The claim that ice baths increase testosterone has become one of the most repeated ideas in cold therapy. You’ve heard it on a podcast, seen it in a product caption, or read it on a page selling cold plunges. The idea is intuitive: something that demands this much discomfort should produce a powerful hormonal reward.
But when you line up the human studies from 1991 through to 2025, the evidence points in the opposite direction. Cold water immersion does not raise testosterone. The strongest available data shows it lowers it.
What the studies found
1991: The foundational study
The earliest relevant data comes from a 1991 study by Sakamoto and colleagues, which measured hormonal responses to exercise and cold water stimulation in young men. Exercise increased testosterone by about 20.8%. Cold water exposure decreased it by 10%.
One detail is worth pausing on. During cold exposure, luteinising hormone (LH), the signal the brain sends to the testes to produce testosterone, rose by 22.1%. But the testes didn’t respond. Cold stress may activate the hormonal signalling chain without the downstream production following through.
2019: The post-exercise finding
For anyone using ice baths as part of a training routine, the most relevant study is a 2019 trial by Earp and colleagues, published in the European Journal of Applied Physiology. Men performed resistance exercise designed to provoke a testosterone response, then were assigned to either cold water immersion or a control condition.
Men in the control group experienced a 9.2% increase in free testosterone after training. Those who underwent cold water immersion saw a 0.5% decrease. If you’re lifting weights partly for the hormonal stimulus and then climbing into an ice bath, the cold may be suppressing exactly the response your training produced. A 2024 meta-analysis in the European Journal of Sport Science now treats this testosterone blunting as an established mechanism through which cold water immersion may impair muscle hypertrophy.
2025: The clearest data yet
The most recent finding comes from Teleglow and colleagues, published in PLoS ONE in 2025. Thirteen young, healthy men underwent cold water immersion below 4°C. Testosterone decreased with a p-value of 0.000037. Values remained within normal reference ranges, so this isn’t a clinical alarm, but as a direct test of whether ice baths raise testosterone, it is about as clear as the data gets.
What about the studies people cite in support?
A 2021 study by Podstawski found a roughly 5% increase in testosterone after sauna followed by cold water immersion. That increase was not statistically significant, and the protocol included sauna, making it impossible to attribute the change to cold exposure alone.
A 2024 preprint by Gillette and McCutchin reported testosterone elevation, but it remains unpublished in a peer-reviewed journal, used a sample of eight men, and involved immersion durations of 25 to 35 minutes, far beyond any standard cold plunge protocol. Anecdotal reports, including a widely shared case study from Morozko Forge, describe individual testosterone increases, though even the author has acknowledged no clinical trial supports the claim.
As Legacy’s fertility specialists put it: “There’s no evidence to prove ice baths are an effective way to improve testosterone, and most available evidence shows cold exposure means lower T.”
Why the myth persists
If the evidence is this consistent, how did the claim become so widespread? Three specific misunderstandings explain most of it.
Rat studies, applied to humans. Some early animal research found that cold exposure could increase testosterone in rodents. Rats thermoregulate differently from humans, and hormonal responses in animal models frequently fail to translate. In their original context, the findings held up, but they were never confirmed in human trials. That distinction got lost somewhere between the lab and the podcast.
Scrotal cooling, confused with ice baths. There is evidence that cooling the testes specifically, using targeted devices rather than whole-body immersion, may support sperm production. Spermatogenesis is temperature-sensitive, which is why the testes sit outside the body. But scrotal cooling for fertility is a different intervention from sitting in an ice bath, targeting a different process through a different mechanism. Over time, the two got conflated, and the fertility angle bled into testosterone claims it never supported.
The noradrenaline leap. Cold exposure reliably produces a large spike in noradrenaline, which drives alertness, focus, and energy. The felt experience of a cold plunge, that surge of vitality and sharpened attention, is real and measurable. For many people, it seems like what a testosterone boost should feel like. A logical leap from “I feel powerful” to “my testosterone must be elevated” is understandable, but the biochemistry doesn’t support it. That power comes from an entirely different hormonal cascade.
What cold exposure actually does to your hormones
Cold exposure is a powerful hormonal intervention. It just works on different hormones than the ones this audience arrived asking about.
By far the best-documented response to cold water immersion is a dramatic rise in noradrenaline. A rigorous 2025 study by Braunsperger and colleagues, published in Scientific Reports, measured increases of 127% to 144% after ice baths, among the largest acute hormonal shifts you can produce without pharmacological intervention. Braunsperger’s team also measured adrenaline and cortisol but did not measure testosterone, an informative choice by researchers focused on what cold exposure is known to affect.
Andrew Huberman, a neuroscientist at Stanford University whose public work on cold exposure protocols has shaped much of the current conversation, has emphasised noradrenaline and dopamine as the hormonal mechanisms behind cold exposure’s benefits. The alertness, the sustained mood elevation, the calm focus that follows a cold plunge: these map onto noradrenaline and dopamine pathways, and the evidence supporting them is strong and consistent.
How to use this
If you’re training for muscle growth and using cold water immersion immediately after lifting, the Earp data suggests separating the two, giving your post-exercise hormonal response time to do its work before you get in the cold. If you’re using ice baths for mental sharpness, stress tolerance, and mood, you’re backed by some of the strongest evidence in the entire cold therapy literature.
And if you’re choosing a cold plunge because someone told you it would raise your testosterone, you now know more than the person who told you that.
Cold exposure earns its place in a recovery practice on the strength of what it genuinely does. A 127% noradrenaline surge is not a consolation prize. It’s the main event, and it was there all along.
