Evidence check
Infrared sauna detox: what sweating does, and doesn't, remove
"Detox" is one of the most repeated claims in sauna marketing. Here is the short answer on infrared sauna detox: sweat does contain measurable trace metals and some pollutants, but no study we could find has shown that a sauna removes a meaningful amount of them or lowers the levels in your body. That work falls mainly to your kidneys and liver.
This guide checks the claim against the studies that actually measured sweat, and tests the "percent of toxins" figures you may have seen. Sauna Republic sells infrared saunas, and we would rather you buy one for what it does offer than for a promise the evidence does not support.
What sweat is made of
Sweat is about 99% water, according to Cleveland Clinic, with electrolytes and "very low levels of toxins like heavy metals and BPA" (bisphenol A) in the remaining 1%.
A 2017 review by Baker in Sports Medicine describes the fluid that sweat glands first secrete as "nearly isotonic with blood plasma", carrying sodium, chloride and potassium. Much of the sodium is reabsorbed in the sweat duct, so the sweat reaching the skin is more dilute than plasma. The review concerns exercise sweat in athletes, where it describes sweating as thermoregulatory: a way of controlling body temperature.
How much you sweat in a session
A 2001 review of Finnish sauna bathing by Hannuksela and Ellahham in the American Journal of Medicine reports an average total of about 0.5 kg of sweat per bath, roughly a pound. For far-infrared heat, a 2026 Cardiff Metropolitan University study in Experimental Physiology seated 12 healthy young adults in a two-person far-infrared cabin set to 149°F (65°C) for a single 45-minute session; their sweat rate averaged 1.4 liters per hour. The protocols differ, so the two figures are not directly comparable.
How your body clears wastes
Cleveland Clinic states the division of labor plainly: "Your liver and kidneys are responsible for most of the 'cleansing' you need to stay healthy." According to NIDDK, the NIH's kidney institute, the kidneys filter about 150 quarts of blood a day to clear wastes and excess fluid, yet turn only 1 to 2 quarts of it into urine. MedlinePlus, from the U.S. National Library of Medicine, notes that the liver helps the body "remove poisons". Sweat carries some substances, but it is not where the body's main filtering happens.
Heavy metals in sweat: what the studies found
Researchers can detect metals such as arsenic, cadmium, lead and mercury in sweat, usually in micrograms (millionths of a gram) per liter. These are the five papers we could verify, with what each did not measure.
Sears 2012: a systematic review of metals in sweat
In a systematic review in the Journal of Environmental and Public Health, Sears and colleagues included 24 of 122 records on toxic elements in sweat published through March 2011. Arsenic, cadmium, lead and mercury were measurable in sweat. Among people with "higher exposure or body burden", sweat was generally more concentrated than blood plasma or urine, and in that group loss through the skin "could match or surpass urinary daily excretion". But populations and methods "varied widely", and the only sauna evidence the abstract mentions is one case report in which mercury levels "normalized with repeated saunas"; a single case cannot show cause and effect. The authors wrote that "sweating deserves consideration for toxic element detoxification" and called for "appropriately sized trials".
Genuis 2011: the BUS study of 20 people
The Blood, Urine, and Sweat (BUS) study by Genuis and colleagues, in Archives of Environmental Contamination and Toxicology, tested samples from 20 people, 10 healthy and 10 "with various health problems", for about 120 compounds. Toxic elements appeared "to differing degrees" in all three fluids, and the authors wrote that many "appeared to be preferentially excreted through sweat". The abstract describes no control group and no before-and-after measurement of body levels, and it does not state how sweat was induced, so it is not evidence about infrared saunas, although you may see it cited as such.
Kuan 2022: sauna-cabinet sweat vs exercise sweat
In the only controlled comparison of sauna and exercise sweat for metals that we found, published in the International Journal of Environmental Research and Public Health, Kuan and colleagues had 12 university students sweat twice: running on a treadmill and sitting in a 113°F (45°C) sauna cabinet, with samples taken after 20 minutes of continuous sweating. Sauna-cabinet sweat held significantly less nickel, lead, copper and arsenic per liter; lead averaged 4.9 micrograms per liter against 52.8 in exercise sweat, and mercury did not differ significantly. Sweat rates were nearly equal, and the authors suggested that "a static hot environment may cause a higher proportion of water in sweat". They call the sample "relatively small", the cabinet type is not specified or described as infrared, and blood and urine were not measured.
