Male contraception: the quest for a pill for men

Male birth control options have been limited to condoms or vasectomy. Since the late 50’s scientists have been working on a male birth control pill. This article reviews the development history of male birth control and what options might be available in the future.

Since the late 1950’s to 1960’s women have had access to the female birth control pill. This innovation in contraception changed the course of family planning worldwide. However, for a variety of reasons, not every woman wants to take hormonal birth control. Despite numerous attempts and partial success under clinical conditions, no comparable product has yet been made available for men. Nonetheless, the drawbacks of female contraception and the limited options available to men (e.g. condoms or vasectomy) leave an unsatisfied demand for a male birth control pill. In this article, we will look at the history of male contraceptive drug development and try to see if there is any hope for a product in the future.

History of the male birth control pill

Pharma companies have long been eager to sell a male pill to the public. Although condoms have existed in one form or another for centuries, the appeal for couples would be a barrier-free method in cases where the woman did not wish to use hormonal birth control. If a hormonal pill could be developed for women, why not one for men as well?

The first serious attempt to develop a male contraceptive drug was in 1957 in a study led by Gregory Pincus, a man who was also involved with developing the first female pill. This and similar drugs were based on regularly administering a chemical similar to testosterone. The presence of excess testosterone in the blood causes a negative feedback loop that shuts down sperm production. Basically, the body detects that the blood contains too much testosterone, and turns off the primary functions of the testicle: sperm and testosterone production. See our article on steroids and fertility for more detail.

Although the direct hormonal approach can be effective in men, it is tricky to make it into a usable pill or injection for several reasons. First, the high required doses of testosterone or similar chemicals tend to cause side-effects such as acne, baldness, and thick blood (high red cells). Second, administering external testosterone can shut down the body’s natural production of testosterone causing the man to suffer withdrawal symptoms. Third, continuous long term use of a chemicals similar to testosterone has been known to cause permanent infertility. In any case, it may take over a year to fully recover a man’s original sperm count after prolonged hormonal suppression. Finally, shutting down sperm production and clearing out the existing sperm from the testicles takes 3 months (incidentally, this wait period also applies for vasectomies). Therefore, unlike the female pill which is effective within weeks, there would be a significant waiting period for the proposed male drugs.

Pharma companies have attempted to balance these risks by careful chemical modifications and dosing. Nonetheless, for one reason or another all clinical trials of male hormonal birth control to date have been suspended before they were complete. In a recent high-profile case, a late stage trial for a candidate injectable hormonal cocktail was discontinued due to unexpected side effects on the mood of certain subjects. Although the effectiveness was comparable to female birth control and it was popular with the subjects (75% were in favor of using the contraceptive), it was decided that the side-effects presented an unacceptable risk for proceeding.

Because side effects on mood are quite common with female hormonal birth control, the reason for discontinuing the study was widely panned in print and social media. Nonetheless, because male contraceptives are new the study sponsors decided that the unexpected nature of the risk required re-evaluating and re-designing the study. It should also be noted that this trial was funded by a consortium of international non-governmental organizations (NGOs) and non-profits rather than a pharmaceutical company.

In short, hormonal treatments *almost* work but they aren’t quite there yet. Research into hormonal birth control for men continues with support from pharmaceutical companies, startups, and non-profits.

Other approaches to male contraception

It has long been known that applied heat can be used as a contraceptive for men by shutting down sperm production. Although this is a potential low cost approach, the lack of an obvious business model has meant that the large studies required to prove the safety and effectiveness of the method have never been conducted. Known methods also take considerable dedication or strange styles of underwear and therefore have not seen significant uptake

One of the primary drawbacks of all methods that shut down sperm production is the long wait time for sperm count to increase or decrease. There are some potential drugs that could disable the sperm cells rather than stopping their production and therefore could become effective more quickly. For instance, the calcium channel blocker nifedipine prevents essential reactions within the sperm cell that are required for fertilization. Other compounds have shown promise in preventing sperm maturation (sperm are no longer motile) or preventing external ejaculation without effecting semen quality. These methods has been shown to be effective and reversible in animals, and it is possible that we will see a quick action male fertility drug sometime in the future.

