Male contraceptive: New gel for men rubbed on the shoulders once a day developed by researchers

A daily contraceptive gel for men which is applied to the shoulders has shown promise in early trials. Photo / 123RF

A daily contraceptive gel for men which is applied to the shoulders has shown promise in early trials.

The product, which is rubbed on both shoulder blades daily, has been found to lower sperm counts in around eight weeks.

Scientists say this is quicker than other similar products in development and could overcome a limitation of other male hormonal contraceptives.

The product contains two hormones, Nestorone (segesterone acetate) and testosterone, and is currently being tested as part of a clinical trial on more than 200 men in the US.

The gel is rubbed into the shoulders or shoulder blades because it is easy to reach for the user and it is also unlikely a child or woman would come into direct contact with the gel in this location.

The hormones soak into the skin and are absorbed by the bloodstream and accidental exposure to the gel could cause premature puberty in children and acne or excessive hair growth in women.

Phase two results announced on Sunday at the Annual Conference of The Endocrine Society in Boston, US, reveal the product reached low sperm levels in 80 per cent of men after just 12 weeks.

Contraception-level effectiveness is considered to be when a millilitre of semen contains less than one million sperm, according to scientists.

More than half of men reached this level by eight weeks, quicker than other experimental male contraceptives that can take as long as four months to become effective.

“More than 80 per cent of participants using this novel male hormonal contraceptive gel formulation containing Nestorone 8mg and Testosterone 74mg showed suppressed sperm output within 12 weeks, a rate that appears to be faster than prior studies with other hormonal regimens,” the authors from the National Institutes of Health in the US write in their study.

“A more rapid time to suppression may increase the attractiveness and acceptability to potential users.”

Participants had their sperm count measured every four weeks and the scientists say this may have missed key data between four and eight weeks that could indicate the method is even more effective than the current figures show.

The treatment works because testosterone lowers sperm suppression itself, but the segesterone product also speeds this up.

The trial launched in 2018 and scientists at the time said the project could help share the responsibility of contraception between men and women.

Dr Diana Blithe, the project lead on the Contraceptive Development Program at the National Institutes of Health in Maryland, said at the time that the product had been in development for more than a decade.

“We are hopeful that the NES/T gel study will demonstrate effectiveness of a male method for use by couples.

“A successful result may lead to additional scientific discovery around contraceptive products for men.”

A non-hormonal form of male contraception is also in development and is currently being investigated in some British men.

The drug, called YCT-529, deactivates a protein called retinoic acid receptor alpha (RAR-alpha) which inhibits vitamin A activity and therefore curtails sperm production.

This approach avoids using hormones such as testosterone which has raised concerns among prospective users.