On May 11, 2026, JAMA Internal Medicine published results from the SPIRIT trial showing that testosterone replacement therapy meaningfully improved sexual desire, sexual activity and physical function in men who had undergone surgery for prostate cancer — a population long told that testosterone was off-limits. The randomized, placebo-controlled study, led by Shalender Bhasin of Mass General Brigham's Division of Endocrinology, Diabetes and Hypertension, enrolled 136 androgen-deficient prostate-cancer survivors at Johns Hopkins Hospital and Brigham and Women's Hospital.

Why It Matters

Prostate-cancer survivors are a large, underserved slice of the men's sexual-health market that telehealth TRT brands and urology practices have mostly avoided for liability reasons. A peer-reviewed trial showing short-term safety and real sexual-function gains gives clinicians cover to treat a group they previously turned away — and gives the testosterone-prescribing industry, from Hims' Testosterone Rx+ to specialty men's-health clinics, a clinical foundation to expand into it. It also reinforces the increasingly evidence-backed message that low libido is a treatable hormonal condition, not just an inevitable cost of cancer treatment.

Participants received weekly testosterone injections or placebo over a 12-week treatment window, followed by 12 weeks of observation. Men on testosterone reported significantly higher sexual activity and desire, better quality-of-life scores, improved body composition and stronger aerobic performance than the placebo group. Notably, erectile function itself did not change — underscoring that libido and erection are distinct problems requiring distinct treatments.

The headline finding is about safety as much as efficacy. A prior prostate-cancer diagnosis has historically been treated as a hard contraindication for testosterone, on the long-standing theory that the hormone fuels tumor regrowth. In SPIRIT, no participant in either arm experienced biochemical recurrence (a PSA rise signaling cancer's return) during the study. Bhasin cautioned that the window was short and called for longer follow-up before the contraindication is broadly relaxed.

The data arrives amid a broader regulatory thaw around testosterone in the U.S. An FDA expert panel recommended descheduling testosterone in December 2025, and an April 2026 Federal Register notice opened a pathway toward an approved low-libido indication for testosterone therapy. SPIRIT adds rigorous clinical evidence precisely as policymakers and telehealth prescribers reconsider who should have access.

Sources

Update — 2026-05-29

Initial entry — story first created.