Finally, there have been advanced trials with various methods that effectively produce a reversible vasectomy by affecting sperm that normally pass through the vas deferens before ejaculation. Perhaps most prominently, RISUG employs an injectable polymer that would disable sperm as they passed through the vas deferens and can be washed out with a second injection. Reversible plugs or gate devices have also been proposed for insertion into the vas deferens and are under development. Although promising, it should be noted that these approaches would have the same waiting period that currently applies to the vasectomy.

Male birth control is coming…

Although significant research has gone into a male contraceptive drug since the 1950s, we don’t have anything ready for the masses yet. That said, there have been a number of methods that *almost* work but have been placed on hold for a variety of reasons. We can’t promise anything, but it wouldn’t be surprising if we see something for men hit the market in the next decade.

Trak Male Fertility Test: Review

I am a health hacker and engineer who is using Trak to keep tabs on my sperm concentration. Here are my thoughts and impressions of the product.

I am a health hacker and engineer who is using Trak to keep tabs on my sperm concentration.  I was particularly interested on the link between lifestyle factors such a heat exposure and fertility.

Perhaps I am not your typical user, but Trak fit a specific need for me. I plan to write a more extensive review of my experience with the product in the future, but for now let’s cover the basics:

The product comes in a good looking sturdy box a little smaller than a shoe box. I don’t normally care about these things, but it was actually pretty useful for keeping all of the materials inside organized for repeat use.

Inside the box is a little machine about the size of a Big Mac with a pair of real alkaline batteries included (rather than the cheapie “heavy duty” kind). There were also 4 individual bags inside, each containing everything you need to run one test. Finally, there were two full color books inside. The instruction manual and a nice, big “Health Guide” with all sorts of information about sperm and health.

Since I intended to use it for sperm tracking, I decided to check out the Android version of the companion App on my Nexus 5. The app ran me through some interesting lifestyle questions (do I cool my balls?!) and gave me a score of 78 out of 100, presumably relating to my sperm health, along with some recommendations for improvement. After poking around, I figured out how to add a Trak result or a professional semen analysis result to see changes over time. I highly recommend that anyone interested in using this product to take a look at the app.

Using the product was fairly intuitive. You “collect”, wait for 30 minutes, add a dropper full to one of the funky looking disposables, attach the disposable to the machine (it presses on like Lego), and close the lid. The machine immediately starts up and spins the disposable for a few minutes. It can be a little startling at first, but it was surprisingly quiet given how FAST that thing was going. When it is done, you read the result by comparing ticks on the disposable to the height of a white column, kind of like an old-school mercury thermometer. The app is helpful with this, because you can mark exactly where your results falls

I’ve been tracking my sperm for more almost a month now. I found that my result varied over time. I started off in the middle of the “moderate” range. After following the feedback from the app, reading the health guide, and making some lifestyle adjustments I was into Trak’s “optimal” range!

Rating: My overall impression of the product was quite positive. It was reassuring to get a result where I could see exactly how far away I was from “low”, and it has been much more convenient to test at home. The price seems a bit high until you consider how much it would have costed to test that many times at the clinic.

Pros:

  • Easy to use and well packaged
  • Clear result that lets you see where you are in the range of low, moderate or optimal for sperm count
  • Mobile App helps with tracking changes in result over time
  • More than a “Cool machine”, it really is a comprehensive approach to improving your fertility
  • Batteries included!

Cons:

  • Collection cups are a bit small
  • Doesn’t measure all the parameters a Semen Analysis from a doctor would
  • Can run through AA batteries quickly

To see for yourself, you can visit TrakFertility.com

Heat based contraception – natural birth control for men?

Can heat be used to lower sperm count? Sperm are much more sensitive to heat than the rest of the body. Prolonged exposure to heat sources such as hot tubs is a well-known cause of reduced sperm count. Repeated and consistent exposure to heat can knock down sperm count so low that it can render a man temporarily infertile.

Testicles hang outside the body for a reason. Optimal sperm production requires temperatures that are a few degrees below body temperature. By dangling free, your balls get natural air conditioning that keeps them just the right temperature to build baby-makers. This is great if you are interested in having children right now, but what if you are more concerned about NOT having children?

