A new study accepted to be published in the Journal of Clinical Endocrinology & Metabolism (JCEM) has revealed that hormonal contraception can become a safe and effective form of contraception for men. This method is also reversible, and is achieved by a combination of testosterone and progestin that suppresses sperm production faster and more completely than testosterone alone.

The leader of the study, Associate Professor Peter Y. Liu of the University of Sydney, Australia, said that it can be possible to diminish sperm output to “concentrations that are comparable with reliable contraception in most, but not all men”, and added that “the rate of suppression is comparable to that achieved after a vasectomy.” Testosterone act as a contraceptive, as well as other male hormones, bye creating negative feedback in a man’s reproductive system, suppressing sperm production.

For their study, Liu and his team analyzed all published male hormonal contraceptive studies of at least three months treatments from 1990 to 2006. The analysis revealed that the combination of testosterone and progestin was more effective at suppressing sperm production than testosterone alone. “Progestin co-administered with testosterone increased both the rate and extent of suppression. It also may make long-term hormonal contraception safer by reducing the dose of testosterone needed for maintenance contraception,” said Liu.

Researchers also came to know that Caucasian men suppressed sperm output faster than non-Caucasians, but not as effectively. That was also the case with younger men with lower testosterone levels, although the differences were small. Also, the investigation team found that it is hard to predict which men will respond best to treatment to make the method consistent and reliable.

Liu said that even though the study represents a great progress in the matter, further analysis must be held that take into consideration the different types of progestins and how they react as a contraceptive method.