A daily gel applied to the shoulders may offer a new option for male contraception, according to early clinical trial results. The treatment, which combines testosterone with a synthetic hormone, successfully lowered sperm counts in a group of 222 men, but researchers have not yet demonstrated that it prevents pregnancy.
The phase 2 trial, conducted by the Population Council, a global non-governmental organization, and funded by the United Kingdom's National Institutes of Health, tested the gel on men aged 18 to 50. Over the course of the study, participants applied the gel once daily to their shoulder blades. By the end of the initial phase, sperm counts dropped to below one million per milliliter of ejaculate—a threshold considered viable for contraception by medical standards. For context, the average male produces between 15 and 200 million sperm per milliliter.
Participants reported minimal side effects. Logan Whitehead, a 24-year-old trial participant from California, described the gel as similar to hand sanitizer in both look and smell. He noted that aside from some acne and weight gain—which he attributed partly to a less active job—he experienced almost no adverse effects. Whitehead, whose partner had struggled with side effects from female birth control, said he would continue using the gel if it receives regulatory approval.
Next Phase: Testing Effectiveness in Real-World Use
The upcoming phase of the trial will involve committed monogamous couples who will rely on the gel as their only form of contraception for a full year. This step is critical to determine whether the reduced sperm count translates into actual prevention of pregnancy. The gel contains Nesterone, a synthetic hormone already used in the Nuvaring vaginal contraceptive ring, alongside testosterone.
If the treatment proves effective and gains approval from the U.S. Food and Drug Administration, it could provide an alternative to existing male contraceptive options, which currently include vasectomy and condoms. However, researchers caution that the results so far only indicate a reduction in sperm count, not proof of contraceptive efficacy.
The trial's outcomes are being closely watched by reproductive health experts, as a reversible, hormone-based male contraceptive has been a long-sought goal. The gel's daily application and relatively mild side-effect profile may make it more acceptable to users compared to other experimental approaches.
