Promising male contraceptive pill works in 30 minutes, wears off in a day


Male contraceptives have traditionally been limited to condoms or vasectomies, which aren’t ideal solutions for many reasons. Now scientists have demonstrated a promising new method that takes the form of a pill that can be taken just before sex, greatly reducing fertility for 24 hours.

For decades women have shouldered much of the responsibility of contraceptives thanks to “the pill”, but a male equivalent continues to elude science. Past attempts keep turning out to be ineffective, have too many side effects, take a long time to kick in or wear off, or some combination of these.

But a new drug, developed by scientists at Weill Cornell Medicine, seems to solve all those problems. It works by targeting a protein called soluble adenylyl cyclase (sAC), which is vital for sperm function. That makes the drug a sAC inhibitor, and we’re not sure whether that pun is intended or not. Previous studies have found that mice and men who naturally lacked the gene for sAC were infertile but otherwise healthy, so the team set out to investigate whether blocking it worked as a contraceptive.

In tests, the scientists gave male mice a single dose of a sAC inhibitor called TDI-11861, and let them loose with the ladies. The inevitable occurred, but even after 52 mating attempts not a single female mouse fell pregnant. In contrast, the control group impregnated about a third of the females.

Importantly, the researchers say the drug was quick to work, inhibiting the mice’s sperm within 30 to 60 minutes, and remained 100% effective for up to two and a half hours. By the three-hour mark, some sperm began to regain their motility, and after 24 hours the mice were essentially back to full fertility.

If those results carry across to humans, this has all the makings of a very useful male pill. If a date seems to be going well you could, say, head off to the bathroom after dinner to discreetly pop the pill, and be confidently covered for the night’s activities. It could be a one-off thing when you think you might get lucky, or it could be a daily regimen – after all, the team found no negative effects after giving the mice these drugs continuously for six weeks.

That flexibility makes it a more appealing option than other experimental male contraceptives, which can take weeks to reduce fertility or regain it if you want to start trying for children. And taking a pill is less invasive than getting a gel injected into your vas deferens.

The research was published in the journal Nature Communications.

New Atlas, 14 February 2023