Male contraceptive shows promise
Hormone gels applied to skin sink sperm counts
By Nathan Seppa
HOUSTON — Guys might someday have a birth-control option that rivals the pill. Two gels applied to the skin deliver hormones that knock down a man’s sperm count, acting as a male contraceptive, researchers reported June 25 at the Endocrine Society’s annual meeting.
While women have had access to hormone-based contraceptives for decades, men have had few alternatives beyond condoms and vasectomies. In the new trial, scientists randomly assigned 99 men in the Seattle and Los Angeles areas to apply two unlabeled gels to their skin daily. Some men got gels containing testosterone and Nestorone, a synthetic hormone similar to progestin. Others got a testosterone gel and a placebo.
In all, 56 of the men completed at least 20 weeks of the regimen. By the end, 89 percent of men who got the dual hormone treatment saw their sperm counts plummet from about 15 million per cubic milliliter of ejaculate to less than 1 million. What’s more, a majority of those men made no detectable sperm at all, the researchers found.
“Less than 1 million is an arbitrary line, but it’s a threshold that we say is compatible with effective contraception,” said study coauthor Christina Wang, a physician at UCLA. “There was very effective suppression of spermatogenesis.”