Thermal Male Contraception is the new hot thing.
It’s Men’s Health Week at Playboy and we’re exploring the increasingly DIY state of men’s healthcare. From the peptides ruling Hollywood to the Reddit forums replacing doctors, men are taking their health into their own hands. Here’s what you need to know.
“Thermal is amazing,” a poster on Reddit declares. “All I can say is wow.” Commenters respond enthusiastically, congratulating them on discovering the method and asking what they meant when they wrote they were “experiencing typical changes” when using it. In this case, the OP is not talking about slipping on a cozy pair of long johns or discovering a remote hot spring. They are one of a growing number of people who are convinced thermal male contraception—that is, heating your testicles to a point where you are no longer fertile—is the future of reproductive health care.
Many studies have found that prolonged exposure to heat can have an impact on sperm count and viability because the higher temperatures lead to DNA damage. In other words, heating up your balls can make you temporarily (probably) infertile. Hence, the rise of thermal male contraception.
Using thermal male contraception (TMC) can look like a lot of things, though all the methods feel quite DIY right now. Some men will dunk their testicles in “just bearable hot water,” as Florian Breu, a 46-year-old proponent of TMC, describes it. There are some electronic devices, similar to heating pads. There are rings available for purchase that slip over the penis and testicles to hold the latter close to the body, increasing their internal temperature. You can also make a similar ring or jockstrap yourself, as Michel, 32, has done.
Michel lives in France, considered to be the country leading the way in TMC research and adoption, and has found community there among other fans of the method. He recalls “sewing DIY jockstraps with men around a table in a bar,” bonding over beers and each other’s stories of the awkward experience that is getting your sperm levels tested to ensure those DIY jockstraps are actually working. These types of gatherings “always spark very interesting and enlightening conversations,” Michel says. “It also pushes us men to be more open and vulnerable about our intimacy in a cool way.”
When it comes to birth control for men, the options are largely limited to condoms and vasectomies—both of which are safe and effective. But in recent years, there’s been growing demand for a medication or device that is more in line with the pills and implantable devices women can use. However, there’s a bleak joke among those in the male contraceptive space that we’ve been 10 years away from a new male birth control method for 50 years. “The joke is so old now that the number is actually 70 years,” says Logan Nickels, PhD, chief research officer at the Male Contraceptive Initiative (MCI).
There are many reasons that research into male birth control has been slow. Some of this has to do with the complications around testing: Any medical device or procedure that potentially involves pregnancy comes with increased ethical considerations, but it’s especially complicated when the person using the method isn’t the patient who could end up pregnant if it doesn’t work, so the risk-benefit is a less clear. The risks for taking contraception as a woman—like blood clots and mood swings—are greatly outweighed by the risk of getting pregnant, Nickels says. “Pregnancy is more of a health risk [than those potential side effects] so therefore it is ethical to administer contraceptives to women because we mitigate the health risk of pregnancy,” he explains. “Men don’t get pregnant. There is no health risk for men in pregnancy.” Sure, you could argue that the man is mitigating the health risk for their partner, but that’s not something we currently have a regulatory framework for.
For thermal specifically, funding has been an issue. A vat of hot water or small plastic ring isn’t exactly going to be a lucrative venture for a pharmaceutical company, which would likely need to invest millions of dollars into research and development. In the experience of Félix Minvielle, head of clinical development at Entrelac, a France-based organization that advocates for and supports research into male contraceptive methods, pharmaceutical companies and governmental agencies aren’t interested in funding the types of projects Entrelac wants to support. “They tell us, ‘Oh, that’s really great what you’re doing. Sadly, we don’t have money for you.’”
Then, there are the societal reasons why male birth control hasn’t been a priority for researchers: Preventing pregnancy has generally not been considered the responsibility of the person with testicles. “When we think about pregnancy, we think of it as a woman’s problem,” says Arthur Burnett, MD, a urologist at Johns Hopkins. He believes that has historically carried over into the scientific community as well. As Minvielle puts it: “The overarching hurdle to all of this can be summed up as ‘the patriarchy.’”
But attitudes are changing. “We’ve emerged into this new sexual revolution,” Dr. Burnett says. Heather Bartos, MD, an ob-gyn based in Texas, agrees. “I think younger men especially are more engaged in conversations about reproductive responsibility than previous generations,” she says. Nickels says members of the general public will tell him, “I’ve been following [male contraception research] for 10 years and it’s going nowhere. I’ve got to do something.” The reasoning can be summed up quite simply: “Men want autonomy,” says Christoffer, an engineer and TMC activist living in Frankfurt, Germany. “Women don’t want the whole burden of contraception.”
