Vasalgel, Non-Hormonal Male Birth Control, Tested Successfully In Monkeys & Here's Why That's Huge

Parsemus Foundation

There’s new news regarding male birth control. Vasalgel, the future male contraceptive, tested successfully in monkeys, the Parsemus Foundation, the company behind developing Vasalgel, tells Bustle. The results were also published Monday in Basic and Clinical Andrology. The new contraceptive method worked in rhesus macaque monkeys for more than one year — which is ~huge~ news. Plus, Vasalgel produced fewer side effects than a vasectomy, the study found.

All 16 monkeys in the Vasalgel study were part of the resident colony at the California National Primate Research Center. They were monitored for at least one breeding season, and seven of the 16 were almost continually housed with females for two years. The authors of the study reported that there were no conceptions after the Vasalgel injections. W-o-w!

“The study provided several important factors critical to eventual use of the product in humans,” Linda Brent, PhD, MBA, Executive Director, Parsemus Foundation, tells Bustle. “The procedure was highly effective. None of the males who were given Vasalgel impregnated any females (even though they were all in groups with up to nine adult females!). Measuring success of a contraceptive in terms of pregnancy rate (rather than simply the presence or absence of sperm) gives us ‘real- world’ information, which is most relevant to the human condition.”

"This is really important information as we prepare for human clinical trials."

And vasectomies are actually more complicated for monkeys in general, so the fact that Vasalgel worked in the monkeys is great news. “While vasectomy is a quick and relatively simple procedure in humans, in monkeys there can be additional complications, as it is inherently more complex,” Angela Colagross-Schouten, lead veterinarian on the project, in the press release announcing the latest Vasalgel study. “We were impressed that this alternative worked in every single monkey, even though this was our first time trying it. Vasectomies are a routine procedure for nonhuman primate veterinarians, so to have similar or even slightly better outcomes trying a brand new procedure is very encouraging.”

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How Does Vasalgel Even Work?

ICYMI, you may be wondering how Vasalgel works. It’s similar to a vasectomy in that sperm can’t leave the vas deferens. However, unlike a vasectomy, Vasalgel just involves inserting a polymer hydrogel into the vas deferens — not having surgery. So, sperm cannot get through to an egg. Seminal fluids are still released, but not sperm, since they’re too big to get through the gel. Instead, they’ll be reabsorbed into the body. Science is ~amazing~.

Plus, Vasalgel is long-acting, non-hormonal, and potentially reversible. “The contraceptive effect of Vasalgel has been ‘reversed’ in a rabbit model by flushing the material out with a simple sodium bicarbonate solution,” stated the press release announcing the new study. “Sperm flow quickly resumed.”

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What About Vasalgel And Human Males?

Vasalgel is being developed by Revolution Contraceptives LLC, a social venture subsidiary of the nonprofit Parsemus Foundation. You may remember Vasalgel in the news last Spring, when it was announced that Vasalgel testing would soon happen in human males after the gel tested successfully in rabbits and baboons. And now, rhesus monkeys have been added to that list. “The purpose of the current study was to put Vasalgel to the ultimate test — preventing pregnancy, not just eliminating sperm — in larger animals more anatomically similar to humans, before human use,” the press released stated. “However, the contraceptive had benefits to the monkeys as well.”

Brent also says the Vasalgel injection was well-tolerated by the monkeys, and that they're covered quickly. Plus, they were put back in their social groups right away.

"Vasalgel has the potential to revolutionize birth control."

“They even had fewer complications than a comparison group of monkeys who received vasectomies,” Brent says. “This is really important information as we prepare for human clinical trials. The outcome of the study helps to support the safety of Vasalgel. A one-time injection was not only important for monkeys (whom it would be difficult to give repeated injections or daily pills to, like other contraceptives), but is important for humans, as well. We already know from long-acting female contraceptives, like implants and IUDs, that a single administration is much more effective and not subject to accidentally forgetting a pill. A final important outcome for both monkeys and humans is that this form of birth control is non-hormonal. No impact on normal hormones and behavior, and no side effects that can occur with hormonal methods.”

Impressive. Just the idea of semi-long-term male birth control is mind-blowing, too, aside from the fact that it’s been working in animals. And human males could be next.

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“Vasalgel has the potential to revolutionize birth control,” Elaine Lissner, founder and executive director of the Parsemus Foundation, tells Bustle. “Women have multiple options (each with its own drawbacks), but right now there’s nothing out there both reversible and highly reliable for men,” Lissner says. “Clearly, we need an effective, long-acting, reversible option for men. Many men are excited about Vasalgel because it could be that option.”

I definitely hear that! You, too?

When Will Human Males Be Able To Use Vasalgel?

Preparations are being made for the first clinical trial in humans, says the Parsemus Foundation. The first study will explore effectiveness and later studies will attempt reversal — flushing the gel to restore sperm flow. Assuming all goes well and Vasalgel is released, the Parsemus Foundation hopes for a tiered international pricing structure, to make sure all men can afford it.

Wow, huh? The fact that human males may be able to have their own form of birth control is ah-mazing, and I’m curious to see what happens next. As Lissner said, it’ll revolutionize birth control, that’s for sure.