More than 60 years after the female contraceptive pill became available, men who want to take control of contraception have two options – use a condom, or have a vasectomy. Like truly bezel-less smartphones though, we’ve been touted a male birth control pill for decades, with not much to show for it.
But wait! Something more concrete is finally happening – two hormone-free pills are now being tested in humans, and they take completely different approaches. Here’s how close the male pill really is…
What is the male birth control pill?
First things first – there isn’t one definitive male birth control pill waiting to be approved. Instead, the term more broadly covers several experimental drugs that are designed to provide reversible contraception without a condom or vasectomy.
Previous candidates have used hormones to switch off the signals controlling sperm production. This can work, but altering those hormones can cause side effects, including acne, weight gain, and mood changes. Nothing fun there. Researchers must also provide enough testosterone to maintain sex drive and other functions without restarting sperm production.
The two pills attracting attention in 2026 are non-hormonal. The first, YCT-529, interferes with the production of sperm, while NLS-133 aims to change what happens during ejaculation.
They’re not equally well established, however. YCT-529 has published results from animal studies and an initial human safety trial. NLS-133 only entered a 10-person Phase 2a trial in December 2025, and there aren’t any peer-reviewed results showing that it works.
What is YCT-529 and how does it work?
Sperm production depends partly on retinoic acid, a substance made from vitamin A. YCT-529 blocks one of the receptors it binds to inside the testes, interrupting the signals needed to make sperm without affecting testosterone.
The effect wouldn’t be instant. Someone taking YCT-529 would have to wait for their existing sperm supply to fall below a reliably contraceptive level. Normal sperm production would also take time to recover after treatment stopped.
In preclinical research published in Communications Medicine, four weeks of treatment made YCT-529 99 per cent effective at preventing pregnancies in mouse mating trials, and fertility returned within six weeks of stopping it. The drug also reduced sperm production in six non-human primates, with their sperm counts recovering within 10 to 15 weeks.
It’s absolutely important to reiterate that the 99 per cent figure isn’t a human effectiveness rate. It shows us that the idea works in mice, but there’s a long way to go before that translates to any successful or viable end product.
Has YCT-529 been tested on men?
Yes, although its first human trial was designed to establish basic safety and see how the body processed the drug, not whether it prevented pregnancy.
Sixteen healthy men who had already undergone vasectomies received single doses ranging from 10mg to 180mg. Using vasectomised participants allowed researchers to begin testing it without risking their future fertility.
According to the peer-reviewed Phase 1 results, YCT-529 didn’t produce any serious adverse events or measurable changes to testosterone, heart rate, inflammatory markers, sexual desire, or mood. There was one potentially drug-related incident involving a short period of irregular heartbeats, though. Some of the irregular activity appeared before the highest dose was given, making the cause unclear, and a subsequent examination found nothing requiring treatment. It will, of course, still need more observations in larger trials.
Overall, while the results sound promising, it’s very important to note that this was one dose given to just 16 people. It can’t tell us what will happen when men take the drug repeatedly for months or years.
YCT-529 has since moved into a Phase 1b/2a study in men who produce sperm, with different stages testing repeated use for 28, 90, and 180 days. Developer YourChoice Therapeutics says researchers have observed reduced sperm counts, but detailed results haven’t been published and independently assessed. No trial has established how reliably it prevents pregnancies in couples.
Is there a male birth control pill that works faster?
For those who require a faster solution, NLS-133 approaches the problem from the other end. Rather than stopping the production of sperm over several weeks, it’s being developed as an “on-demand” contraceptive – aka taking a pill shortly before sex to provide temporary protection. It doesn’t mean taking something afterwards, like emergency contraception, and it wouldn’t require weeks of daily treatment before becoming effective.
NLS-133 reportedly combines two drugs already approved in the US – silodosin, which is normally used to treat an enlarged prostate, and guanfacine, which can be prescribed for ADHD and high blood pressure.
Its precise mechanism hasn’t been explained in peer-reviewed research, but it’s thought to interfere with the nerve signals and muscular contractions that transport sperm during ejaculation. Rather than stopping the testes from producing sperm, the aim is to prevent most or all of it from entering the semen temporarily. Developer NEXT Life Sciences says the pill is intended to provide around 24 hours of protection. That’s a target, mind, not a proven duration.
