- Scientists are making headway in developing an oral nonhormonal birth control pill for men.
- The first human clinical trial for the drug, YCT-529, recently passed a key safety test. A smaller trial had shown promising results in 2024, paving the way for more rigorous research.
- Other studies in mice and primates found that the male oral contraceptive effectively prevented pregnancy without significant side effects.
Scientists are closing in on the first-ever birth control pill for men.
YCT-529, the first hormone-free birth control for males, was determined safe and effective in its first human trial in 2024. Although the trial was small, with only eight male participants in each of the two cohorts, the results were promising enough to greenlight the drug for further studies in humans.
Now, YCT-529 has passed an important safety test in a second human clinical trial and could soon debut as the first nonhormonal oral birth control pill for men. The results were published on July 22 in
The trial included 16 healthy males ages 32 to 59 who had previously undergone a vasectomy, which was a precaution researchers took to avoid any permanent impacts of the drug on their fertility.
In the first clinical trial of its kind, a nonhormonal oral contraceptive that reversibly stops sperm production has just been deemed safe for human use. The nonhormonal oral contraceptive is a once-daily pill designed to block a vitamin A metabolite in the testes to restrict the production of sperm.
The trial only assessed for safety and didn’t examine the overall effectiveness of blocking sperm production, however. YourChoice Therapeutics, the manufacturer of the drug, is currently conducting more trials to determine this effect.
YCT-529 was cleared for human clinical trials after a long-term study in mice and primates determined its safety and effectiveness.
Those findings, published earlier this year in
The drug reduced sperm counts in male primates within two weeks. The mice and primates fully regained fertility after discontinuing the drug, and no side effects were reported.
“We’re one step closer to delivering the world’s first male birth control pill,” YourChoice Therapeutics chief science officer Nadja Mannowetz, said in a news release last year.
“While the road to FDA approval for any new drug candidate is long, we’re very pleased with the speed, efficiency, and enthusiasm for YCT-529’s first-in-human study. The findings are powerful validation that YCT-529 is safe and well tolerated in men and lays a favorable foundation for further studies,” Mannowetz continued.
YourChoice Therapeutics collaborated with Columbia University to develop the contraceptive YCT-529.
The latest research builds on preliminary evidence that was presented at an American Chemical Society meeting in 2022. Those results also indicated that YCT-529 effectively prevented pregnancy in mice.
The contraceptive also sterilized mice without side effects. The same mice were then able to impregnate other mice four to six weeks after they had stopped receiving the drug.
“Scientists have been trying for decades to develop an effective male oral contraceptive, but there are still no approved pills on the market,” researcher Md Abdullah al Noman had said in a news release about the study.
Noman added that the researchers wanted to develop a form of birth control for males without side effects.
Male contraceptives tested in clinical trials often target the male sex hormone testosterone, which can lead to adverse events, including:
- depression
- weight gain
- increased LDL cholesterol
Michael Eisenberg, MD, a professor of urology and male infertility at Stanford, said part of the challenge in creating an oral contraceptive for men is targeting a precise location within the the reproductive tract.
“You have to find a target and you want to make it specific to the reproductive tract in some way, shape, or form, and really not have any off-target effects,” he told Healthline in an earlier interview.
“The testicle itself is supposed to be an immuno-privileged site. So what that means is sometimes it can be hard to target a medication there specifically… the way the testicle is situated… the way that our body has developed a way to create sperm really limits what can get into that area,” Eisenberg explained.
As human trials with nonhormonal male birth control are underway, it remains to be seen whether the results in mice and primates will translate to the broader human male population.
“Of mice and men and the great divide between them. It’s hard to ask a mouse about moodiness or fatigue or other side effects that may manifest in human studies,” Jesse Mills, MD, director of the Men’s Clinic at UCLA, told Healthline in an earlier interview. “I am eager to see what the human trials show.”
Current birth control options for men include male condoms, vasectomy, or abstinence.
Condoms aren’t always effective and are single-use. Vasectomy is a surgical procedure, and reversals can be expensive, and the results are not always guaranteed.
By contrast, there are numerous birth control options for women, such as:
“In women, there are lots of barrier methods because there are more options in the female reproductive tract to either block egg release or sperm transport. In men, you either have to snip sperm at the source with a vasectomy or plug the exit point with a condom,” Mills said.
Mills explained that part of the reason a male oral contraceptive took so long to develop is likely due to the potential side effects, as well as hesitancy from males to take it.
“The main barrier is finding an effective pill with minimal side effects and the enthusiasm for men to take such a pill. In committed relationships, this will work out well and men will likely be up for taking a pill,” he said.
“But, our track record as a gender for assuming birth control responsibility is not stellar. Women overwhelmingly outnumber men for going through surgical sterilization procedures, even though a female tubal ligation is far more invasive than a vasectomy,” Mills noted.