What you should know about the ongoing hunt for male birth control

In 2016, it was widely reported that a clinical trial of birth control for men had been halted after the participants reported side effects, including severe mood changes and acne. A clamour arose from the internet: Women who rely on hormonal birth control (for contraception as well as other uses) have been suffering side effects for 60 years and counting, dating back to the clinical trials of the first birth control pill in the 1950s. Why shouldn’t men have to endure some moodiness and zits in order to shoulder a little more of the contraceptive burden?

Scientists have been studying hormonal male birth control for decades — the first U.S. research began in the ’70s — but no option has made it past clinical trials yet. That’s not because men aren’t interested. It’s far more complicated than that on a medical, scientific, and practical level. Before we dive into the most promising options that could be available at some point, it’s important to understand the hold up.

Firstly, balancing the risk of pregnancy with the potential side effects of tinkering with your hormones is very different depending on whether you’re the person who could actually be getting pregnant. Preventing the implantation of an embryo has innumerable benefits for people who can get pregnant — pregnancy can be a life-threatening condition even in healthy people, and comes with a laundry list of related health problems and often-lifelong side effects. These range from dangerous complications in the first weeks of pregnancy to gestational diabetes as well as the physical traumas that pregnancy and childbirth can cause, such as longterm pelvic floor disorders.

That’s the reasoning on a purely physical-health basis — the effects of unplanned or unwanted pregnancy on mental, psychological, financial, and social well-being (not to mention the stress and access issues relating to terminations) are both too obvious and too numerous to list here, and women who choose to bear the side effects of contraception to avoid the risk of pregnancy have done the math.

The physical symptoms of impregnating someone else, however, are precisely zero — the ejaculating party has always had, quite literally, less skin in the game. Giving women the tools and therefore the agency to avoid getting pregnant before giving men the tools to avoid causing pregnancy was the correct order in which to do those things, whichever way you slice it.

It’s also the logical order scientifically and mathematically speaking, because making women less fertile is generally an easier problem to solve. In order to prevent pregnancy, you need to get in the way of one egg that’s released once every few weeks — or get in the way of the 40 million to 1.2 billion sperm cells released in a single ejaculation.

Condoms are the main way men have been able to take responsibility for avoiding pregnancy for hundreds, if not thousands, of years, and have the significant benefit of protection from most STIs, but are susceptible to human error — especially in the heat of the moment — and the fact that they function as a physical barrier can be frustrating, especially in monogamous relationships where the risk of STI transmission is minimal and contraception is condoms’ sole benefit.

The only other male-driven method that’s been proven to be effective, apart from withdrawal, is vasectomy. While The Snip is theoretically, and popularly believed to be, reversible, it’s not actually guaranteed to be so in every case, making it less than practical for people who don’t want to get anyone pregnant any time soon but might want to in the future.

The ideal male contraceptive would leave sexual function intact (including the ejaculation of semen that looks and feels “normal”) while disarming those tiny swimmers, using a method that’s 100 percent reversible in a short period of time and doesn’t come saddled with so many side effects that it’s not worth doing.

A number of different methods are being developed to offer men barrier-free sex with women without the risk of pregnancy. Some have been around in various research phases for years or even decades without progressing to market; others have been found to fall short during initial testing, but some researchers still find them worth pursuing.

None of the methods listed below are available to the public yet (except, of course, for participants in the clinical trials). Trials for contraception also take a while to play out — not only do the medications involved need to be confirmed as safe to use in the long-term, they need to be tested over a certain period of time with normal use (e.g. a monogamous straight couple using it as their sole contraception for at least a year) to ensure researchers have enough data to say that they are effective.

(Just a note on language going forward: Statistically, the majority of people with an interest in preventing their sperm from fertilising eggs are cisgender men, meaning their gender identity is the same as the sex they were assigned at birth, who have sex with cisgender women. We haven’t found any records of trans, intersex, or gender non-conforming people being included in the clinical trials we looked at, even though people who are not cisgender or in heterosexual relationships also use contraceptive medicine for a variety of health reasons. We use the terms “women” and “men” as a reflection of the limited research.)

The male birth control gel

When people say it would be good if men could shoulder more of the birth control burden, we didn’t mean it this literally: One of the most promising methods in development is a synthetic testosterone gel that’s rubbed on the shoulders and/or upper arms.

