The decades-long dream of creating a male equivalent of ‘the pill’ is moving closer to reality.
Scientists in the US have begun testing a hormone-free contraceptive tablet in men called YCT-529.
It works by blocking access to vitamin A in the testes, preventing sperm production but without affecting testosterone levels – meaning libido levels are not impacted.
YCT-529 has already been tested in mice and was found to block 99 per cent of pregnancies – putting it on a par with the female birth control medication.
The pill, which experts hope will be available this decade, is the only hormone-free birth control pill for men and the only male pill that researchers are testing in humans.
‘A safe and effective male pill will provide more options to couples for birth control,’ said Gunda Georg, chemist and pharmacist at the University of Minnesota.
‘It will allow a more equitable sharing of responsibility for family planning and provide reproductive autonomy for men.’
For men, only two contraceptives are available to prevent pregnancy in their partners – condoms and vasectomies, also known as ‘the snip’.
A group of 16 volunteers at a clinic in Nottingham are involved in the trial of the drug, called YCT-529, to see if it can stop the formation of sperm (stock image)
YCT-529 causes infertility in mice after four weeks of oral administration and is fully reversible within six weeks after dosing ended. Pictured, male mice testes under the microscope
Around a quarter of women who use contraception use an oral birth control pill, but there are no equivalent methods currently available for men.
YCT-529 is being worked on as part of a collaboration between University of Minnesota College of Pharmacy, Columbia University in New York and San Francisco-based firm YourChoice Therapeutics.
Results of the testing phase in mice and cynomolgus monkeys have been published in Communications Medicine.
In the team’s lab experiments, the drug caused infertility in male mice and was 99 per cent effective in preventing pregnancies within four weeks of use.
Meanwhile, in the male non-human primates, the drug lowered sperm counts within just two weeks of starting the drug.
Crucially, both mice and non-human primates fully regained fertility after stopping the drug and no side effects were detected in either species.
Mice regained fertility within six weeks, while non-human primates fully recovered their sperm count in 10 to 15 weeks.
Already, the first human trials of the drug (phase 1) have been completed, which showed ‘the drug candidate was safe for use in men’.
Graphs demonstrate decrease and recovery of sperm counts and unchanged hormone levels in cynomolgus monkeys
A male contraceptive pill has been 70 years in the making. Today, men have condoms or withdrawal as the only two practicable birth control options (file photo)
Safety and efficacy testing in a small number of male volunteers (phase 2) started in New Zealand and is ‘progressing well’.
With phase 2, the team anticipate another efficient trial and hope to announce results later in 2025.
Scientists have been trying since the 1950s to develop an effective male contraceptive, including pills, gels and injections, but none have been approved.
The last serious innovation in male birth control was back in 1839, when American chemist Charles Goodyear discovered vulcanised rubber which brought condoms to the masses.
For men today, the only two reversible birth control options are still condoms or withdrawal – scientifically known as ‘coitus interruptus’.
A vasectomy blocks or cuts part of the male reproductive system called the vas deferens, which keeps sperm out of the semen.
A vasectomy can be reversed by way of a costly procedure, but there can be painful side effects and it doesn’t always work.
The non-hormonal drug called YCT529 works by inhibiting a protein important for the normal development of sperm. Pictured, existing oral contraceptive pills (file photo)
The chances of success for a vasectomy reversal depend on how long it’s been since your original vasectomy procedure.
Meanwhile, condoms – which have been made with latex since the 1920s – have high failure rates due to issues like slippage and manufacturing defects.
‘I can’t think of another area of medicine where innovation has stalled for nearly two centuries,’ said Akash Bakshi, CEO at YourChoice Therapeutics.
‘We need more male methods, and we need them quickly.’
If commercialized, YCT-529 would give men an oral contraceptive akin to the female option that was approved for release in the 1960s.
In comparison, women have several birth control options available including short-term rapid methods like birth control pills and patches and a contraceptive cap or diaphragm.
They also have long-term options such as implants (which produce hormones that stop the release of an egg) or an intrauterine device (a T-shaped device placed into the uterus to prevent an egg from implanting).
The birth control pill or patches is about 93 per cent effective at preventing pregnancies while long-term devices like the intrauterine device are more than 99 per cent effective.