So it makes sense that people with testicles would be trying to take things into their own hands, especially as women’s access to reproductive health care is threatened in the United States. And as wild as dunking your balls in a vat of hot water might sound, the thermal method actually probably works pretty well, as long as you’re diligent about daily prolonged exposure to heat.
“Thermal contraception is not made up,” Dr. Bartos says, pointing to research that shows fevers and hot tubs can affect sperm counts. Dr. Burnett agrees, noting that it’s maybe one of the oldest effective methods of birth control. “A medical professional might say that this is a primitive kind of intervention that goes back to times when we just didn’t understand the science of spermatogenesis,” he says. The goal now should be to “target these things in a more scientific way.”
Everyone interviewed for this piece—plus the enthusiasts posting on Reddit—emphasize that this is very much an experimental method that needs a lot more research before doctors would ever recommend it as a reliable contraceptive method. This seems to be less about whether or not it works—again, even putting a laptop on your lap for too long can lower sperm count—and more about whether it’s easily reversible if the guy decides he wants to be fertile again.
“You can do almost anything in an extreme way to make yourself infertile. You can even cut your testicles off,” Dr. Burnett says. “If somebody’s very extreme [in using TMC], I’m sure they can achieve good success. The question is, if he decides he wants to be fertile again … will this be reversible? We need better evaluation to the extent that that’s successfully achieved.”
There’s also a concern about a potential increased cancer risk, due to an established correlation between men who have undescended testes and higher rates of testicular cancer. However, scientists aren’t 100% sure why this correlation exists. “Is that due to the heat and long-term exposure of the testes? Would that be relieved if you only wear [a TMC device] for 16 hours a day? Or are [undescended testes] associated with underlying conditions? We don’t know any of this,” Nickels says.
As far as any physical side effects go, you can practically hear proponents rolling their eyes when men ask if these TMC rings hurt. When a guy cringes at the idea, “we ask them what they know about putting an IUD inside a body or what hormones can do to a woman,” Minvielle says. “They’ve just never thought about having their body engage in some form of constraint to contribute to contraception.”
However, in a stunning win for weaponized incompetence, most people do seem to understand why a woman might be hesitant to let a male partner handle contraception. “Relying on men to get the job done is a little scary for women,” Dr. Bartos says, especially as options to terminate an unwanted pregnancy become more limited in the U.S. “I totally agree with that,” Minvielle says. “If I were a girl myself, I would see tons of reasons not to trust men on contraception.” As Christoffer puts it, “A lot of men aren’t stepping up today.”
The men who do use TMC as a way to “step up” anecdotally report great results. Beau says he started experimenting with thermal because his partner can’t use hormonal birth control. “In January 2023, I tried to build a device,” he says. “I ended up with a chair that had a fitted water cup with heating and some ultrasound head below.” He used the chair with “just bearable hot water” every day for 30-45 minutes, but ultimately wasn’t satisfied with the sperm count this method resulted in.
When he started using the ring method—first the Andro-Switch, a TMC ring that’s officially being sold as a “talisman” while it awaits government approval, then a DIY version his partner sewed—a lab test showed that his sperm count was at a level considered too low for successful conception. It was that test that totally sold his partner. “After seeing the lab sperm analysis sheet which did state 0% vital sperm she was convinced and we skipped condoms,” Breu says. So far, they haven’t had any pregnancies.
Thermal contraception is “a little fringe, even in male contraception, which is niche and fringe,” Nickels says. “But I think they have their finger on a pulse that nobody else does.” Again, no expert is recommending this as a reliable birth control (yet), “but it really heartens my spirit to say that there are people out there that are willing to take their health into their own hands,” he says.
Whether it’s thermal or another male contraceptive method that becomes widely regarded as safe first, Minvielle thinks this conversation is bigger than birth control. “Personally, my research question when I started this project was how to onboard men into feminism,” he says. “I think that contraception is an interesting Trojan horse because it talks about intimacy, the relationship to the body, to the people we say we love, to the sense of responsibility to oneself.”
“This is not a new way to create value for guys,” he adds. “It’s just something that we want people to think is normal.”
For Michel, TMC has become both normal and something he sees all sorts of benefits from using beyond preventing pregnancy. “It gives us more autonomy to do what we want with our fertility,” he says. “Thinking about this topic also encourages us to challenge our views on related topics like sexuality, consent, communication, and gender. I think it honestly helped me be a better person.”