A functional male hormonal birth control may be just around the corner

After decades of work, researchers say they are finally making progress on a hormonal birth control option for men that is long-acting and reversible.

The product getting researchers excited is a hormonal gel that men rub on their shoulders once daily. Once used consistently, the gel blocks sperm production in a male’s testes.

The gel was developed by the National Institutes of Health and the nonprofit Population Council and uses a similar process to female birth control pills.

The gel uses two hormones to achieve its desired effect: nestorone, a progestin, and testosterone, the male sex hormone.

The nestorone works to suppress the production of testosterone in the testes and, with it, the development of sperm. Meanwhile, the testosterone in the gel replaces that which is lost to help the body maintain muscle retention, libido, and other necessary functions it provides. But at the same time, it doesn’t give enough to get someone pregnant.

Researchers have worked to find the right dosage and concentration for almost two decades. But now, in the latest batch, they think they got it right.

Diana Blithe, a program director for contraception development at the NIH National Institute of Child Health, spoke with KCBS Radio about the product, saying it follows much of what other similar products already do.

“It goes on the shoulders, which is perhaps a surprise, but that’s where testosterone gel that’s used therapeutically for men is applied,” Blithe said. “And it’s the easiest place to be able to cover up to avoid exposure to a partner during intimate contact.”

As for where the product is now, Blithe says it’s beginning its efficacy trials right now.

“It’s in contraceptive efficacy trials right now, which means that we’re trying it out in couples who are actually at risk of pregnancy. And it’s working better than we thought it would,” Blithe said. “It’s working faster than we thought it would. And so I am hopeful that when all the data of this ongoing trial are finally analyzed and published, that we can find out what the FDA would like to see for a phase three program.”

While normal sperm counts range from 15 million to 200 million sperm per milliliter of semen, studies have shown sperm counts of less than 1 million per milliliter are low enough to stave off a potential pregnancy.

In a clinical trial, 86% of men achieved the low target for sperm counts within 15 weeks of using the gel. However, some participants saw results work even faster, leaving researchers excited about the possibility.

“The gel seems to work really well, but if it’s delivered orally, it’s cleared really quickly and would have to be given in multiple doses per day,” Blithe said. “So we have found that the gel is giving a very nice daily dose. That doesn’t cause a lot of fluctuations. That would have other problems if it were going up and down rapidly.”