Couples are being recruited to take part in a groundbreaking trial of a male contraceptive gel that could allow men and women to take equal responsibility for birth control in the future.
Eighty men in Manchester and Edinburgh will be asked to use a daily gel containing hormones that "send the testes to sleep", meaning the sperm count drops to zero.
Couples will rely on the gel as their sole contraceptive for a year, as part of a clinical trial to assess how effective it is at preventing pregnancy and whether the side effects are acceptable.
Richard Anderson, a professor of clinical reproductive science at the University of Edinburgh, who is leading the study, said the method was expected to be more effective than condoms, which in real life are about 82% effective. "We're aiming to get it down to the kind of level you get with the pill which is a very small but no zero failure rate," he said.
The gel, called NES / T, is a hormone-based treatment designed to reduce sperm production without affecting libido and works in a very similar way to the female pill. It contains progestogen, which acts on the brain's pituitary gland to switch off sperm production. The gel also contains testosterone to offset a drop in the male hormone caused by progestogen, which could otherwise cause unpleasant side effects.
One of the reasons the quest for a male pill has proved so hard because the hormones are quickly metabolized by the liver. A gel gets around this because it is absorbed from the skin directly into the bloodstream.
Men will be given the gel in a small pot, which includes a pump to administer a specified dose. The gel is rubbed into the shoulders and upper arms daily and the men will attend monthly clinics to monitor their sperm count.
Once a man's sperm count has dropped to almost zero, which is expected to take a few months, couples will use the gel as their sole contraceptive and be followed for more than a year.
According to the scientists, there is considerable demand for new forms of contraception. "I do not think it's going to replace the key female methods but there certainly is a demand for an alternative," he said. "A lot of women do not want to go on the pill, some have migraines or put on weight. Couples quickly run through the options. "
Previously, Anderson's team led the trial of a male contraceptive injection, based on a similar hormonal approach, which was found to be almost as effective as the female pill. The trial was stopped early by the World Health Organization because of its side effects, which included acne and increased libido. But Anderson said very few men dropped out of the trial and three-quarters said they would opt to continue using the jabs if given the option.
Any hormonal contraceptive method is likely to have some side effects, as seen with female contraceptives, he said. "This is the real world of contraception."
If the trial is successful, there is likely to be an interest in developing the gel as a commercial product, according to the researchers. While contraceptive gels are not available, testosterone gel is already widely used in the US as a male hormone replacement product.
Men between 18 and 50 are invited to participate in the trial by calling 0161 276 3296 (Manchester) or 0131 242 2669 (Edinburgh). "Anyone who's interested, we'll be happy to hear from them straight away," said Anderson.