction, this trial does not support testosterone as the answer. ED has its own workup — vascular risk factors, medications, diabetes, and the PDE5-inhibitor class that is actually indicated for it. Treating an erection problem with testosterone because a level came back low is how men end up on therapy that does not address what brought them in.
If both are present, they may still need separate treatment. The presence of low testosterone does not make ED a testosterone problem.
This sits alongside what the hub covers on low libido after 40 and how long TRT takes to work.
Bottom line
TRAVERSE gave the field its best randomized evidence that testosterone improves sexual desire and sexual activity in hypogonadal men with low libido, sustained over two years. In the same men, over the same period, it did not improve erectile function. Any summary that reports improved erections from this trial has added something the paper does not contain.
References
1 source
- Pencina KM, Travison TG, Cunningham GR, et al. Effect of Testosterone Replacement Therapy on Sexual Function and Hypogonadal Symptoms in Men with Hypogonadism. J Clin Endocrinol Metab. 2024;109(2):569–580. doi:10.1210/clinem/dgad484 · PMID 37589949
Practical questions about membership, labs and using the spray are answered in the Learn Hub FAQ.