Our top picks for emerging methods
Which male contraceptives could be ready first? Which ones are the most promising? Here are our top picks:
- What it is: A polymer gel that goes in the vas deferens and blocks sperm. It is expected to be reversible, based on preclinical studies in rabbits.
- Why we like it: It’s ultra-targeted and specific—no hormone side effects throughout the body. Like vasectomy, it’s “get it and forget it”—one 10-minute procedure and then nothing to think about after that. But unlike vasectomy, it looks like it will be reversible—a huge difference, since psychologically, most people like to keep their options open, and men who aren’t finished having children could use it too.
- The holdup and next steps: Vasalgel is being developed in the U.S. by a nonprofit foundation — now all that’s needed is additional funders and investors for the $6 million social venture project. A related compound, RISUG, is in advanced clinical trials in India and could be available on a limited basis there in the future.
- What it is: A quick-acting, nonhormonal male pill that acts by temporarily shutting off the muscles that propel sperm and semen. It’s based on an old blood pressure medication that has too many side effects to use, but researchers are picking out the parts of the drug that affect semen and not blood pressure.
- Why we like it: By eliminating semen, it could potentially drastically reduce the transmission of HIV. And as a quick-acting method, it would be a good complement to Vasalgel or RISUG as part of the “contraceptive supermarket.”
- The hold up/next steps: Researchers need $300,000 for lead optimization (testing the parts of the drug they’ve identified as most powerful at stopping semen, without the other effects). Then thorough testing would be needed to make sure the side effects of the old parent drug are really gone. But contraceptive funders aren’t excited; it’s just another early-stage male contraceptive lead to them, and they think men wouldn’t accept having a semen-free orgasm even if it feels the same. HIV/AIDS funders, who have a lot more money, mostly aren’t aware of the research. What’s needed? $300,000, or activism to petition contraceptive and HIV funders to make it a priority.
- What it is: Fifteen minutes of painless treatment to the testes provides six months of contraception.
- Why we like it: It’s targeted (testes-only), so there are no unpredictable side effects like with hormones. And it’s done using machines that are already in physical therapists’ offices all over the world. Multiple treatments one after another a few days apart can even be used for permanent sterilization. Researchers at the University of North Carolina have confirmed the original researcher’s results, getting an effect in rats—but it took a lot of adjusting to get it right. Armed with those results, they were able to win a small Gates Foundation grant to study it further. Researchers in Italy are successfully using ultrasound to sterilize male dogs, and researchers at the University of California have gotten it working in monkeys (but for about 6 weeks, not 6 months).
The catch/next steps:How is sperm quality as fertility is returning? Will fertility always bounce back, even after multiple uses of the method? It now seems more promising as a permanent method (a nonsurgical alternative to vasectomy), rather than a 6-month method as originally imagined, and should probably be tested that way.
- What they are: Extracts from plants traditionally known to have contraceptive effect. The most advanced work is on plants from India, China, and Indonesia.
- Why we like it: This would satisfy people who want a short-term method—and we already know it works.
- The catch: To make enough to satisfy the world’s men, you can’t just gather plants—you have to identify the active compound and then chemically synthesize it, which requires very specific skills. Researchers on the Indonesian pill (Justicia gendarussa) have already done this, but researchers on the Indian and Chinese compounds (carica papaya and TW) haven’t. Then you need to test it extensively, since plant compounds can have effects throughout the body (for example, the Indonesian plant seems to have effects similar to aspirin, and the Chinese compound, Tripterygium wilfordii, is used in higher doses to treat autoimmune disease). Finally, reversibility studies need to go on long term before an oral drug can be considered reversible rather than just a vasectomy alternative. This will require a concerted, coordinated effort, preferably at a center funded specifically to test and compare compounds. And that means money!
- What they are: The testes need to be slightly cooler than the rest of the body to properly produce sperm. If you keep them at body temperature during the day (with an underwear modification to keep them tucked in the inguinal canal), or a lot warmer for a shorter period of time (with testes-only baths for 45 minutes a day for 3 weeks every 6 months), contraception can be available for free.
- Why we like it: It’s simple, free, and available right now to anybody.
- The catch/next steps: It takes dedication. And though there are lots of small studies that show it works, the low-tech nature and “eww, weird” factor has kept funders from supporting the large studies that would be reassuring.
Note 2016: Link broken? Doing historical research? Try the previous (2011) archived version of our site if you need a particular link or reference.