Science, Tech, Math › Science The Chemical Composition of Human Sweat The composition of sweat depends on several factors Share Flipboard Email Print Scott Kleinman/The Image Bank/Getty Images Science Chemistry Molecules Basics Chemical Laws Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated September 22, 2019 As you might imagine, human perspiration is mainly water, but have you ever wondered just what else is in sweat? Here's a look at the process of sweating, the chemical composition of perspiration, and the factors that affect it. Why Do People Sweat? The main reason people perspire is that the evaporation of water can cool our bodies. That's the reason it makes sense that the main component of perspiration is water. However, perspiration also plays a role in the excretion of toxins and waste products. Sweat is chemically similar to plasma, but certain components are selectively retained or excreted. General Composition of Perspiration Perspiration consists of water, minerals, lactate, and urea. On average, the mineral composition is: Sodium (0.9 gram/liter)Potassium (0.2 g/l)Calcium (0.015 g/l)Magnesium (0.0013 g/l) Trace metals that the body excretes in sweat include: Zinc (0.4 milligrams/liter)Copper (0.3–0.8 mg/l)Iron (1 mg/l)Chromium (0.1 mg/l)Nickel (0.05 mg/l)Lead (0.05 mg/l) Variations in Perspiration Chemical Composition The chemical composition of perspiration varies between individuals. It also depends on what individuals have been eating and drinking, the reason why they're sweating (for example, exercise or fever), how long they have been perspiring, as well as several other factors. Sources Montain, S. J., et al. “Sweat mineral-element responses during 7 h of exercise-heat stress.” International, U.S. National Library of Medicine. International Journal of Sport Nutrition and Exercise Metabolism. December 17, 2007.