The topical gel contains a hormone called Nestorone, a type of progestin (or synthetic progesterone) that suppresses natural hormone production — the same type that’s used in many contraceptives used by women — and testosterone to replace the suppressed hormones. (Synthetic hormones like progestin work a bit differently than the ones naturally produced by the body, meaning they can serve a slightly different function by continuing certain natural effects, like your sex drive, while not enabling others, like sperm production.)

The gel is dispensed using a pump that provides a standard dose every day. Applying it to the upper body is mainly to prevent it being transferred to others through skin contact in higher-touch areas. Nestorone isn’t effective when taken by mouth in pill form, which is why this hormone cocktail is applied to the skin as a gel. Researchers around the world, from Scotland to California, are conducting clinical trials for the gel and the next round of results are expected in the coming year.

The male birth control shot

A similar combination of hormones as used in the gel has also been tested as an injection. An injectable birth control, usually known as Depo-Provera, is already available for women. A trial for male birth control shots held about a decade ago found that a course of two injections every eight weeks had an efficacy rate of almost 96 percent.

There were some side effects reported, ranging from increased libido, acne, and muscle pain to mood changes significant enough that the researchers eventually stopped enrolling new participants. But, crucially, three-quarters of the 320 men in the study said that they would be willing to continue using the shot despite these side effects.

The male birth control pill

A daily or otherwise regular medication that renders men temporarily infertile, is one version of the Holy Grail of male contraceptives. One promising prospect on the horizon is called DMAU, short for dimethandrolone undecanoate. This compound is significant because it helps keep the active drug in the body long enough that it doesn’t quickly get cleared out by the liver, meaning it could be taken as a once-daily pill.

A 2018 study showed that a daily dose of DMAU reduced testosterone to a level theoretically sufficient to prevent fertility, with some noted side effects including weight gain and, in about 1 in 10 cases, reports of lower libido. This study, however, only looked at hormone levels on paper — it didn’t monitor sperm count, nor did it track the contraceptive effect in sexually active couples. The next step is to confirm, through longer-term trials, that using DMAU daily actually decreases sperm production to a level that can be considered contraceptive. But the research so far has been important as it demonstrates that it’s a safe and tolerable medication to continue testing in clinical trials.

The shot…of gel

This method was first identified as a contraceptive possibility in the 1970s, but it’s still in development now. If it works, it’d be borderline miraculous: a set-and-forget contraceptive, essentially a temporary vasectomy, that doesn’t mess with hormone levels, is dirt cheap to produce and place, and is completely reversible.

The technique is called RISUG, or reversible inhibition of sperm under guidance. It involves the injection of a gel into the vas deferens — the little tube that connects the sperm-production glands to the urethra, which in a traditional vasectomy is snipped. The injected gel renders sperm unviable as it passes through. The gel can theoretically stay in place for up to 13 years, unless it’s dissolved with a simple solution injected in a similar fashion to the gel itself.

The gel is currently in clinical trials in India, consisting of multiple rounds of trials on humans over several decades, as well as in Europe, and is also licensed for development in the U.S. under the name Vasalgel. The most recent American trials in 2017 involved monkeys, and was considered successful after no pregnancies occurred in a social group with all the males injected with the gel.

However, it’s yet to be confirmed exactly how reversible the method is in humans. The Indian team acknowledged in 2019 that while they’re confident reversing the procedure will be as effective as they hope, RISUG could also end up being a solid non-surgical alternative to vasectomy, but with similar or better reversibility prospects.

There’s a significant benefit to this method that isn’t present in others that require regular application or medication. Less scary than a vasectomy, but with the same long-acting efficacy, it could be an affordable option for men and couples in developing countries as well as developed ones. If the reversibility is confirmed, it could be a game-changer.

Do men want male birth control?

Some researchers have argued that overall, the side effects and risks associated with male birth control methods that have been successful in clinical trials are about the same as those faced by women who already use hormonal birth control. This might indicate some bias in the scientific community as to what’s an acceptable rate of adverse effects for men as opposed to women.

Ultimately, contraceptives for men that meet the same standards of usability and accessibility as methods and products currently available for women would be a huge step forward in the fight for reproductive health equity. A 2018 survey found that around 60 percent of straight men would be eager, or at least willing, to try a method they control themselves.

Campaigns to drive awareness, uptake, and proper use would be crucial, but that’s something to worry about once the options are actually available. In the short to medium term, giving everyone more safe and effective options is a net win.