Researchers working on a contraceptive pill for men have successfully tested a drug that stops sperm activity without any known side effects. 

The study, conducted at the Oregon National Primate Research Centre, administered the drug EP055 to rhesus macaque monkeys. Published in science journal PLOS ONE, details on the experiments showed that EP055 inhibited sperm’s ability to move by attaching itself to sperm protein EPPIN, reducing the fertilization process. 

According to Science Daily, the dosage worked up to around 30 hours without any physical side effects. 18 days after the first dose, complete recovery was shown across all subjects, meaning that, as a form of birth control, it could be totally reversible. 78 hours after the first infusion sperm was moving again.

It will be some time and work before EP055 can be tested on humans, according to scientists. As other studies into other substances take place, it’s hoped a reversible birth control method for men will be available in the next decade. 

It was recently reported that researchers at universities in Washington and California had developed a safe, effective once-daily pill for men that targets parts of the brain that lower sperm count. Side effects include weight gain and changes in cholesterol, and research continues. 

Back in 2016, a male contraceptive injection study was stopped –though the drug proved effective, side effects were major. A large proportion of participants developed mood disorders and suicidal thoughts, while 5 per cent did not regain sperm function.

As of this month (April 2018), clinical trials will begin on the first contraceptive gel, which would block the testes from producing normal levels of sperm. It’ll be four years of trials though before we hear anything concrete from the study.