A new male contraceptive is showing promise in mice. 

A new single-dose, on-demand, temporary male contraceptive that “stops sperm in its tracks” has proven effective in early mammal studies, according to US research.

Male contraceptives are currently limited to condoms and vasectomy. Although there have been multiple efforts to develop additional male contraceptives, these efforts have been limited by low efficacy, long pre-treatment times, or negative side effects.

But researchers in the US have developed optimised soluble adenylyl cyclase (sAC) inhibitors that show strong potential as on-demand male contraceptives.

The drug inhibits an enzyme that is essential for sperm mobility.

In recent mouse studies, a single dose was found to be 100 per cent effective in preventing pregnancy for two the first two hours, and 91 per cent effective for the first three, without affecting normal mating behaviour. 

After 24 hours, the mice had returned to normal fertility levels, and no negative effects were observed when the drug was administered continuously for six weeks.

While the authors administered these drugs via injection in most experiments, they found that mouse sperm motility was also reduced by similar levels upon oral administration. 

They note that further research is needed to determine whether these drugs will work effectively in humans and to identify any potential side effects.

The full study is accessible here.