TL;DR
- Every claim below is checked against the original source.
- The Cochrane review of whole-body cryotherapy for muscle soreness found four trials with 64 people. All but four were men. Every outcome was graded «very low» quality.
- None of those four trials watched for side effects. Cochrane flagged that as a problem, since the exposure is below −100°C.
- The FDA’s live page says the healing benefits of whole-body cryotherapy are unconfirmed. Its earlier, harsher notice has since been removed from the site.
- Most walk-in studios sell a different machine from the one in the research: head-out nitrogen cabins, not the breathable-air chambers the trials used.
- In a 12-week training study, the men who took cold recovery gained less strength and less muscle than the men who cycled gently instead.
- The mood claim has the field’s most interesting numbers and its own honest warning: the reviewers added a bias check for researchers invested in the therapy working.
- The best pooled evidence says cold does reduce muscle pain, and does not improve performance.
The pitch is impossible to improve on. You step into a chamber, liquid nitrogen vapour drops the air to somewhere near minus 130 degrees, and three minutes later you step out repaired.
Footballers do it. Recovery studios sell it by the ten-pack. The physiological story is plausible: extreme cold constricts blood vessels, blunts inflammation, and inflammation is what makes you sore.
So when the Cochrane Collaboration went looking for the trials, it should have found a lot of them.
It found four. Sixty-four participants in total. All but four of them men, average age 23, all in laboratories (Costello et al., 2015).
Four trials, and what was wrong with each
The reviewers searched nine databases, trial registers, conference proceedings and reference lists, then hand-searched journals and wrote to experts. What came back was two parallel-group trials with 44 people between them and two crossover trials with 20.
The trials disagreed with each other on almost every parameter that matters: the temperature of the chamber, how long people stayed in, how many exposures they had, and what exercise they had done beforehand. «All four trials had design features that carried a high risk of bias.»
Then the grade. Cochrane rates the certainty of evidence on a four-level scale, and for every single outcome here the answer was the bottom one: very low quality. That is the level at which the review is telling you the true effect is probably substantially different from the estimate.
The soreness numbers themselves show why. At one hour after exercise, the pooled standardised difference was −0.77, which sounds decent, with a confidence interval running from −1.42 to −0.12. At 24 hours it was −0.57, interval −1.48 to 0.33. At 48 hours, −0.58, interval −1.37 to 0.21. At 72 hours, −0.65, interval −2.54 to 1.24.
An interval that crosses zero includes the possibility that the treatment does nothing. Three of those four do. The 72-hour interval is wide enough to include a large benefit and a large harm at the same time.
The comparison that was never run
Here is the finding that should shape what anyone does with this. In the Cochrane review’s own words: «No studies compared WBC with other active interventions, such as cold water immersion.»
Every one of the four trials compared the chamber against rest, or against doing nothing at all. Not one compared it against a bath of cold water, which costs nothing, is available in every home, and has a far larger literature behind it.
That is the question every buyer actually has. A session in a chamber costs somewhere between 40 and 90 dollars in most cities. A cold bath costs the water. Cochrane found nobody had run the head-to-head, and when somebody finally did, the answer went the cheap way.
The indirect evidence is not encouraging for the chamber. A 2024 meta-analysis pooled 18 studies and 499 people across three cold methods (Feng et al., 2024). Cold water immersion significantly reduced muscle pain. Whole-body cryotherapy significantly lowered C-reactive protein, an inflammation marker. Contrast water therapy did nothing measurable at all.
And the summary line, which is the one to keep: «all cryostimulation may have no significant influence on exercise performance». Less sore, not faster.
What the regulator says, and what it stopped saying
In the United States, cryotherapy chambers occupy a strange legal space. They are sold everywhere and cleared for nothing.
The FDA’s current live guidance on cold therapy is brief on the subject and unambiguous in tone: «Whole body cryotherapy presents a different set of risks and its healing benefits are unconfirmed» (FDA, 2020).
There used to be more. In 2016 the agency published a consumer update titled «A Cool Trend that Lacks Evidence, Poses Risks», which stated that it had not cleared or approved any of these devices for treating any medical condition and listed frostbite, burns, eye injury and asphyxiation among the hazards. That page now returns a 404. It is still cited in the scientific literature, including by the researchers who disagree with it.
Two machines, one word
Those researchers have a point, and it is the single most useful thing a buyer can learn about this industry.