As it turns out, exposure to heat can actually be used to reduce sperm count. Sperm are much more sensitive to heat than the rest of the body. Prolonged exposure to heat sources such as hot tubs is a well-known cause of reduced sperm count. Repeated and consistent exposure to heat can knock down sperm count so low that it can render a man temporarily infertile.Can a hot tub be used as contraception? How would men know if they could rely on it? Well, think about it. How you know if you spent enough time heating your balls? How do you check if it worked? What happens if you skip a day or two? Does it work for all men, or just some? I’ll have some answers for you later, but first I’ll try to explain how humanity found out that heat may be used to prevent unplanned fatherhood.

A History of the heat method

It has long been observed that men who work in professions that expose them to heat in the nether regions: bakers, cooks, steamworkers; have had a hard time fathering children. Interestingly, men in these professions were observed to start having children after retiring or finding a new job. Based on these observations, Dr. Martha Vogeli ran a long set of experiments starting in the 1940’s in India. After trying all possible combinations, Dr. Vogeli found a consistent method for inducing temporary infertility in men by a series of hot baths. In short, men who sat in hot water for 45 minutes a day for 3 weeks were protected for at least 6 months.

To achieve 6 months of birth control, the water had to be hotter than the typical hot tub (100-104⁰F). According to Dr. Vogeli, it had to be 116⁰F, similar to a 30 minute old cup of coffee. Lower the temperature to a more comfortable 110F (like a hot shower), and the men were good for at least 4 months.

Dr. Vogeli became a lifelong advocate for the method, and apparently made this a locally popular method of birth control around her test site in India. However, the lack of easily accessible technology to maintain the required temperature, and the inconvenience of sitting in hot water for 45 minutes a day made this method a tough sell. As a woman of the 1940s and 50s, Martha Vogeli also found it difficult to get skeptical men to take her research seriously. The approval of the first female birth control pill in 1957 probably contributed to the lack of popular uptake. Dr. Vogeli’s research was largely forgotten until researchers revisited the link between heat exposure and unexplained male infertility decades later.

A second method for getting the required heat is to get it from the body. This method saw some scientific research in the 1980s and 90s. Remember that sperm production requires temperatures LESS than your core body temperature. Researchers found that underwear that pushed the balls up into the body (aka suspensories) were effective in significantly reducing sperm count. Sperm counts could be suppressed as low as 3 million per milliliter (for comparison, the threshold for male sub-fertility is 15 million per milliliter), and most of these cells could no longer swim. When applied consistently, the method proved to be effective at preventing pregnancy. The catch was that the special underwear had to be worn during all waking hours: about 16 hours a day to be effective.

Wearing funky underwear never caught on as a birth control technique. Men are famously loyal to their favorite style of undies, not to mention suspensories sound uncomfortable.

Why sperm are sensitive to heat

For unknown reasons, developing sperm are much more sensitive to heat than all of the rest of the cells in your body. Temperatures above about 95⁰F activate a protein called Heat Shock Factor in developing sperm. If activated for a sufficient amount of time, Heat Shock Factor will cause the developing sperm to die before they are finished. In comparison, other cells require sustained temperatures in excess of 105⁰F for activation of Heat Shock Factor. This difference in temperature sensitivity is what allows heat exposure to reduce sperm count while leaving the rest of the body unharmed.

Sperm take about 70 days to fully develop within the testicles. Any interruptions during this development process can reduce sperm count. However, sperm cells that are nearly complete appear to be more temperature resistant than immature cells. For this reason, it takes at least 3 weeks for heat exposure to have an effect on semen quality as the mature cells are cleared out. This is also the reason why a sustained period of heat can have a contraceptive effect for months after exposure. If most developing sperm cells are disabled by heat, it takes some time for the sperm cells to repopulate.

Is it safe to regularly heat your testicles?

Most methods of birth control come with risks and side effects. Applying heat does not involve introducing chemicals into your body or surgery. Preliminary evidence suggests that the various heat methods are safe. All of the men enrolled in Dr. Vogeli’s studies and in the suspensory studies were able to father children later, and none of the children were born with abnormalities. None of the men developed problems with libido (sex drive), and seemed to remain in good health. This suggests that testosterone levels remained normal. The amount of time required to fully recover fertility was between 6 – 18 months, depending on how long the method was employed so coming off of heat-based birth control would take more forward thinking than for some alternatives. A subset of men have been exposed to heat as part of their profession for many years, and there has been no evidence of lasting effects.

