Research from the Contraceptive Development Programme at the US National Institutes of Health (NIH) has found that a newly developed male contraceptive gel combining testosterone and the synthetic hormone nestorone, ‘suppresses sperm production faster than similar experimental hormone-based methods for male birth control.’
It was also reported that the gel lowers sperm count ‘to effective contraceptive levels within an average of eight weeks. This is significantly quicker than the nine to 15 weeks typically required for male contraceptive injections to take effect.’
The trial is reported to have involved 222 men ‘who applied 5ml of the gel, approximately a teaspoon, on each shoulder blade daily.’
NBC News reports that after 12 weeks of applying the gel every day, 86% of trial participants achieved sperm suppression, ‘meaning they had only up to 1 million sperm per millilitre of semen, the amount the researchers deemed effective for contraception. On average, the timing for effective contraception was eight weeks.’
‘In comparison, normal sperm counts without contraception can range from 15 million to 200 million per millilitre.’
Clinical trials on the development of the male contraceptive gel were initiated in the US in 2018 when research funded by the National Institutes of Health (NIH) in collaboration with the Population Council and NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD).
Study investigator Diana Blithe and chief of NICHD’s Contraceptive Development Program said at the time that:
“Many women cannot use hormonal contraception and male contraceptive methods are limited to vasectomy and condoms. “A safe, highly effective and reversible method of male contraception would fill an important public health need.”
Similar trials were developed in Scotland in 2019 involving eighty men in Manchester and Edinburgh
Richard Anderson, a professor of clinical reproductive science at the University of Edinburgh, who was leading the study, said at the time that the method was expected to be more effective than condoms, which in real-life conditions are about 82% effective:
“We’re aiming to get it down to the sort of level you get with the pill which is a very small but not zero failure rate,” he said.