Scientists who have discovered a cell route, or switch, that prevents sperm from being able to swim claim that an on-demand, non-hormonal male contraceptive pill may actually be a reality.
According to studies done on mice, it keeps sperm shocked for at least a few hours, which is enough time for them to cease moving toward the egg.
It is intended to do many more tests, first on rabbits and then on humans.
The concept is that users might take a pill an hour prior to having sex and watch the time to see when it wears off.
How does it work?
Unlike the female contraceptive pill, it does not involve any hormones.
is a cellular signalling protein called soluble adenylyl cyclase or sAC. The experimental male pill inhibits or blocks sAC.
- We are using male contraceptive gel
- male pill
In the early study in mice, funded by the US National Institutes of Health and published in the journal Nature Communications, a single dose of the drug, called TDI-11861, immobilised sperm before, during and after mating.
The effect lasted for around three hours. By 24 hours, it appeared to have fully worn off with the next batch of sperm swimming normally.
One of the scientists, Dr Melanie Balbach from Weill Cornell Medicine in New York, said it showed promise as a reversible, easy-to-use contraceptive.
If it does ultimately work in humans, men might be able to take it only when, and as often, as needed. They could make day-to-day decisions about their fertility.
But it would not protect against sexually transmitted infections, experts warn. Condoms would be needed for that.
Prof Allan Pacey, professor of andrology at the University of Sheffield, said: “There is a pressing need for an effective, reversible, oral contraceptive for men and although many different approaches have been tested over the years, none has yet reached the market.
“The approach described here, to knock out key enzyme in sperm that is critical for sperm movement, is a really novel idea. The fact that it is able to act, and be reversed, so quickly is really quite exciting.
“If the trials on mice can be replicated in humans with the same degree of efficacy, then this could well be the male contraceptive approach we have been looking for.
“They have done some tests on human sperm in the laboratory and it works in exactly the same way. So that, I think, really does open up the prospects that we can have some human trials.”
By inhibiting a protein on the surface of sperm, other researchers have been investigating a slightly different approach to stop sperm swimming.
