In a study, researchers managed to suppress the sperm count of male participants.

Although the results seem promising, the research team still must find the perfect balance of hormones to inject through the vaccine, seeing that hormonal treatment often causes side effects, including depression, acne, and mood disorders.

Man, shot, vaccine.
The “male pill” might become a reality. Image credit: Sostre SN News.

“The study found it is possible to have a hormonal contraceptive for men that reduces the risk of unplanned pregnancies in the partners of men who use it. Our findings confirmed the efficacy of this contraceptive method previously seen in small studies,” stated Dr. Mario Philip Reyes, co-author of the study.

No more IUD, condoms, and pills for monogamous couples

320 men without known infertility issues aged 18 to 45 participated in the study. All of them had been in monogamous relationships with female partners for at least a year. They were subjected to a sperm count test to ensure that they displayed normal levels before the shot was administered.

The participants received a 200mg injection of norethisterone enanthate and 1,000mg of testosterone undecanoate, expected to last for at least six months to reduce their sperm count. They were injected monthly and were asked to provide semen samples in the suppression phase and later in the subsequent phase where they would use common birth control methods.

When the men’s sperm count dropped to less than 1 million spermatozoa per milliliter in two consecutive tests, the couple was prompted to use the shot as their method of birth control, thus testing the effectiveness of the injection in a real-life scenario. The participants continued with the injections and providing semen samples for over a year; then they were asked to stop so their sperm count could recover by itself.

274 of the participants saw a dramatic decrease in their sperm count in 6 months. The male birth control shot was determined to be effective in 96 percent of the participants. The issue was that they presented side effects, which caused at least 60 of the subjects to drop out of the trials. 1,491 cases of side effects were reported, but over 500 of them were not related to the male birth control shot.

One of the participants suffered from severe depression and another suffered from an intentional overdose of acetaminophen. Researchers did not reveal whether these events occurred with the same participant. Another subject suffered from arrhythmia after ceasing to receive the injections.

Even when the side effects appeared to be unavoidable for the current set of trials, 75 percent of the participants reported that they were willing to use the contraceptive method after the trial had concluded.

“More research is needed to advance this concept to the point that it can be made widely available to men as a method of contraception. Although the injections were effective in reducing the rate of pregnancy, the combination of hormones needs to be studied more to consider a good balance between efficacy and safety,” stated Dr. Reyes.

Source: Journal of Clinical Endocrinology and Metabolism