The registered Phase 2a study involves 10 healthy men. Each receives a single dose of NLS-133, another active drug, or a placebo either 90 or 180 minutes before providing a semen sample. Researchers then measure semen volume, sperm count, motility, and shape, as well as noting any changes to orgasm and ejaculation.
But while this should all show whether NLS-133 produces the intended short-term effect, it won’t tell us how reliably it prevents pregnancy. Seeing the pattern? Welcome to the glacial-paced world of pharmaceutical research. Although I’m rather glad they’re not rushing this stuff. Aren’t you?
Do male birth control pills have side effects?
Drugs that interfere with the muscles involved in ejaculation can result in little or no semen emerging, despite the person still experiencing an orgasm. Semen can sometimes travel backwards into the bladder instead, known as retrograde ejaculation. Changes to ejaculation are already a recognised side effect of silodosin.
As a result, an effective pill would need to reduce sperm enough to prevent pregnancy without making sex unpleasant or causing unacceptable side effects. This explains why the study asks about the quality of participants’ orgasms and ejaculations, rather than analysing their samples alone.
It’s also too early to assume that taking it 90 minutes before sex would be the final instruction. Researchers still need to establish exactly when it should be taken, how long any effect lasts, and how quickly normal ejaculation returns.
As for other potential side effects, the honest answer for both pills is that we simply don’t know yet.
YCT-529 is designed to avoid disrupting testosterone, which could reduce the risk of side effects involving mood, libido, muscle mass, and body composition. None of these appeared after a single dose, but the study was too small and short to identify uncommon or long-term problems. Researchers must also confirm that blocking part of the vitamin A signalling system doesn’t cause unwanted effects elsewhere.
NLS-133 combines drugs whose individual side effects are already known. Silodosin can cause ejaculation changes, dizziness, and low blood pressure, while guanfacine can cause sleepiness, dizziness, and reduced blood pressure.
That doesn’t prove their combination will cause the same problems, though. Equally, approval for treating an enlarged prostate, ADHD, or high blood pressure doesn’t automatically make a drug suitable for healthy men to use as contraception.
The safety bar is particularly high, because users would otherwise be healthy and could take the drug for years. Even relatively minor side effects may be difficult to justify when established alternatives exist.
Are there any alternatives?
The most advanced reversible male contraceptive in development is actually a hormonal gel called NES/T. It combines Nestorone, which suppresses the signals responsible for sperm production, with testosterone to maintain normal functions elsewhere. Men apply it to their shoulders and upper arms every day.
NES/T has completed a global Phase 2b trial involving 462 couples, and planning for Phase 3 is under way. Earlier data showed that 86 per cent of the men studied reached the trial’s contraceptive sperm-count target within 15 weeks, with a median time of eight weeks among those who responded. Detailed results from the completed trial are still being analysed.
An implanted hydrogel called ADAM is also being tested. It’s injected into the vas deferens to block sperm from entering semen, effectively acting as a temporary vasectomy. Early results suggest it can block sperm for at least two years, although the human evidence remains limited and its reversibility hasn’t yet been demonstrated.
In other words, the first major new male contraceptive may not be a pill at all.
When will a male birth control pill be available?
That’s the multi-billion-dollar question, isn’t it? At the time of writing, there’s no reliable launch date for either male birth control pill candidate discussed above.
YCT-529 must show that it suppresses sperm reliably, remains safe during prolonged use, and allows fertility to recover. It will eventually need to be tested in couples to find out how often pregnancies occur during real-world use, followed by much larger Phase 3 trials and regulatory reviews.
NLS-133 is even less established. Its current study is an early test of whether one dose alters semen and sperm as expected. It hasn’t been shown that it can prevent fertilisation or pregnancy.
Even if everything goes unusually smoothly, either pill is likely to remain several years away. Suggestions that one could arrive by the end of the decade should be treated as an ambition, not a confirmed release date.
For now, condoms and vasectomy remain the only established contraceptive methods controlled directly by men. The difference in 2026 is that scientists are testing two distinct pills in people – one that gradually stops sperm from being made, and another intended to stop most of it from being released.
Neither is ready for the bathroom cabinet yet. But after decades of waiting, at least the male pill could finally become more than a contraceptive for mice.
