The drug, called 11-beta-MNTDc, was tested on 40 healthy volunteers – 30 of whom took the medicine in different doses (14 men 200 milligrams a day and the other 16 volunteers 400 mg a day) for 28 days. 

A second control group was given a simple placebo instead. The molecule is a derivative of testosterone which has both progestin characteristics, which prevent the formation of the spermatozoon, and characteristic “balancing”, capable of maintaining secondary sexual characteristics.

The test only served to establish the safety of the drug, the authors of the Los Angeles Biomedical Research Institute explain, but the lowering of hormones bodes well for the efficacy of the “pill”. “Our result – explains Dr. Christina Chung-Lun Wang, head of the study – suggests that the pill, which combines two hormonal activities into one, will decrease sperm production while preserving libido”.



Among the men who received 11-beta-Mntdc, the average level of circulating testosterone dropped to a minimum. Five men reported a decrease in sexual drive, and two described mild erectile dysfunction, but sexual activity did not decrease. Furthermore, no participant was forced to stop taking the drug due to serious side effects. The effects were reversible after treatment interruption.

Before coming to conclusions, the researchers stressed the importance of completing a second trial. The drug, in fact, before it manages to optimally influence sperm production requires 60 to 90 days. A test lasting just 28 days is therefore not totally reliable: longer studies will therefore be necessary to reach conclusions. If the results of the first test are confirmed, it will be possible to move on to a wider experiment and, only later, to tests on sexually active couples.