There are many types of contraception, but most are geared towards those with ovaries and uteruses. The options for those with testes remain pretty sparse—the choices are basically condoms and vasectomies. But one research team is working to create a non-hormonal male birth control pill, and human trials could start by the end of the year.
The proposed pill contains an experimental compound that blocks proteins from binding to vitamin A, also known as retinoic acid, which is known to be crucial to fertility and virility in mammals. Chemists and pharmacologists at the University of Minnesota hope that blocking vitamin A’s selective compound interactions in cells will create reliable but reversible sterility in humans. The team has already shown that it’s 99 percent effective in preventing pregnancy in mice without known side effects, plus the mice were able to produce offspring normally again 4-6 weeks after they stopped receiving the compound.
Researchers will begin testing human clinical trials in the third and fourth quarters of 2022. But there’s no guarantee that the overwhelmingly positive results in mice will translate to humans. “Of mice and men and the great divide between them. It’s hard to ask a mouse about moodiness or fatigue or other side effects that may manifest in human studies,” Jesse Mills, a male reproductive scientist and director of the Men’s Clinic at UCLA who is not involved with this research, told Healthline. “I am eager to see what the human trials show.”
There are no approved birth control pills for testes-havers on the market, though many oral contraceptive candidates have reached and failed clinical trials. Most have targeted the hormone testosterone. But blocking testosterone can come with side effects like depression, weight gain, and decreased libido. Though, to be fair, birth control pills for women often have all those side effects, on top of others.
Those side effects are often enough to turn people away from those medications, Mills told Healthline. “Our track record as a gender for assuming birth control responsibility is not stellar. Women overwhelmingly outnumber men for going through surgical sterilization procedures even though a female tubal ligation is far more invasive than a vasectomy,” he said.
Circumventing those pesky side effects is exactly why the UMN team is searching for a non-hormonal answer, Md Abdullah Al Noman, a graduate student in medicinal chemistry working on this research, told Gizmodo.
The UMN researchers are aware that their compound is not guaranteed to work in humans. “Because it can be difficult to predict if a compound that looks good in animal studies will also pan out in human trials, we’re currently exploring other compounds, as well,” Gunda Georg, the department head of medicinal chemistry at the University of Minnesota who leads the lab conducting this research, said in a statement.
Another promising male contraceptive is already in the middle of human clinical trials. NES/T lowers sperm and testosterone levels through a gel that is absorbed through the skin of the user’s shoulders and upper arms. Phase 2 trials should be completed by 2023.