Birth control that’s as simple as popping a pill might be available for men in the near future. YCT-529, a hormone-free male birth control pill, has moved on to clinical trials in humans after proving it works in animals.

“This is really the first time a non-hormonal contraceptive for men has entered clinical trials,” says Gunda I. Georg, PhD, who is researching YCT-529 and serves as the director for the Institute for Therapeutics Discovery and Development at University of Minnesota. “It’s very exciting to see that this could become a reality.”

Given that this is an experimental medication and involves important elements like your sperm count, it’s fair to have a few questions. Here’s what the research has shown so far, plus why Georg thinks this drug may be on the market in a few years if all goes well.

What did the study find?

The study, which was published in Communications Medicine, analyzed the impact of YCT-529 on male non-human primates and mice.

In the mouse study, the researchers found that the medication caused temporary infertility and was 99 percent effective at preventing pregnancies within four weeks after the mice started taking the drug. In non-human primates, YCT-529 lowered sperm counts within two weeks. The drug also had no side effects in either group.

The results “lay the groundwork” for human clinical trials, the researchers wrote in the study’s conclusion.

How does this pill work?

This gets a little technical, but the drug is a type of medication called a retinoic acid receptor-alpha (RAR-alpha) inhibitor. It prevents sperm production by blocking access to vitamin A, which is an established way to tamp down on sperm counts. “The drug reduces the number of sperm a man produces. Then, when we discontinue the drug, the sperm count returns to normal,” Georg explains.

“The vitamin A pathway is not something that is particularly new,” says Philip Werthman, MD, a urologist and director of the Center for Male Reproductive Medicine and Vasectomy Reversal in Los Angeles, CA. “But by shutting down this receptor, they shut down sperm production. It makes perfect sense. ”

This is a big factor to highlight: Both types of animals got their full fertility back after they stopped taking the drug, although the timelines were different. In mice, sperm counts fully rebounded within six weeks; In non-human primates, it was back within 10 to 15 weeks.

Georg says that researchers can’t do mating studies in monkeys, but they did take sperm counts before, during, and after the animals took the drug, and found similar results to the mouse study.

“That provided really good evidence to suggest that the drug would be efficacious and reversible in humans,” she says.

What else is out there in the male birth control arena?

You probably have some baseline knowledge in male birth control, but a recap never hurt. As of this second, only two male birth control methods exist that are approved by the Food and Drug Administration (FDA): condoms and a vasectomy.

But there are other options being researched right now, including a hormonal gel that blocks sperm production. Research into male birth control options hasn’t been seamless, though. In 2016, the World Health Organization halted a stage 2 study on a hormonal injection to lower sperm counts after an independent review panel found it had too many side effects.

What happens now?

Human clinical trials on YCT-529 started in December 2023, according to Georg. The first trial looked at safety data to see if there were any side effects—“there were none in the 50 men,” Georg says.

Now, the research team is looking into how effective the drug is in men and to confirm that the impact on sperm count is reversible.

It can take a long time to get any medication approved by the FDA, but Georg is hopeful that the process for this one will be a little faster given how clear the results can be.

“We can easily see if the sperm count is reduced and if it goes back to normal,” she says. “You can monitor it so much more easily than some other treatments for things like a chronic disease to say if it works or doesn’t work at a certain dose.”

Georg points out that there’s been a lot of interest in her research, and she’s all for it. “Men are reaching out to participate in the clinical trials. There is a lot of interest and enthusiasm,” she says.

“More and more men want to take responsibility for birth control without necessarily having a vasectomy or any kind of permanent sterilization,” says Dr. Werthman. “There really is no temporary contraception for men, short of condoms. This opens up a whole new avenue.”

Korin Miller is a freelance writer specializing in general wellness, sexual health and relationships, and lifestyle trends, with work appearing in Men’s Health, Women’s Health, Self, Glamour, and more. She has a master’s degree from American University, lives by the beach, and hopes to own a teacup pig and taco truck one day.