Non-Hormonal Male Contraceptive Implant Shows Promise in Two-Year Clinical Trial

The company behind the product said the implant was inserted in a minimally invasive procedure that took about 10 minutes and used local anaesthetic

A groundbreaking male contraceptive implant called Adam has demonstrated the ability to prevent the release of sperm for at least two years, according to early results from a phase 1 clinical trial. Developed by biotech company Contraline, the non-hormonal contraceptive consists of a water-soluble hydrogel that is implanted into the vas deferens—the sperm-carrying ducts—effectively preventing sperm from mixing with semen.

Designed as a reversible alternative to condoms and vasectomies, the Adam implant is intended to break down naturally in the body over time, thereby restoring fertility. Early clinical data shows that the hydrogel successfully blocked sperm release in two trial participants who have reached the 24-month mark, with no sperm detected in their semen. No serious adverse events were reported.

Kevin Eisenfrats, CEO and founder of Contraline, emphasized the significance of this achievement: “Our goal since day one has been to create a two-year-long male contraceptive – that is what the demand is for: a two-year-long, temporary or reversible male birth control. And we have the first data to show that that’s possible.”

The trial included 25 male participants enrolled at staggered intervals, with additional results expected as others reach the same benchmark. The implant procedure is minimally invasive, taking about 10 minutes and performed under local anesthesia, allowing patients to remain awake throughout.

Unlike previous implants that used materials with unknown breakdown timelines or risks of permanent damage to the vas deferens, Adam’s hydrogel is specifically designed to degrade predictably. Although peer-reviewed data is pending, preclinical animal studies and limited human testing suggest that the implant can dissolve over time, and ongoing development aims to enable "on-demand reversal" of the contraceptive.

Eisenfrats likens Adam to an intrauterine device (IUD), stating that men could opt for repeat procedures after each two-year cycle, with at-home sperm testing available to monitor contraceptive effectiveness.

Contraline is preparing for a larger phase 2 clinical trial in Australia later this year, which will include 30 to 50 participants. Experts in reproductive medicine have cautiously welcomed the development. Professor Richard Anderson of the University of Edinburgh noted, “It’s impressive that this looks like something that does actually work, which is great,” acknowledging the potential for both hormonal and non-hormonal male contraceptives in the near future.

However, Anderson and Professor Jon Oatley of Washington State University both cautioned that reversibility data has yet to be released, and the long-term effects of blocking the vas deferens remain uncertain. Oatley also questioned public willingness to adopt such a procedure, suggesting many men may prefer less invasive options like pills or patches.

Despite these concerns, Adam represents a significant step forward in expanding male contraceptive choices and bridging the gender gap in birth control responsibility.