By Jef Akst | The Scientist | December 21, 2017
The gel, which men rub on their upper bodies daily, delivers synthetic progestin to block the testes from producing normal levels of sperm.
A team led by researchers at the National Institute of Child Health and Human Development (NICHD) plans to start a clinical trial of a male contraceptive gel next April, MIT Technology Review reports. The quick-drying, hormonal gel is rubbed on the upper arms and shoulders daily and can suppress sperm levels for about three days, according to the team. Specifically, a synthetic version of the hormone progestin, called nestorone, reduces testosterone levels to prevent normal sperm production, while a synthetic testosterone serves to maintain the body’s proper hormone balance without inducing the testes to make sperm.
“I am very confident that if men put the gel on every day and apply it correctly, it will be effective,” Stephanie Page, a professor of medicine at the University of Washington and a principal investigator in the trial, tells Tech Review.
The trial will involve more than 400 couples around the world, including in the U.S., the U.K., Italy, Sweden, Chile, and Kenya. Men will be provided with the gel to use at home for at least four months while researchers monitor their sperm levels. Initially, their partners will be instructed to use their own contraception, but if the men’s sperm counts drop below one million per milliliter, the couples will be asked to use the gel as their only form of birth control for a year, Diana Blithe, program director for contraception development at NICHD, explains to Tech Review. “It’s not a lot of effort. It’s just remembering to use it every day.”