The Male Contraception Information Project is a nonprofit organization that raises public awareness of nonhormonal male contraceptives and advocates for increased government research in the area. The information that follows can be found, in greater detail and with full citations, on their website.
RISUG (Reversible Inhibition of Sperm Under Guidance) is a reversible, nonhormonal contraceptive that provides 10 or more years of protection after a 10-15 minute procedure. A gel injected into the vas deferens which is the tube sperm travel through before ejaculation. The gel then disables the sperm as they swim by. Another injection will dissolve the gel and return fertility. Concerns about side effects and insufficiency of safety data caused a halt to enrollment of human subjects in 2002. These issues were addressed and in 2006 research began again in India
IVD (Intra Vas Device) is a set of tiny plugs that block sperm as they travel through the vas deferens. There are two plugs per side, and the design ensures that any sperm that gets past the first plug will be blocked by the second. Initial research with human subjects found that the method achieved either complete blockage of sperm, made sperm that passed through immotile, or lowered the sperm count enough to make the men essentially non-fertile. Possible negative impact of actually blocking sperm (for example epididymal ruptures) remain, and will have to be address in future research. In 2006 the FDA approved an 18 month trial with 90 men.
Injectable plugs are silicone or polyurethane injections that are injected into the vas deferens and create a barrier to sperm. Research in the late 1980s in Taiwan showed great promise, but later research in China found very different results, with limited effectiveness and problematic side effects. It seems that the size of the vas deferens needs to be considered when injecting the plugs. This method of male birth control seems unlikely to become commercially available or viable in the near future.
IVD RevisitedThere is research in China on a similar plug to the above described IVD (which is unfortunately also referred to as the IVD) which is a mesh-like plug that allows some sperm to pass through it, but only levels that will not result in contraception. The idea is to address concerns about a build up of sperm created by the blockage.
Heat methods of contraception have been known about and used since ancient times. The reasons are not well understood, but the fact that the testes need to be several degrees cooler than normal body temperature in order to produce and maintain healthy sperm is well documented. Given this fact, several researchers over the years have hypothesized and developed methods to produced infertility by heating up the testes for periods of time. These methods include everything from simply soaking in hot water, to wearing specially designed underwear (contrary to the popular myth regular mens briefs do not cause infertility by overheating the testes), as well as a technique to keep the testes elevated and closer to the body.
Ultrasound seems to be a simple and convenient form of contraception that unfortunately has received very little research attention. Ten minutes of ultrasound can result in six months of birth control. The Male Contraception Information Project offers this description:
For ultrasound contraception, ultrasound waves (very short, inaudible sound waves) are used to heat the testes. The ultrasound waves are of the same type and intensity as those used by physical therapists to treat injuries. To use the method, a man first sits in a special chair with his scrotum in a cup of water. In the bottom of the cup is an ultrasound element, which heats the water about as hot as a hot tub. It has also been hypothesized that the ultrasound creates an ion exchange between the fluid in the seminiferous tubules and the rete testis, making the environment in the testes inhospitable for sperm formation. The method is painless. Some men even report the procedure to be pleasurable. With two treatments 48 hours apart, ten or more months of infertility will result. Fertility returns gradually once the infertile months are over.
What is unknown with this method is whether fertility would return after multiple years of using ultrasound.
In addition to the above, there are several non-hormonal methods of oral male contraceptives that are being researched. More information can be found on the Male Contraception Information Project website.