Options for non-permanent male contraceptives are limited to condoms, with no long-term methods currently available.
However, there have been recent advances in developing potentially reversible contraceptive methods that target the vas deferens.
Vasalgel is a gel-like substance that is injected into the vas deferens, the tube that carries sperm out of the testicles, where it forms an impenetrable gel barrier.
Intravas injection of Vasalgel in sexually mature adult male rhesus monkeys was found effective in preventing conception.
Vasalgel is designed to be a reversible and less invasive form of vasectomy and in the latest study was 100% effective at preventing conception. A blob of the gel is injected into the sperm-carrying tube, known as the vas deferens and acts as a long-lasting barrier.
Catherine VandeVoort, of the California National Primate Research Centre and the study’s lead author, said: “Men’s options for contraception have not changed much in decades. There’s vasectomy, which is poorly reversible and condoms. If they knew they could get a reliable contraceptive that could also be reversed I think it would be appealing to them.”
Vasalgel does not interfere with sperm production and hormone levels in the body remain unchanged, meaning such side-effects are not an issue. As with a vasectomy, sperm continues to be produced in the testes, but rather than being ejaculated, it dissolves and is naturally absorbed by the body.
Previous tests in smaller animals showed the procedure could be easily reversed by breaking up the gel using ultrasound.
The findings are reported in the journal Basic and Clinical Andrology.