Avoiding heat has become almost cliché fertility advice to any couple starting out. “Watch out for hot tubs” “Switch to looser underwear.” As we like to say, “Don’t cook your balls!”
Sperm are more sensitive to heat than other cells in the body. When sperm is exposed to temperatures above 95 degrees Fahrenheit, they express a protein called Heat Shock Factor which can cause them to develop abnormally or even die before they finish maturing. So, does icing your balls improve fertility? Let’s review the research…
Is icing your balls effective at improving male fertility?
Research on testicular cooling as a potential therapy for male infertility began in the mid 1960’s. Researchers had newly discovered that there was a correlation between high scrotal temperature and low sperm count and were curious to see if interventions aimed at lowering the temperature would cause sperm count to increase. Most studies revealed a statistically significant improvement in sperm count after several weeks of cooling. Some also showed improvements on motility, morphology and pregnancy rates.
One of the first studies to explore the effects of temperature on sperm quality took a group of men with normal sperm counts and exposed them to heat from a 150-watt light bulb for 30 minutes which raised scrotal temperature by about 5 degrees Fahrenheit for 14 consecutive days. Sperm counts dropped. 12 days later the sperm counts returned to normal. They then iced their balls for 30 minutes for 14 consecutive days, lowering scrotal temperature about 12 degrees. Sperm counts nearly tripled. They then repeated the experiment with men who had low sperm counts. They found a similar pattern but men with lower counts responded less predictably. Some showed little improvement on semen quality, some showed dramatic improvement.
Subsequent studies with infertile men used a variety of cooling methods and showed similar results. Some men responded really well, others only showed mild improvements. One study followed 64 men who had been unable to conceive for more than 2 years. Men wore a cooling device for 16 weeks. 42 of them saw improvement in semen quality, 11 of them conceived. Another study included 25 patients who were infertile after 6 years of trying. In this study 16 men showed improved semen quality, 6 conceived.
Reviewing multiple studies, it appears that dramatic improvements occurred in at least 50% of the patients. In most cases, sperm count showed the most marked improvement with up to a doubling or tripling of baseline in many patients. So, while it doesn’t work for everyone, there is solid evidence that it can help.
The best way to cool your balls: a guide to manly cooling
Since the research on testicular cooling is limited, there is not a definitive “best way” to cool your balls to improve your fertility. However, looking a bit deeper at the studies can give us some insight into what researchers believe are important factors for effective cooling.
How cold does it need to get?
Studies around heat and fertility showed a decline of semen quality at temperatures above 95 degrees Fahrenheit. Conversely, there have been improvements shown in patients who can keep scrotal temperature below 93 degrees. Different tactics were employed to reach this goal. Some studies exposed patients to cooler temperatures for shorter periods of time while others had continuous cooling for up to 24 hour period.
Some good rules of thumb:
- Be comfortable: The goal is to cool, not freeze your balls.
- The milder the temperature drop, the longer the exposure should be.
Best methods for cooling your balls
Reading the studies was entertaining. Some of the researchers rigged up ridiculous devices that gently blew cool air through a tube surrounding the scrotum that men wore while sleeping. Others used ice packs, special underwear or other devices designed to provide 24-hour cooling. Thankfully, you don’t have to be enrolled in a study or wear a researcher’s funky gadget to get the benefits of testicular cooling. A couple of guys who were dealing with infertility designed some nice briefs that contain special pockets for gel packs that are designed to snuggly fit and cool. Gel packs can be changed out regularly to make cooling convenient and discreet. We think they are worth the price for the effectiveness and convenience.
However, if you want to try cooling before making an investment, there are a couple of DIY options
- Bag of ice or frozen peas applied at regular intervals
- Sleeping in the nude with cool air blowing
- Baths, cool showers or other regular exposure to cold water
- Other ideas? Leave them in the comments…
How often do I need to cool?
