RISUG: Birth Control for Men

According to an enthusiastic article on the Internet, “The Best Birth Control In the World Is For Men.”

It’s called RISUG: Reversible Inhibition of Sperm Under Guidance. It involves a minor surgical procedure in which the vas deferens is exposed and pulled outside the scrotum by the same techniques used for a vasectomy. A copolymer, powdered styrene maleic anhydride (SMA, for which the method was previously named) combined with dimethyl sulfoxide (DMSO) is then injected into the vas deferens. The polymer coats the walls of the vas and kills the sperm as they swim by. The mechanism is not understood, but the developer thinks the polymer’s mosaic of positive and negative charges causes the membranes of the sperm to burst, rendering them immotile.

RISUG is rapidly effective: in a phase II clinical trial in India, viable sperm were absent as soon as 5 days after the procedure. They say there have been no pregnancies in the first months “other than a handful of cases in which the RISUG was not injected properly.” (One wonders how they determined that it was not injected properly: by the fact that pregnancy occurred? Could this be just a rationale to explain away failures? Or to spare patients the embarrassment of discovering the wife had another sperm donor?) The contraceptive effect is said to last for a decade or more; it might require repeat injections every 10 years.

In contrast to vasectomy, RISUG can be reversed by injecting DMSO or bicarbonate and using a combination of vibration, a low electric current, and rectal massage to dislodge the polymer and move it through the vas deferens.

It is not yet approved in India, but it has already been patented in several countries. Efforts are underway to seek FDA approval in the US under the name Vasalgel, but don’t look for it on the market anytime soon: preliminary studies on rabbits are just getting started. 

It sounds crazy, but there is evidence to support it. A search for RISUG on PubMed brings up 18 articles. Some are lab studies, some are not directly relevant, and some are reviews of contraceptive methods; but there are a couple of very encouraging studies in monkeys and a report of a phase II human trial with 12 subjects. 

An article in Wired calls it the revolutionary new birth control method for men and includes a video so you can watch the actual procedure. It says:

It’s the brainchild of a maverick Indian scientist named Sujoy Guha, who has spent more than 30 years refining the idea while battling bureaucrats in his own country and skeptics worldwide. He has prevailed because, in study after study, RISUG has been proven to work 100 percent of the time. Among the hundreds of men who have been successfully injected with the compound so far in clinical trials, there has not been a single failure or serious adverse reaction. The procedure is now in late Phase III clinical trials in India, which means approval in that country could come in as little as two years.

There are some worrisome red flags here: lone genius, battling the establishment, reference to “study after study” when Phase III trial results are still pending, and the claim that it is 100 percent effective. No contraceptive measure is 100 percent effective, not even hysterectomy: abdominal pregnancy can occur even after a total abdominal hysterectomy.


RISUG may be a promising means of birth control for males, but it’s too early to draw any conclusions. The current media hype is unwarranted. Science will have to run its course and complete well-designed clinical trials before the method can be recommended.

Posted in: Surgical Procedures

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14 thoughts on “RISUG: Birth Control for Men

  1. gretemike says:

    Does “minor surgical procedure” ever belong in the same sentence as “scrotum”?!

  2. fledarmus1 says:

    I’m not exactly sure how “it is 100 percent effective” squares with “no pregnancies in the first months other than a handful of cases…”

  3. nobeardpete says:

    @fledarmus1 – It’s 100% effective _except for_ those few cases.

  4. Epinephrine says:

    Does “minor surgical procedure” ever belong in the same sentence as “scrotum”?!

    Definitely. Having had a vasectomy, it is pretty darn minor surgery. I get that it was meant as humour, but there are enough men too squeamish or worried about these procedures (with their partner sometimes deciding to undergo a much more serious surgery as a result) that it’s worth combating that perspective.

    If it’s really effective, safe, and easily reversed, it would certainly be welcome (not for me, I’m done, but I am sure that there are some who are less certain than I was).

  5. cervantes says:

    “100% effective, except for those few cases.”

    Just like it says on the V8 bottle: “100% vegetable juice. With added ingredients.”

  6. annappaa says:

    Weirdly, I’ve written about RISUG before (perhaps too enthusiastically?), and have also written a bit about the history of hormonal birth control (and am working on a longer synopsis of this history to be debuted this summer).

    There were similar “lone genius” and “battling the establishment” themes in the history of hormonal birth control as well. My favorite “lone genius” in the birth control story was Russell Marker, the chemist who figured out how to synthesize progesterone from a wild Mexican yam. He apparently didn’t have a lot of institutional support and financed most of his early research with his own savings.

    As for “battling the establishment” — Margaret Sanger dreamed of a “magic pill” since at least 1912, when she wrote about her vision, but despite the fact that the technology was coming together, there was no government or corporate interest in developing hormonal contraception. Sanger got a wealthy friend to bankroll pretty much the entire initial research, but once the inertia was overcome the pharmaceutical companies got on board.

    At least these narratives were the common ones presented in a multitude of sources I read. And, yes, the “lone genius” did have some help. I think humans just love the “lone genius” narrative. Maybe on some level we all think we are lone geniuses, which makes us root for them.

  7. windriven says:

    The use of DMSO as (presumably) the solvent caught my eye. DMSO has a variety of interesting characteristics. It seems to have the ability to transport relatively large molecules through the skin – it has been sometimes used in transdermal preparations as well as allegedly by Soviet era spies to transport poisons through the skin. It also seems to potentiate the biological activity of some compounds.

    If you wet a cotton ball with DMSO and rub it on the back of your hand, within a few seconds you will taste it (a subtle oyster-like flavor) – it moves through the tissues that easily.

    I would be very, very skeptical regarding the safety of DMSO as a solvent in this application without very careful long term studies.

  8. nord says:

    “100% effective”…

    I wonder if the coating site is close enough to the perineum to be affected by cycling.

  9. relativitydrive says:

    The funny thing is I’ve come up with a better solution and have been working on it for years. By working on it I mean in the homeopathic way – doing nothing more than wishful thinking.

    Take each male child at birth (and later on do all men) and put a couple of electronically controlled taps into the vas deferens set to OFF. When people want children they apply to get it turned to ON for a selected period before it automatically turns back to OFF. Easy as.

    So, I was excited when I saw this option. Then I realised this doesn’t look so good but let’s hope it can be used until Big Pharma fund me with millions of £££s…I can be contacted via this site.

  10. BillyJoe says:

    “RISUG can be reversed by injecting DMSO or bicarbonate and using a combination of vibration, a low electric current, and rectal massage to dislodge the polymer and move it through the vas deferens.”

    My feeling is that most males are going to find excuses to avoid this treatment.

  11. mousethatroared says:


    Heck, I’m a woman and I’d avoid this one (at least for a good long time). When I hear the description, not only do I cringe at the reversal process, but it draws to mind the initial problems with the IUD. I wonder about the device become dislodged and becoming embedded somewhere it shouldn’t, causing failure or infection, negative reactions to the materials, scar tissue, etc.

    I’m not a scientist or medical person, but I’d really want to see evidence of long term safety and effectiveness before jumping on this bandwagon.

  12. @BilllyJoe, avoid it?? I know a lot of guys who’d pay for an electrical current to the prostate!


  13. DavidRLogan says:

    Don’t forget about the continuous use of anabolic steroids!

    Not as fancy as this treatment…but effective, and you get hyooooooge (am I kidding?)

    Thanks for the post, Dr. Hall.

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