healthHealth and Medicine

First In-Human Trial Begins For Hormone-Free Male Birth Control Pill

Testing of YCT-529 is expected to continue through to mid-2024.

Holly Large - Editorial Assistant

Holly Large

Holly Large - Editorial Assistant

Holly Large

Jr Copy Editor & Staff Writer

Holly is a graduate medical biochemist with an enthusiasm for making science interesting, fun and accessible.

Jr Copy Editor & Staff Writer

Edited by Maddy Chapman

Maddy is a Editor and Writer at IFLScience, with a degree in biochemistry from the University of York.

close up of man putting a pill in his mouth

Condoms and vasectomies are currently the only contraceptive options for sexually active men.

Image credit: Pixel-Shot/

After successful preclinical studies in mice, researchers have this week begun the first human trials of a hormone-free male birth control pill.

YCT-529, the drug being tested, is the first of its kind to reach Phase I clinical trials. Whilst scientists have been working away for decades in an attempt to create contraceptive options for sexually active men beyond condoms and vasectomies, those that have reached later clinical trial stages have been hormonal. 


Disrupting hormones can come with all sorts of unpleasant side effects, such as mood changes and acne, making YCT-529 a potentially far more appealing option. “The world is ready for a male contraceptive agent and delivering one that’s hormone-free is simply the right thing to do given what we know about the side effects women have endured for decades from The Pill,” said Gunda Georg, who led the development of the pill alongside YourChoice Therapeutics, in a statement.

The new pill works by inhibiting retinoic acid receptor-alpha (RAR-alpha). This is a protein in a family of nuclear receptors that bind to retinoic acid, a derivative of vitamin A that plays a role in sperm formation. By blocking this pathway, YCT-529 consequently prevents sperm production.

In preclinical studies conducted in mice, this approach proved to drastically drop sperm count and was 99 percent effective at preventing pregnancy. Significantly, it was also demonstrated to be safe, and its effect on fertility reversible.

The researchers will be hoping to achieve that same level of success in human studies. The Phase I trial aims to investigate the efficacy of the pill, as well as its safety and tolerability in two cohorts of eight male volunteers. It’s estimated to finish around mid-2024 and even if all goes according to plan, you won’t necessarily be getting YCT-529 from your doctor anytime soon; further trials and clinical approval can take years.


Nevertheless, if it does arrive, there’s likely to be a captive audience – according to a YouGov survey, a third of sexually active men in Britain would be willing to take a male pill and other estimates put the figure as high as 82.3 percent. Not to mention, there’s money to be made, with estimates putting the value of a new male contraceptive method at between $40 to $200 billion.

“While significant work lies ahead, we believe YCT-529’s first human study is a significant step toward a future where both men and women have the power to decide and control contraceptive use, pregnancy, and childbearing,” said Heather Vahdat, executive director of the Male Contraceptive Initiative. “A kind of health equity we believe is long overdue.” 


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