An international consortium reviewed every documented adverse event in the literature and found the safety debate had been conflating two different devices (Legrand et al., 2023). A whole-body cryochamber is a room filled with chilled breathable air, which you walk into entirely. A partial-body cryosauna is a narrow tub filled with vaporised liquid nitrogen, which you stand in with your head sticking out of the top.
The head is outside for a reason: nitrogen displaces oxygen, and you cannot safely breathe the atmosphere inside the tub. Almost all the research on cryotherapy was done in chambers. Almost every walk-in studio, including the ones quoting that research, uses a nitrogen tub.
The consortium’s tally for true whole-body chambers: five case reports and two randomised trials, 16 documented adverse events in total, mostly minor and transient, across decades of use in Poland, Italy and France. Their conclusion is that risks are within acceptable limits when contraindications are respected.
That is a fair defence of the chamber. It is not a defence of the tub, and it does not answer the efficacy question at all.
Cochrane’s other warning
Buried in the review’s conclusions is a line about safety that is easy to skim past.
«None of the trials reported active surveillance of predefined adverse events.» Not «no adverse events occurred». Nobody looked.
The reviewers spell out why this matters: «The lack of evidence on adverse events is important given that the exposure to extreme temperature presents a potential hazard.»
The field has since started addressing this from the inside. In 2025 an international working group published a consensus list of contraindications for whole-body cryostimulation, built through structured expert rounds (Capodaglio et al., 2025). A treatment that needs a formal contraindication list is a treatment with real physiological force. It is also not the harmless wellness add-on that walk-in pricing implies.
The cold that costs you muscle
There is one more result, and it is the one that changed practice among strength coaches while leaving the recovery-studio market untouched.
Twenty-one physically active men strength trained twice a week for 12 weeks. After every session, half of them sat in cold water for 10 minutes and half did gentle active recovery (Roberts et al., 2015).
Strength and muscle mass increased more in the active recovery group. Isokinetic work rose 19 per cent in the active group and not significantly in the cold group. Type II muscle fibre cross-sectional area rose 17 per cent in the active group and not in the cold group. Myonuclei per fibre rose 26 per cent in the active group and not in the cold group.
A second experiment in the same paper took muscle biopsies and found why. Satellite cells, the repair cells that build new muscle, increased 20 to 50 per cent after exercise with active recovery. With cold, they did not rise the same way. The signalling kinase that switches on muscle protein synthesis was also blunted.
The authors end with a sentence unusual for a physiology paper: «The use of CWI as a regular post-exercise recovery strategy should be reconsidered.»
This was cold water, not a cryotherapy chamber, and the two are not identical. But the mechanism is the one cryotherapy advertises. Blunting the inflammatory response after training is the selling point, and inflammation after training is part of how muscle is built.
Where the evidence is real
A 2025 meta-analysis of 11 randomised trials with 274 participants found that whole-body cryotherapy lowered interleukin-1β and raised interleukin-10 in blood, moving both markers in an anti-inflammatory direction (He et al., 2025).
That is a genuine biological effect, measured properly, and it is worth saying clearly because the debunking instinct overshoots here. Cold does something. The chamber is not theatre.
The gap is between a marker in a blood sample and an outcome in a life. Lower IL-1β is a reason to keep studying the treatment. It is not a reason to believe it heals injuries, treats fibromyalgia, burns fat or extends lifespan, and those are the claims on the walls.
Somebody finally ran the comparison
Since the Cochrane review closed its search, the missing head-to-head has been done, and it is the single most useful result in this literature for anyone deciding where to spend money.
A meta-analysis pooled 13 randomised trials covering 214 physically active adults, searching four databases from 2002 to the end of 2024, and compared cold water immersion directly against whole-body and partial-body cryotherapy (Liu & Ma, 2026).
The bath won. For muscle soreness within 24 hours, cold water immersion beat cryotherapy with a mean difference of 1.07 on the pain scale, no heterogeneity between studies at all. By 48 hours the gap was no longer significant at 0.47.
Cryotherapy took one narrow prize. Jump performance at 24 hours favoured the chamber slightly, standardised mean difference 0.52, which the authors themselves describe as small and fragile, with high heterogeneity between the studies feeding it.
So the question Cochrane could not answer now has a provisional answer, and it is not the one the pricing implies. The cheaper intervention performed better on the outcome people actually book a session for.
The mood claim, and the bias nobody usually measures
Recovery studios increasingly sell cryotherapy for mood rather than muscles: depression, anxiety, «resilience». That literature exists, and the review of it does something quietly admirable.
