Male Birth Control: New Pill Lowers Testosterone but Preserves Libido

The Pill revolutionized women’s reproductive health when it was approved in 1960, but it has its downsides: weight gain, mood swings, and tender breasts, to name a few. Some critics have raised an important point: Why should females bear the burdens of birth control when males are complicit in the kind of intercourse that risks pregnancy, too? Promising research on male birth control reveals a new compound that could help even out this inequality — and not scare men off in the process.

In a presentation at the Endocrine Society’s annual meeting in New Orleans on Monday, Dr. Christina Wang of the Los Angeles BioMed Research Institute announced that her team’s trial of a male birth control compound called 11-beta-MNTDC not only decreased a hormone linked to sperm production in a 28-day trial of 40 men but also preserved their libido.

There isn’t much point in using birth control as contraception if you don’t want to have sex. Unfortunately, research on male contraceptives tends to run into this problem, study co-investigator Stephanie T. Page, Ph.D., a professor of medicine at the University of Washington School of Medicine, tells Inverse.

“Any time we administer sex hormones in men or women (testosterone or estrogen), there will be effects on libido,” she says. “In some of those studies, as in this one, mild changes were reported in a minority of men.”

But the majority of the men in this study didn’t report any effect on sex drive. What makes 11-beta-MNTDC unique in this regard is its double function, which could allow it to decrease sperm production while sidestepping a mood-killing drop in libido.

Two hormones lead to the production of sperm, explained Wang in her presentation: luteinizing hormone and follicle stimulating hormone. To prevent sperm production — and unwanted pregnancy — you want to suppress the function of these two hormones. The problem is that these two hormones also lead to the production of testosterone, which is important in maintaining male sex drive.

The new drug, 11-beta-MNTDC (full name: 11-beta-methyl-19-nortestosterone dodecylcarbonate), does suppress those two hormones, but it also plays the role of a testosterone mimic. In that way, it is like “a pill with two hormone actions in one,” said Wang.

So, even though the body isn’t producing as much testosterone, 11-beta-MNTDC supplied in pill form makes the body act as though nothing has changed. Importantly, testosterone is involved in sperm production, but Page points out that their testosterone mimic “is not concentrated enough in the testes to support sperm production.”

The men, said Wang, “do not complain of loss of sexual drive mainly because 11-beta-MNTDC is a male hormone that supports all the target organs of testosterone.”

The study was a small one, involving 10 controls who received a placebo drug and 30 men who received either a 200-milligram or 400-milligram dose of 11-beta-MNTDC. After taking the drug or placebo once a day for 28 days, the researchers collected the results: All of the men who took the drug had reduced testosterone levels. Only five men reported mildly decreased sex drive and two reported mild erectile dysfunction, but nobody reported decreased sexual activity.

Importantly, they didn’t measure sperm production — only the level of testosterone, which is directly related to it. That’s because the drug would take at least 60 to 90 days to start affecting sperm production, and so the 28-day study period was too short.

“This is a very early study, and thus we will need to see if changes in libido with this pill are observed in the larger studies that we hope will follow,” says Page.

There are still a few kinks to work out, like the fact that this pill would take four to eight weeks to kick in and that it must be taken with food. But when it does happen — Wang predicts hormonal male contraception will be available in 10 years — it will provide a much-needed option in a very limited field.

“The overall goal of our work in developing male hormonal contraceptives is to create a menu of contraceptive choices for men (pill, injection, implant, gel), similar to the choices of method that women have,” says Page. By providing an alternative to condoms, vasectomy, and withdrawal, she and her co-investigators hope to get more men to use birth control — and prevent more unplanned pregnancies in the process.

Perhaps the reason male birth control is worth pursuing is because changes in US policy are threatening to curtail the availability of hormonal contraceptives for women. The Affordable Care Act, which provides access to no-cost contraceptives for millions of women, could be struck down by President Trump’s Justice Department if the coalition of states appealing a ruling to invalidate it fails. Whether future healthcare policies will treat male and female birth control the same way, however, remains to be seen.