That said, there have not been large scale studies to support the safety of the heat method. It is possible that a small number of men would develop problems after continuous use. In one instance, a man who had used the suspensory technique for 8 consecutive years on his own initiative did not fully recover his sperm count for 2 years after discontinuing (although he had a residual count of about 20 million per milliliter). Although evidence suggests that testosterone levels remain normal, long term effects have not received sufficient study. Finally, there is the obvious risk of applying water that is a bit TOO hot to your privates and getting a burn where you don’t want one.

The bottom line: The heat method appears to be safe relative to other methods of birth control, but we need larger studies to say for sure. In the meantime, if you use this method it is at your own risk.

Can heat be used reliably as a form of birth control?

The preliminary data is encouraging. Dr. Vogel and the suspensory researchers both reported 100% contraceptive effectiveness when their methods were applied consistently. However, the number of men who participated in these studies numbers in the dozens in total, so we do not know if it is equally effective for all men. We know that condoms are 98% effective when used as directed, but at this moment cannot put a similar number to the heat method.

That said, the biology behind these techniques seems to be solid. Unlike female fertility, it is possible to check whether a man is fertile by doing a semen analysis. A sperm count below 1 million per milliliter was used as threshold for effective male contraception in a recent study on a potential birth control pill for men. A few adventuresome men have employed a heat method at home, bought a microscope, and reported their results to the world over time. It appears that these men were able to reduce their sperm counts to near zero by dedicated adherence to their respective methods. The recent proliferation of home sperm testing kits may make applying these techniques, and seeing if they worked, more feasible.

Considerations for implementing DIY heat based birth control

To re-iterate, there have not been large scale studies to prove that the heat methods are safe for long term use. Nonetheless, there are few dedicated men who have reported their experiences with heat methods online. These enterprising do-it-yourselfers have reported a variety of techniques ranging from programmable warmers (such as a programmable coffee warmer) for Dr. Vogel’s hot water method to custom undies for the testicle suspension method. A means of testing sperm count at home is also essential equipment for these enthusiasts because it would otherwise not be obvious if the technique was actually working. The tools and information are obviously out there, but it is an experimental technique that you try at your own risk.

There is a great need for more research to see if a heat method could be workable contraception for more men. Not every woman can tolerate extended hormonal birth control, and the side effects are severely underrated. For instance, there is at least one report of a man controlling his fertility for the sake of his hormonal pill-intolerant girlfriend through a rigorous monthly ritual of hot baths. In addition, not every man who wants to control his fertility is ready to take the surgical option and get a vasectomy. Perhaps one day researchers will put in the resources to prove the method to be safe and reliable on a larger group of men.

 

References

Robinson, D, and J Rock (1968) “Control of human spermatogenesis by induced changes of intrascrotal temperature.” Journal of the American Medical Association 204(4): 80-7.

Steinberger, E, and WJ Dixon (1959) “Some observations on the effect of heat on the testicular germinal epithelium.” Fertility and Sterility 10(6): 578-95.

Thonneau, P, L Bujan, L Multigner and R Mieusset (1998) “Occupational heat exposure and male fertility: a review.” Human Reproduction 13(8): 2122–5.

Vogeli, M (1954) “Data on the thermic method for temporary male sterilization.” Unpublished. Smith College Archives.
Vogeli, M (1956) “Contraception through temporary male sterilization.” Unpublished. Smith College Archives.

Mieusset, R, and L Bujan (1994) “The potential of mild testicular heating as a safe, effective and reversible contraceptive method for men.” International Journal of Andrology 17: 186-191.

Mieusset, R, L Bujan, A Mansat, H Grandjean and F Pontonnier (1991) “Heat induced inhibition of spermatogenesis in man.” In Zorgniotti (ed.) Temperature and Environmental Effects on the Testes. Plenum Press, NY.

Mieusset, R, L Bujan, A Mansat, F Pontonnier and H Grandjean (1987) “Hyperthermia and human spermatogenesis: enhancement of the inhibitory effect obtained by ‘artificial cryptorchidism’.” International Journal of Andrology 10: 571-80.