Siquier-Coll 2020: nine heat sessions at 212°F
A 2020 study in the Journal of Thermal Biology divided 29 healthy men into a control group of 14 and a heat group of 15 that completed nine heat sessions at 212°F (100°C). Sweat was collected after maximal exercise tests at 108°F (42°C), which both groups did. After the heat sessions, sweat lead was higher in the heat group than in the controls, and urinary lead excretion rose. The authors concluded that "heat exercise and constant exposure to heat can be a valid method to increase the excretion of toxic metals", but also wrote that the effect "should be deepened", meaning studied further. The study included men only, nothing in the abstract indicates infrared, and it reported excretion rather than any change in body burden or health.
Cho 2022: the one infrared study used near infrared
The only infrared-specific study of toxic elements in sweat we found, by Cho and colleagues in Environmental Science and Pollution Research (published online in 2022), analyzed sweat from 22 people using a water-filtered infrared-A sauna. It reported higher element concentrations than in sweat from "conventional activities, such as exercise or the use of wet sauna". Infrared-A is near infrared, not the far-infrared type most home cabins use, although you may see the paper cited as a far-infrared study. Only the abstract was available to us, and it neither explains how the comparison was made nor reports whether levels in the body changed.
The five papers side by side
| Paper | Participants | How sweat was produced | What it reported | What it did not show |
|---|---|---|---|---|
| Sears 2012 (review) | 24 reports; mixed groups | Varied; abstract cites one sauna case report | Arsenic, cadmium, lead and mercury measurable | Lower body levels from sauna use |
| Genuis 2011 | 20 people; no control group described | Not stated in the abstract | Toxic elements in blood, urine and sweat | Body levels before and after |
| Kuan 2022 | 12 students | Treadmill vs 113°F (45°C) sauna cabinet | Less nickel, lead, copper and arsenic per liter in cabinet sweat | Blood, urine or body levels |
| Siquier-Coll 2020 | 29 men (15 heat, 14 control) | Exercise tests at 108°F (42°C); heat group also had nine 212°F (100°C) sessions | Higher sweat lead; urinary lead excretion rose | Body burden or health outcomes |
| Cho 2022 | 22 people | Near-infrared (IR-A) sauna | Higher concentrations than "conventional activities" | Far-infrared data, amounts or body levels |
Concentration is not the same as amount removed. A figure in micrograms per liter describes one sample. How much leaves the body depends on how much sweat or urine is produced, and over how long. None of the four original studies above measured whether levels in the body fell, and none reported a health outcome.
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Get PricingInfrared vs traditional sauna sweat
Claims about infrared sauna toxins often come with numbers: infrared sweat is "15-20% toxins", or an infrared sauna removes "seven times more toxins". We could not trace either figure to a primary source, and we found no study comparing infrared and traditional sauna sweat directly. The two closest studies point in different directions, and both measured concentration, not amount removed: Cho's near-infrared sweat was more concentrated than sweat from "conventional activities", while Kuan's sauna-cabinet sweat held less metal per liter than exercise sweat.
The percentages also fail simple arithmetic. Sweat is about 99% water, so everything else in it, electrolytes included, makes up about 1%. By our calculation, the five metals in Kuan's sauna-cabinet sweat total about 172 micrograms per liter, mostly copper, which Cleveland Clinic lists among the trace minerals in sweat. A liter of sweat weighs about 1,000 grams, so that is roughly 0.00002% by weight; 15% would be about 150 grams per liter, some 870,000 times more.
A Cleveland Clinic overview notes that infrared saunas "typically land between 110 F and 135 F" (about 43°C to 57°C), against 150°F to 195°F (about 66°C to 91°C) for traditional saunas, and you may read that this gentler heat, or infrared's "penetration", draws out stored toxins. The International Commission on Non-Ionizing Radiation Protection (ICNIRP) describes infrared reaching into skin to depths from several millimeters for near infrared (IR-A) to "superficial absorption" for far infrared (IR-C). We found no study showing that either band removes more pollutants than other ways of sweating.
Why the detox idea persists
The appeal is easy to see: sweat is visible, a hot session feels like effort, and "sweating out toxins" sounds intuitive. McGill University's Office for Science and Society observes that "the wellness world has embraced saunas", infrared ones included, as a way to sweat out "ill-defined toxins". Three things keep the idea going.
Official sources are more cautious. The NIH's National Center for Complementary and Integrative Health (NCCIH) lists "using a sauna" among the approaches that "detoxification" programs may involve and says research on those programs in people amounts to "only a small number of studies"; some reported positive results, but NCCIH judges the studies "of low quality". Cleveland Clinic says there is "not enough scientific evidence to prove that sweating excessively—through exercising or using a sauna—purifies your body". McGill is blunter: "With the exception of medical interventions following genuine intoxication, the idea of detoxing is not based in science."
If you are worried about toxic exposure
If you have a specific concern, such as a known exposure at work or at home, see a clinician rather than extending your sessions. Metals can be measured in blood and urine, and a clinician can judge whether testing makes sense for you. According to NCCIH, the CDC recommends chelation therapy, a chemical procedure for removing toxic metals from the body, "in some specific serious cases". A sauna is not a substitute for medical care.
