Birth control pill for men that temporarily stops sperm — without hormones — passes safety trial
A first-of-its-kind male birth control pill just cleared its first human safety test, raising hopes that it could soon open the door to a new era of contraception.
The drug, YCT-529, is currently enrolled in a larger clinical trial, with experts hoping it'll be ready to hit the shelves by the end of the decade. Here's everything you need to know about this potential pregnancy game-changer.
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4 The development comes as condom use among men is declining.
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What is YCT-529?
Unlike traditional birth control pills that disrupt hormones, this experimental pill from YourChoice Therapeutics temporarily halts sperm production without affecting testosterone levels.
It works by blocking a protein called retinoic acid receptor alpha, which plays a key role in the sperm making process.
The best part: Early evidence suggests it's totally reversible.
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Does the pill work?
In tests on male mice, YCT-529 sharply reduced sperm production, causing reversible infertility within just four weeks.
When treated males mated with females, the drug proved 99% effective at preventing pregnancy.
Similar results were seen in male non-human primates, whose sperm counts dropped within two weeks of starting treatment.
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4 If approved, the pill could provide men with more control over their reproductive health.
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Notably, both animals fully regained fertility after stopping the drug, with mice recovering within six weeks and primates within 10 to 15 weeks.
No side effects were reported in either group.
Is it safe for humans?
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So far, so good.
The first human trial testing the drug involved 16 healthy men between 32 and 59 — all of whom had previously undergone vasectomies, a surgical procedure that cuts and blocks the tubes that carry sperm from the testicles to prevent pregnancy.
This extra precaution was necessary because no non-hormonal male contraceptive had ever been tested in humans before. Researchers wanted to avoid any risk of permanently affecting fertility, just in case participants wanted to father children later, Nadja Mannowetz, co-founder and chief science officer of YourChoice Therapeutics, told Scientific American.
The goal wasn't to test effectiveness but to see if the drug was well tolerated and to measure how it built up in the body, she explained.
4 The contraceptive had no major side effects when tested in male animals and humans.
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After testing multiple doses, researchers didn't find any concerning side effects, including no changes in heart rate, hormone levels, inflammation, sexual function or mood.
That's notable, because hormonal contraceptives have previously been linked to side effects like mood swings, libido loss, weight gain and acne.
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Across all doses, scientists also 'saw good and quick bioavailability,' meaning the drug stayed active in the body without breaking down too fast, Mannowetz noted.
Why do we need a male birth control pill?
'Studies and surveys continue to show that men want to share the burden of pregnancy prevention with their partners,' Akash Bakshi, CEO of YourChoice Therapeutics, said in a statement. 'But they have just one non-permanent contraceptive option — condoms — and it's 170 years old.'
Across the country, the rate of unintentional pregnancy is nearly 50%. While female contraception offers a variety of options — including pills, implants, injections and devices — vasectomies remain the only reversible male birth control method approved by federal regulators.
4 Currently, women bear the majority of the burden for contraception.
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However, the success of vasectomy reversal procedures varies widely from person to person, and the longer the time since the procedure, the lower the success rate tends to be.
While condoms are available, studies show that men are increasingly not using them.
Several promising reversible male birth control candidates are currently in development and undergoing clinical trials, but most rely on hormonal methods, which carry a higher risk of side effects.
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'A safe and effective male pill will provide more options to couples for birth control,' Gunda Georg, chemist and pharmacist at the University of Minnesota, which is collaborating on the drug with YourChoice Therapeutics, said earlier this year.
'It will allow a more equitable sharing of responsibility for family planning and provide reproductive autonomy for men,' he continued.
What's next for YCT-529?
The drug is now being tested in a larger trial with over 50 men who either had vasectomies or made the decision to opt out of fatherhood.
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Participants will take the pill daily for 28 and 90 days at different doses, while researchers monitor safety and see how well it shuts down sperm production.
The trial is expected to wrap up by mid-2026 — and if all goes well, the first male birth control pill could be just a few years away from hitting the medicine cabinet.
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