Three Dutch mental-health researchers searched three databases, screened 196 articles and found ten that qualified, six of them controlled trials, covering 294 people who received cryotherapy (Doets, Topper & Nugter, 2021). Then, assessing risk of bias, they added a dimension that standard tools do not include: allegiance bias, meaning the tendency of researchers who believe in a treatment to find that it works.
The results are striking in both directions. The within-group effect on mental health problems was large, Hedges’ g of 1.63, which in plain terms means the average treated person moved more than one and a half standard deviations. For depressive symptoms it was larger still.
Then the heterogeneity: I² of 93 per cent. That statistic measures how much the studies disagree with one another beyond chance, and 93 per cent is close to the ceiling. When studies of the same treatment produce wildly different answers, the pooled average is a number without a referent.
And the comparison that counts. Within-group change, which includes everything that happens to people over time regardless of treatment, was g = 1.63. Between-group, comparing treated against control, it fell to 0.76. Less than half. That gap is roughly the size of the placebo, the seasonal drift, the attention from clinicians, and the simple fact that people enrolling in a depression study are often at their worst on the day they enrol.
The authors call the result «preliminary evidence» and ask for randomised trials with larger numbers. That is the correct reading, and it is more cautious than any studio website.
Verdicts
«Cryotherapy reduces muscle soreness»: P — Partial. Four trials, 64 men, every outcome graded very low quality, and three of four time points had confidence intervals crossing zero. Cold in general does reduce soreness; the chamber specifically is thinly evidenced.
«Cryotherapy improves athletic performance»: R — Refuted. The 2024 pooled analysis concludes cryostimulation may have no significant influence on exercise performance.
«Cryotherapy is better than a cold bath»: R — Refuted. Cochrane found zero comparisons; a 2026 meta-analysis of 13 trials since found cold water immersion beat cryotherapy for soreness at 24 hours
«Cryotherapy treats medical conditions»: H — Untested for most of the conditions advertised. The FDA’s live position is that the healing benefits are unconfirmed.
«Cryotherapy reduces inflammation»: C — Confirmed at the level of blood markers, in 11 trials and 274 people.
«Cryotherapy helps depression»: P — Partial. Ten studies, 294 people, a large within-group effect that halves when compared against controls, and heterogeneity at 93 per cent. The reviewers call it preliminary.
«Cold recovery after training is harmless»: R — Refuted. Regular cold water immersion after strength training produced smaller gains in strength and muscle size over 12 weeks than gentle active recovery.
The shift: treat cold as a tool for feeling better, not for adapting better, and time it accordingly.
First move: if you are training to get stronger or bigger, keep cold away from your lifting days, or leave several hours between the session and the cold.
Second move: if the goal is soreness relief during a competition week, cold water immersion has the larger evidence base and the smaller bill.
Third move: ask the studio whether the machine is a chamber or a head-out nitrogen tub. Almost all the published research was done in the first, and almost all studios sell the second.
Nitrogen cabins must never be used alone or unsupervised, and people with heart or circulatory conditions, uncontrolled blood pressure or cold-triggered disorders should talk to a doctor first.
The boring bottom line
A treatment sold in every major city on the strength of elite-sport endorsement rests, for its headline claim, on four laboratory trials involving 64 mostly male undergraduates, none of which watched for side effects and all of which Cochrane graded at the bottom of its scale.
Cold does real things. It lowers inflammatory markers, it reduces how sore you feel, and after strength training it appears to cost you some of the adaptation you trained for. What the one direct comparison shows is that the expensive version does it slightly worse than a bath.
Three minutes at minus 130 degrees is an experience. Whether it is a treatment worth its price, now that the bath has beaten it head to head, is a much shorter question.