Water weight and hydration
The weight you lose in a session is water. Quoted by Cleveland Clinic, family medicine physician Amy Zack, MD, puts it directly: "you will lose water weight, but that is not weight loss, that is dehydration." With rehydration, she adds, the drop "won't be sustained". In the Cardiff study, participants' plasma volume, the fluid part of the blood, was 11.6% lower on average after the 45-minute session.
What an infrared sauna can offer, and how to choose one
Set the detox claim aside and an infrared sauna still delivers heat, a quiet place to sit and a routine you enjoy. That is a sound reason to buy one; on the evidence above, detox is not. For what the research does and does not support, see our infrared sauna benefits guide. Our guide to what to bring to the sauna covers the small comforts.
Clearlight Premier and Sanctuary. Clearlight is the primary infrared brand Sauna Republic carries. The Premier is far infrared only, at roughly 6 to 14 microns; the Sanctuary adds True Wave Full Spectrum heaters that also emit near and mid infrared. Premier IS-1, IS-2 and Sanctuary 1 run on a standard 120V, 15-amp outlet, Premier IS-3 and Sanctuary 2 need a dedicated 120V, 20-amp circuit, and Sanctuary 3, 5, C and Retreat need a dedicated 240V circuit. A two-person Sanctuary was the cabin in the Cardiff study above; Clearlight supplied it, and the authors state that the company had no role in the study's design, conduct, analysis or interpretation. Compare the lines in our Sanctuary vs Premier guide and Clearlight saunas buying guide, or browse Clearlight indoor saunas.
The Clearlight Curve for small spaces. Where a cabin will not fit, the Clearlight Curve is a far-infrared sauna dome; our Curve dome guide has the details.
Finnmark Trinity hybrids. The Finnmark FD-4 Trinity (two people) and FD-5 Trinity XL (three to four people) pair infrared heaters with a Harvia traditional heater and add a 650 nm red light with chromotherapy. Finnmark gives 170°F for infrared sauna bathing and does not state a maximum for the traditional heater; the FD-5's 240V Harvia heater is listed as "Electrician Required". For more options, see our best indoor saunas guide; for how infrared and traditional heat differ, see our Finnish sauna vs infrared sauna comparison.
Frequently asked questions
Do saunas detox your body?
No study we found has shown that they do, infrared included. Sweat carries trace metals at microgram-per-liter levels, but the studies are small, mostly report concentrations rather than amounts, and none of the original studies measured whether body levels fell.
Do you sweat out heavy metals in a sauna?
Trace amounts appear in sweat, which is not the same as meaningful removal. In the one controlled comparison we found, sweat from a 113°F (45°C) sauna cabinet held less nickel, lead, copper and arsenic per liter than exercise sweat, and no study we found showed that sauna sweating lowers these metals in the body.
Is infrared sweat different from traditional sauna sweat?
We found no study comparing them directly. The "15-20% toxins" and "seven times more toxins" figures have no primary source we could trace, and measured metals in sweat are in micrograms per liter, a tiny fraction of one percent. The one infrared study we found used near infrared, not the far infrared most home cabins use.
Does sweating help your liver or kidneys?
None of the studies reviewed here tested that. The kidneys filter about 150 quarts of blood a day (NIDDK), the liver helps "remove poisons" (MedlinePlus), and Cleveland Clinic credits the two organs with most of the "cleansing" the body needs.
How much weight do you lose in a sauna session?
The drop on the scale is water: about 0.5 kg (about a pound) of sweat in a Finnish sauna bath, according to a 2001 review, or "a pint of sweat during a short stint in a sauna", according to Harvard Health Publishing. Cleveland Clinic calls it dehydration, and it returns once you rehydrate.
How much should I drink after a sauna?
Harvard Health Publishing suggests "two to four glasses of cool water after each sauna", and Cleveland Clinic advises drinking water before and after. After a heavy sweat, replace electrolytes too, and skip alcohol. If a medical condition or medication affects your fluid balance, ask your doctor.
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Clearlight, Sanctuary, Premier, True Wave and Curve are trademarks of Sauna Works, Inc., dba Clearlight Infrared. Sauna Republic is an authorized Clearlight dealer. Finnmark and Harvia are trademarks of their respective owners. This article is for educational purposes and is not medical advice. Clearlight describes its products as general wellness products; their statements have not been evaluated by the FDA, and they are not intended to diagnose, treat, cure or prevent any disease. If you are pregnant, managing a medical condition or taking medication, consult a healthcare professional before sauna use, and follow the manufacturer's safety guidance.
