A Pill a Day Keeps the Sperm Away
A European pharmaceutical company called Organon plans to market the product when it's ready, which will be a minimum of five years, says Anderson. Organon provides the products for the trials, but otherwise, he says, the studies are funded by research grants.
This type of hormonal research, which follows in the footsteps of previous research leading to the female pill, has been going on for years, says DePaolo, and is the most heavily researched form of male contraceptive. But it's not all.
There's been a lot of effort invested into injected vaccines that are antibodies to specific proteins involved in fertilization. These antibodies, whether in the sperm or on the egg's surface, attempt to prevent the sperm from binding to it, says DePaolo, adding that there have been some promising leads that seem both effective and reversible, "but it's not something that's easily controlled."
Outside of condoms or vasectomies, there have also been many other contraceptive possibilities tested, some to no avail; some are still being researched. Testosterone alone was shown to reduce sperm production in most men, but depending upon the type and amount, there could be serious side effects, ranging from the lowering of "good" cholesterol, an increase in weight and decrease in the size of the testicles, to acne, mood changes, or less than complete effectiveness.
The estrogen derivatives, such as the hormonal steroid used in the Scottish trial, were added to try to get around some of these side effects. They may have gone under different names, with slightly different effects, but the goal was the same. They've all been used in conjunction with testosterone that's been injected or given in a patch or implant.
Other contraceptive possibilities, some of which are promising:
- A non-hormonal pill that prevents the release of sperm into the semen. So far, experiments with genetically altered mice have had some success.
- Non-hormonal compounds that prevent the development and maturation of sperm cells. So far, only animal tests have been completed. However, there are reports that the compounds can cause up to a 40% to 50% reduction in testicular size.
- Plant extracts like gossypol and Tripterygium wilfordii. Gossypol was used in daily doses in Chinese men, but Tripterygium has primarily been studied in animals. They inhibit sperm production, but the effects may be irreversible, and gossypol was found to shrink the testicles.
- Nifedipine, a calcium channel blocker used for high blood pressure, appears to cripple sperm -- making them unable to fertilize the egg.
Mifepristone, known as RU-486, the abortion-inducing drug, has been shown to stop sperm from moving normally and fertilizing eggs. But it has hormonal side effects that make it useful as a tool for further research only.
- A silicone plug injected into the vas deferens, to stop the sperm from entering the semen. Supposedly, it's reversible in the hands of a "skilled" surgeon. Hundreds of thousands of Chinese men have undergone the procedure.