It has taken quite some time – but a male contraceptive ‘pill’ may finally soon be a reality.

More than half a century since the first female pill was approved for use in the UK, scientists are at last testing a range of options that could mean men no longer have to rely solely on condoms and vasectomies. Options include a gel that’s rubbed onto a man’s shoulders, and an ‘after dinner’ daily pill.

In the most recent advance, revealed in April, scientists announced a major breakthrough in the development of a gel that is injected into the sperm ducts (or vas deferens) to block the release of sperm into a man’s semen.

Called Adam, the water-based gel implant is inserted under local anaesthetic in a procedure that takes less than 30 minutes. Results of a recent trial in 25 young men in the US, conducted by manufacturer Contraline, showed the gel blocked sperm release.

It’s thought to last about two years before it starts to break down and is flushed out of the body as waste. At that point, the maker says, a man can have another gel injection if he wants. The company claims there are no significant side-effects, but it’s not yet clear how easy it is to remove the gel surgically (rather than wait for it to biodegrade) if a patient wants to stop using it – for instance, if circumstances change and he and his partner want to start a family.

A larger, international trial is now being planned to see if the early findings can be replicated.

‘It’s promising but it’s still at a very early stage,’ says Tet Yap, a consultant andrological surgeon at Guy’s and St Thomas’ NHS Foundation Trust in London.

Another alternative is a gel that’s rubbed on a man’s shoulders or upper arms once a day.

An after-dinner ‘daily’ pill doesn’t target testosterone directly, so it is hoped to be free from side effects

Called Nestorone, it contains a combination of segesterone acetate (a synthetic female sex hormone) and testosterone.

Segesterone acetate reduces the activity of gonadotropins, hormones that stimulate the production of sperm. As this can also cause a drop in the testosterone produced by the testicles (potentially reducing libido and causing erectile problems, muscle weakness and hot flushes), testosterone is also included.

The gel gets absorbed into the bloodstream and travels to the testicles.

A study last year by the US National Institutes of Health showed that 86 per cent of the 222 men using the gel reached the accepted point of contraception (defined as one million or fewer sperm per millilitre of semen) after 15 weeks of daily use. (A normal sperm count is anything from 15 million to 200 million per millilitre.)

‘This is the one that most people in the field of reproductive medicine are most excited about,’ says Mr Yap.

‘There have been a few trials already and we’re waiting for the results of one more later this year on its effectiveness and how well a man’s fertility recovers when he stops taking it – that’s the big question. But if the results of that are positive, Nestorone could be available to men in the UK within a year or so.’

However, it takes at least three months of daily use before a man’s sperm has fallen sufficiently to prevent conception, so Nestorone isn’t suitable as short-term birth control.

Meanwhile, a team at the University of Minnesota in the US is working on a contraceptive pill for men that doesn’t work on interfering with the body’s normal hormone balance to achieve birth control. Code-named YCT-529, it blocks the effects of a protein called RAR-alpha, which plays a crucial role in sperm formation.

Consultant andrological surgeon Tet Yap says Nestorone could be available to men in the UK within a year if trial results are positive

When mice were given the pill daily for four weeks, it dramatically reduced sperm counts and was 99 per cent effective in preventing pregnancies, with no noticeable side-effects, according to results published in the journal Communications Medicine earlier this year.

And just four to six weeks after the drug was stopped, the male mice were able to father offspring again. It’s now in the early stages of human testing.

Yet another option could be an ‘after-dinner’ daily pill, called dimethandrolone undecanoate.

Taken after the main meal of the day (as food significantly increases the amount absorbed into the bloodstream), the drug works by suppressing follicle-stimulating hormone and luteinising hormone, both important for sperm production.

And since it doesn’t directly target testosterone, it’s hoped the drug will be free from side-effects.

But why has it taken so long for science to properly tackle the issue of male contraception?

Richard Anderson, a professor of clinical reproductive science at the University of Edinburgh, says the success of the female pill – as well as the various other forms of female contraception – means there has been little commercial interest from drug companies in developing a male version.

Then there’s the often-cited public perception that men – who don’t bear the same consequences of an unwanted pregnancy as women do – cannot be trusted to stick to a daily regimen of contraception.

‘But it’s clear from the trials on Nestorone that the perception seems to be a fallacy,’ says Professor Anderson. ‘Talking to couples who took part, we found most men were very compliant and many of the women were very disappointed when the year-long trial came to an end – as they’d been able to have some time off from carrying all the responsibility for birth control.’