Short answer
No. There is no good evidence that cold plunges, ice baths or cold showers raise sperm count or testosterone. The cooling studies people quote used gentle overnight airflow for 12 weeks in men with low sperm counts, which is a very different thing from three minutes in a tub of ice. Plunge if you enjoy it. Just don't do it for your sperm.
Bit of a buzzkill for the ice-bath crowd, we know. Here's how the idea got started, and where it falls apart.
Why do people think cold helps sperm?
Because the first half is true. Testicles work best around 2 to 4°C below core body temperature (Maroto et al., 2025), and heat does knock sperm production. In one small study, ten men who had two 15-minute saunas a week for three months saw their sperm count and motility drop sharply, then fully recover within six months of stopping (Garolla et al., 2013). More on that in our sauna and sperm guide.
The leap is from "heat is bad" to "freezing must be brilliant". That second step has almost nothing behind it.
Do cold showers or ice baths raise testosterone?
Traylor et al., 2026: cold showers in 11 athletes
What the research found: Eleven male current or former college athletes took 10-minute cold showers at 17°C on four days running. Some men's salivary testosterone went up, some went down, several barely moved, and overall there was no significant change (Traylor et al., 2026).
What it doesn't prove: Four days and eleven men is tiny. It can't rule out a small effect, but it certainly doesn't show a boost.
The wider picture is no better. A 2025 review of alternative men's health therapies found cold water immersion had inconsistent effects on testosterone, in studies limited by small samples and short follow-up (Qaoud et al., 2025). A 2026 review of testosterone strategies for athletes went further and noted that cold-water immersion may lower testosterone (Lazarev et al., 2026).
Do ice baths improve sperm count?
We searched the medical literature in September 2026 and couldn't find a single human study measuring semen quality after cold plunges, ice baths or cold showers. The studies that get quoted are about something else entirely.
Jung et al., 2001 and 2005: overnight scrotal cooling
What the research found: In men with low sperm counts, a gentle air stream cooled the scrotum by about 1°C every night. After 12 weeks, sperm concentration and total count rose significantly (Jung et al., 2001). A follow-up in 20 men with low counts and a history of undescended testicles used a small pump to blow air around the groin nightly, lowered scrotal temperature by a median 0.8°C, and again saw concentration and count rise by weeks 8 and 12 (Jung et al., 2005).
What it doesn't prove: Both studies were in men with existing sperm problems, not healthy men chasing an upgrade. The 2001 study paired cooling with cutting other heat habits, and the 2005 study compared against a control group assembled afterwards. The 2005 authors themselves called for a controlled study of pregnancy rates. And both used hours of mild cooling, not minutes of intense cold. A systematic review found too little evidence for firm conclusions about scrotal cooling and fertility (Nikolopoulos et al., 2013).
What does "cooling" actually mean in the research?
A degree or so, held for a long time. Beyond the Jung studies, one trial of a commercial cooling underwear lowered median scrotal skin temperature by 0.7°C, without measuring sperm (Zumstein et al., 2021). Nobody in this research was aiming for cold. The goal is to stop things running hot, which is why the boring stuff (less sauna, less laptop-on-lap, looser fit) matters more than any plunge. Our guide to icing your testicles covers the DIY versions.
Is it safe to ice your balls or plunge in ice water?
Cold has real downsides. Ice packs can cause cold burns: one case report, titled "Frostbite at the gym", describes a partial-thickness burn from an ice pack (O'Toole and Rayatt, 1999). Cold water immersion is also studied as a precursor to drowning, cardiac arrest and hypothermia (Tipton et al., 2017). If you have a heart condition, talk to your GP before plunging.
- Never put ice or anything frozen directly on skin.
- Stop if you go numb, it hurts or your skin changes colour.
- Don't plunge alone.
- Cut heat first: saunas, hot tubs, long baths, a laptop on your lap.
- Trying to conceive? A semen analysis via your GP beats any protocol.
So what should you do instead?
Keep your core hot if you like. Keep them cool, not frozen. NICE says raised scrotal temperature is linked with reduced semen quality, but it's uncertain whether measures like looser underwear improve fertility (NICE, 2026). Start with the free five-question Heat Check to see where heat creeps into your week. It's an educational quiz, not a fertility test.
Yes, we make a thing: a merino boxer with a reusable cooling insert that sits in a sleeve, so it never touches bare skin. We sell it as comfort. It wasn't used in any study here and hasn't been shown to improve sperm, testosterone or fertility. If that's your kind of cool, you can reserve a founder kit. For every source we lean on, see our research hub.
Frequently asked questions
Do cold showers increase sperm count?
There's no human study showing that. The only recent trial we found looked at testosterone and saw no significant change.
Does an ice bath lower testosterone?
Possibly. One 2026 review says cold-water immersion may decrease testosterone, but the studies are small and mixed.
Is scrotal cooling proven to help fertility?
No. Overnight-cooling studies saw better sperm counts in men with low counts, but a systematic review found too little evidence for firm conclusions about fertility.
How cold is too cold for testicles?
Anything that goes numb or hurts. The research used cooling of about 1°C, not ice.
References
- Maroto M et al. Mechanisms of hormonal, genetic, and temperature regulation of germ cell proliferation, differentiation, and death during spermatogenesis. Biomolecules, 2025. PMID 40305231
- Garolla A et al. Seminal and molecular evidence that sauna exposure affects human spermatogenesis. Hum Reprod, 2013. PMID 23411620
- Traylor DA et al. A four-day cold shower protocol does not increase salivary testosterone in a small cohort of male athletes. Health Sci Rep, 2026. PMID 42064114
- Qaoud Y et al. A systematic appraisal of emerging alternative therapies in men's health and wellness. Can Urol Assoc J, 2025. PMID 41406341
- Lazarev A et al. Testosterone-optimizing strategies in athletes. Sports Health, 2026. PMID 41630126
- Jung A et al. Improvement of semen quality by nocturnal scrotal cooling and moderate behavioural change to reduce genital heat stress. Reproduction, 2001. PMID 11277880
- Jung A et al. Improvement of semen quality by nocturnal scrotal cooling in oligozoospermic men with a history of testicular maldescent. Int J Androl, 2005. PMID 15811070
- Nikolopoulos I et al. Scrotal cooling and its benefits to male fertility: a systematic review. J Obstet Gynaecol, 2013. PMID 23654310
- Zumstein V et al. Special underwear for cyclic cooling significantly decreases scrotal skin temperature. Cent European J Urol, 2021. PMID 34729240
- O'Toole G, Rayatt S. Frostbite at the gym: a case report of an ice pack burn. Br J Sports Med, 1999. PMID 10450486
- Tipton MJ et al. Cold water immersion: kill or cure? Exp Physiol, 2017. PMID 28833689
- NICE. Fertility problems: assessment and treatment (NG257), 2026. nice.org.uk
Last reviewed 24 September 2026.
