Before a sperm fertilizes an egg, it faces a long journey. Propelled back and forth by its tail, it must swim through the female reproductive tract to the fallopian tube where it meets an egg. Can medical science stop swimmer’s urge? Turns out, yes. An experimental compound called TDI-11861 temporarily inhibits an enzyme that drives sperm, thereby impeding their movement. Therefore, coitus between a man and a woman of reproductive age does not result in pregnancy. The effect of the substance lasts up to two and a half hours. After about three hours, some sperm begin to move again, and by 24, almost all resume their normal movement. Professor of pharmacology at New York’s Weill Cornell Medicine College, Lonnie Levin, defines the substance as an on-off button for sperm in the male body. Since it was assumed that before intercourse, love partners would not want to inject the substance, an oral version was also tried, which gave the same result. This method of impregnation control does not involve hormones, such as are contained in the contraceptives that women take. The idea of ??a non-hormonal contraceptive is that it can be taken shortly before sex, not every day. Levin and his collaborator Jochen Buck, also a professor of pharmacology at Weill Cornell, did not initially set out to find a male contraceptive. They studied a regulatory enzyme called soluble adenylyl cyclase, or sAC, which is found in almost every cell. Depriving the male individuals of it, they become infertile for a certain time. The enzyme appears to play a major role in activating the sperm’s ability to swim. The off-target discovery has given researchers an incentive to develop a potential male contraceptive by designing compounds that can block sAC. But because this enzyme is present elsewhere in the body�and may be needed for other cellular functions�they don’t think it would be a good idea to turn it off permanently. The downside is that the experimental compound loses its effect once it enters the female reproductive tract. So they continue to test compounds that would keep the sperm immobile. Over time, they refined the TDI-11861. The drug does not appear to interfere with sexual functioning or cause side effects. And most importantly, the sperm count is back to normal a day later. The current compound wears off too quickly, which could lead to unwanted pregnancy if not taken at the right time, so pharmacologists hope to extend the window of effectiveness to about 18 hours. In addition, a number of research and analysis phases will be required before it can be put into human use. References: Lonny R. Levin & etc. On-demand male contraception via acute inhibition of soluble adenylyl cyclase. Nature Communications – https://www.nature.com/articles/s41467-023-36119-6