“You can sweat out toxins in a sauna.”
Your liver, kidneys and gut clear toxins, not your sweat; sweat carries only tiny traces of metals and chemicals, and a sauna does not detox you.
You do not need to sweat to clean out your body. Your liver, kidneys and gut remove waste every day, and sauna sweat is mostly water and salt. If you enjoy saunas, enjoy them for relaxation, not as a detox.
If you use a sauna, drink water afterward to replace the fluid you sweated out.
Safety note: Long, very hot sessions aimed at heavy sweating can cause dehydration, dizziness and fainting. In one study, healthy adults sweated about 3 pounds of fluid an hour (about 47 ounces) in an infrared sauna set to 149°F. Blood pressure medicines can make you light-headed when you stand up after a sauna.
Talk to a healthcare professional if: you think you were exposed to a toxic substance such as lead or mercury (testing and treatment need a medical visit), or you are pregnant, have heart or kidney disease or low blood pressure, or take blood pressure medicine and plan to use a sauna.
A major review of sweat physiology finds no way for sweat glands to concentrate toxins, and the studies that reported high levels in sweat mostly used collection methods that pick up oil and cells from the skin. Confidence is moderate because the studies are small and use different methods, and none has shown that sweating lowers the amount of a toxin stored in the body.
Your liver, kidneys and gut clear toxins, not your sweat; sweat carries only tiny traces of metals and chemicals, and a sauna does not detox you. A large 2019 review found that sweating plays a minor role in removing waste or toxic substances compared with the kidneys and gut, and that sweat glands do not ramp up removal when you sweat more. Most of the chemical BPA, for example, leaves the body in urine within hours, and the main route out for heavy metals is stool.
Some studies have measured metals, pesticides and plastics chemicals in sweat, sometimes at higher levels than in blood. A 2012 review of 24 such reports suggested sweating deserves study for removing metals in people with high exposure. A later review pointed out that in most of the studies with the highest readings, people scraped sweat off their own skin without supervision, which mixes in skin oil and skin cells and makes sweat levels look higher than they are. In one small study of 12 students, sweat from running on a treadmill held more of several metals than sweat from sitting in a sauna. Detecting a substance in sweat is not the same as lowering the amount stored in the body.
- Baker LB. Physiology of sweat gland function: the roles of sweating and sweat composition in human health. Temperature (Austin). 2019;6(3):211-259. DOI: 10.1080/23328940.2019.1632145. PMID: 31608304. PMCID: PMC6773238
- Sears ME, Kerr KJ, Bray RI. Arsenic, cadmium, lead, and mercury in sweat: a systematic review. Journal of Environmental and Public Health. 2012;2012:184745. DOI: 10.1155/2012/184745. PMID: 22505948. PMCID: PMC3312275
- Kuan WH, Chen YL, Liu CL. Excretion of Ni, Pb, Cu, As, and Hg in sweat under two sweating conditions. International Journal of Environmental Research and Public Health. 2022;19(7):4323. DOI: 10.3390/ijerph19074323. PMID: 35410004. PMCID: PMC8998800
- Jenkins EJ, Killick JA, Grimm SR, Davies SR, Benson JA, Tremblay JC, Stembridge M. Far-infrared sauna exposure at 65°C elevates core temperature. Experimental Physiology. 2026 (online ahead of print). DOI: 10.1113/EP094028. PMID: 42533687. PMCID: PMC13424908
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