Most studies exposed men to cooler temperatures at least daily. The duration of a cooling session ranged from an hour or two to 24-hour continuous exposure. The most common procedure was to use an experimental device to provide continuous cooling while the patient slept. As mentioned above, it is possible to get similar effects by using colder temperatures for shorter periods. The “guide to manly cooling” included in the Snowballs package recommends cooling at least 4 times a day for 30 minutes.
How long do I need to cool before I see results?
The studies we reviewed tested men after 2 weeks, 8 weeks, 12 weeks and 20 weeks. Strongest results were reported after 12 weeks indicating this is a bit of a commitment. Biologically, this makes sense. A sperm cell takes 72 days to fully develop. Because of this, urologists generally recommend a period of 3 months minimum before formally repeating a semen analysis on men who are receiving any sort of treatment for infertility. Anecdotally, we have heard stories from DIY sperm trackers, that they have seen initial improvements in sperm count after a few weeks of treatment. Our hypothesis is that cooling not only helps with generation of new sperm but prevents sperm that are in development from prematurely dying. Overall, it is possible to see changes in a couple of weeks but don’t get discouraged if it takes longer. Give yourself a good 3-6 months to see if your swimmers respond.
Can icing your balls cause any damage?
Several men have submitted this question via email. We scanned the literature and didn’t see any adverse effects reported in any of the studies that we reviewed. We’ve also asked urologists and the founders of Snowballs if they have ever heard of any one hurting themselves. So far, we haven’t heard of anyone doing damage. Our recommendation is, if it starts to feel uncomfortable adjust the temperature so that it is not quite so cold.
Good luck, gentleman.
- Jung A1, Schuppe HC. Influence of genital heat stress on semen quality in humans. Andrologia. 2007 Dec;39(6):203-15.
- Hjollund NH1, Storgaard L, Ernst E, Bonde JP, Olsen J. Impact of diurnal scrotal temperature on semen quality. Reprod Toxicol. 2002 May-Jun;16(3):215-21.
- Jung A1, Eberl M, Schill WB. Improvement of semen quality by nocturnal scrotal cooling and moderate behavioural change to reduce genital heat stress in men with oligoasthenoteratozoospermia. Reproduction. 2001 Apr;121(4):595-603.
- Jung A1, Schill WB, Schuppe HC. Improvement of semen quality by nocturnal scrotal cooling in oligozoospermic men with a history of testicular maldescent. Int J Androl. 2005 Apr;28(2):93-8.
- Zorgniotti A W, Sealfon A I. 1988. “Measurement of intrascrotal temperature in normal and subfertile men.” Journal of reproduction and fertility 82 (2): 563-6.
- Zorgniotti A W, Cohen M S, Sealfon A I. 1986. “Chronic scrotal hypothermia: results in 90 infertile couples.” The Journal of urology 135 (5): 944-7.
- Zorgniotti A W, Sealfon A I. 1984. “Scrotal hypothermia: new therapy for poor semen.” Urology 23 (5): 439-41.
- Mulcahy JJ. Scrotal hypothermia and the infertile man. J Urol. 1984 Sep;132(3):469-70.
- Zorgniotti AW, Sealfon AI, Toth A. Further clinical experience with testis hypothermia for infertility due to poor semen. Urology. 1982 Jun;19(6):636-40.
- Zorgniotti AW, Sealfon AI, Toth A. Chronic scrotal hypothermia as a treatment for poor semen quality. Lancet. 1980 Apr 26;1(8174):904-6.
- Zorgniotti A W. 1980. “Testis temperature, infertility, and the varicocele paradox.” Urology 16 (1): 7-10.
- Lazarus B A, Zorgniotti A W. 1975. “Thermoregulation of the human testis.” Fertility and sterility 26 (8): 757-9.
- Derek Robinson, MD; John Rock, MD; Miriam F. Menkin, MA Control of Human Spermatogenesis Intrascrotal Temperature JAMA. 1968;204(4):290-297. doi:10.1001/jama.1968.03140170006002