The rubber may be hitting the road if a new gel for men proves effective in preventing pregnancies.
The National Institutes of Health is funding an experimental study to evaluate the effectiveness of a gel that could be used as a male contraceptive, replacing condoms and vasectomies.
The gel, called NES/T, includes the progestin compound segesterone acetate (brand name Nestorone), in combination with testosterone.
It is applied to the back and shoulders and absorbed through the skin.
The progestin blocks natural testosterone production in the testes, reducing sperm production to low or nonexistent levels, officials said.
The replacement testosterone maintains normal sex drive and other functions that are dependent on adequate blood levels of the hormone, according to medical experts.
Researchers plan to enroll about 420 couples to test the gel.
“Many women cannot use hormonal contraception and male contraceptive methods are limited to vasectomy and condoms,” said Diana Blithe of NIH’s Institute of Child Health and Human Development.
“A safe, highly effective and reversible method of male contraception would fill an important public health need.”
Male volunteers will use the NES/T gel daily for 4 to 12 weeks to determine whether they tolerate the formula without side effects.
If sperm levels have not adequately declined, they will continue to use the formulation for up to 16 weeks.
Those participants whose sperm levels drop significantly will be evaluated using the gel for 52 weeks.
The couples will rely on the male gel as the sole method of contraception during that time.
Males will remain in the study for observation for an additional 24 weeks after they stop using the gel to check for side effects.
Segesterone acetate is also used in female hormonal contraception.
The study will be conducted at the Los Angeles Biomedical Institute/ University of California Los Angeles Medical Center and University of Washington in Seattle.