Sources
- Costello, J. T., Baker, P. R. A., Minett, G. M., Bieuzen, F., Stewart, I. B., & Bleakley, C (2015). Whole-body cryotherapy (extreme cold air exposure) for preventing and treating muscle soreness after exercise in adults. Cochrane Database of Systematic Reviews. Issue 9, CD010789. Four laboratory RCTs, 64 physically active adults, mean age 23, all but four male. All four trials at high risk of bias; evidence for all outcomes graded 'very low' by GRADE. No trial reported active surveillance of predefined adverse events. No study compared WBC with cold water immersion. doi:10.1002/14651858.CD010789.pub2
- Feng, C., Chen, P., Zhang, W., Luo, B., Du, G., Liao, T., & Zheng, C (2024). A evidence-based approach to selecting post-exercise cryostimulation techniques for improving exercise performance and fatigue recovery: a systematic review and meta-analysis. Heliyon. 10(11), e32196. 18 articles, 499 healthy participants (479 male, 20 female), of whom 58 used whole-body cryostimulation. Cold water immersion reduced muscle pain intensity (SMD -0.45); WBC lowered C-reactive protein (SMD -1.36); contrast water therapy showed no significant difference. Conclusion: all cryostimulation may have no significant influence on exercise performance. doi:10.1016/j.heliyon.2024.e32196
- Liu, S., & Ma, Y (2026). Effects of cold water immersion vs body cryotherapy on delayed onset muscle soreness and jump performance following acute strenuous exercise in physically active participants: a systematic review and meta-analysis. Medicine. 105(4), e46781. 13 randomised controlled trials, 214 participants aged 20-47.2, databases searched to 10 December 2024. Cold water immersion significantly more effective than body cryotherapy for DOMS within 24 hours (mean difference 1.07, 95% CI 0.70-1.43, I2 = 0%); not significant at 48 hours (0.47, -0.04 to 0.98). Cryotherapy showed a small and fragile 24-hour jump-performance advantage (SMD 0.52, 0.03-1.02) with high heterogeneity. doi:10.1097/MD.0000000000046781
- U.S. Food and Drug Administration (2020). Cold facts to help avoid injury from water-circulating hot/cold therapy devices. FDA Consumer Updates. Content current as of 09/09/2020. 'Whole body cryotherapy presents a different set of risks and its healing benefits are unconfirmed.' The agency's separate 2016 consumer update on whole body cryotherapy is no longer available on fda.gov (checked 2026-08-29) but is cited in the peer-reviewed literature. fda.gov
- Legrand, F. D., Dugué, B., Costello, J., Bleakley, C., Miller, E., Broatch, J. R., et al (2023). Evaluating safety risks of whole-body cryotherapy/cryostimulation (WBC): a scoping review from an international consortium. European Journal of Medical Research. 28(1), 387. Distinguishes whole-body cryotherapy (breathable chilled air in a chamber) from partial-body cryotherapy (head-out exposure to vaporised liquid nitrogen), which the authors argue has been conflated in earlier FDA and INSERM safety statements. Five case reports and two RCTs yielded 16 documented adverse events for true WBC. doi:10.1186/s40001-023-01385-z
- Roberts, L. A., Raastad, T., Markworth, J. F., Figueiredo, V. C., Egner, I. M., Shield, A., Cameron-Smith, D., Coombes, J. S., & Peake, J. M (2015). Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. The Journal of Physiology. 593(18), 4285-4301. 21 men strength trained for 12 weeks with cold water immersion or active recovery after each session. Strength and muscle mass increased more with active recovery; isokinetic work +19%, type II fibre cross-sectional area +17% and myonuclei per fibre +26% in the active group only. Satellite cell responses and p70S6 kinase phosphorylation were blunted by cold. doi:10.1113/JP270570
- He, J., Zhang, X., Ge, Z., Shi, J., Guo, S., & Chen, J (2025). Whole-body cryotherapy can reduce the inflammatory response in humans: a meta-analysis based on 11 randomized controlled trials. Scientific Reports. 15(1), 7759. 11 RCTs, 274 participants. Serum IL-1beta lower after WBC (SMD -2.08, p < 0.05) and IL-10 higher (SMD 0.78, p < 0.05). Risk of bias assessed with PEDro, certainty with GRADE. doi:10.1038/s41598-025-90396-3
- Doets, J. J. R., Topper, M., & Nugter, A. M (2021). A systematic review and meta-analysis of the effect of whole body cryotherapy on mental health problems. Complementary Therapies in Medicine. 63, 102783. 196 articles screened, 10 included, 6 of them controlled trials, 294 participants receiving WBC. Within-group pooled Hedges' g = 1.63 (CI 1.05-2.21) with I2 = 93%; between-group g = 0.76 (CI 0.17-1.36). Risk of bias scored with ROBINS-I plus an added allegiance-bias dimension. Authors describe the evidence as preliminary. doi:10.1016/j.ctim.2021.102783
- Capodaglio, P., Alito, A., Duguè, B. M., Bouzigon, R., Lombardi, G., Miller, E. D., Verme, F., Modaffari, G., Piterà, P., Ziemann, E., & Fontana, J. M (2025). Contraindications to whole-body cryostimulation (WBC): a position paper from the WBC Working Group of the International Institute of Refrigeration and the multidisciplinary expert panel. Frontiers in Rehabilitation Sciences. 6, 1567402. International consensus process generating an updated contraindication list for whole-body cryostimulation. doi:10.3389/fresc.2025.1567402