Fitness studios and sauna marketers have spent years selling the idea that sweating flushes toxins from your body, but a board-certified dermatologist and the Cleveland Clinic say the liver and kidneys do that job, not your sweat glands.
Dr. Mona Foad, a board-certified dermatologist and founder of MONA Dermatology, laid out the real science of perspiration in a USA TODAY feature published July 1. Sweating matters, she said, but not for the reasons most gym-goers think.
Foad was direct about the primary function of sweat:
"Sweating is a normal and important function of the body. Its primary purpose is to help regulate body temperature and prevent overheating."
That is the core takeaway, and it runs against a marketing narrative that has become almost gospel in wellness culture. Hot yoga studios, infrared saunas, and heated boot camps routinely promise customers they can "sweat out" heavy metals, alcohol, and other impurities. The pitch sounds scientific. It isn't, at least not in the way it's sold.
The Cleveland Clinic identifies three ways sweating benefits the body: it prevents overheating, it protects skin from infection, and it hydrates the skin. Detoxification does not make the list. The clinic states plainly that the liver and kidneys handle that work.
Foad acknowledged where the confusion comes from. Sweat does wash away trace amounts of heavy metals from the skin's surface. One study published in PubMed Central found that exercise was slightly more effective than sitting in a hot environment, such as a sauna, at removing those trace metals. But "trace amounts" is doing a lot of heavy lifting in that sentence. The volume is negligible compared to what the liver and kidneys process every day.
The detox claim is part of a broader pattern in American health culture, where alternative wellness trends increasingly crowd out conventional medicine, often with more marketing than evidence behind them.
Foad put the detox myth in plain terms:
"While people often associate sweating with 'detoxing,' the reality is that sweating is less about removing toxins and more about helping the body maintain a safe internal temperature."
One of the sharpest points Foad made is that people confuse the byproduct with the cause. Sweating during a run doesn't mean the sweat itself is improving your health. The run is.
She spelled it out clearly:
"But the main benefit is not the sweating itself, but rather what is causing the sweating. For example, exercise has many well-established health benefits for the cardiovascular system, muscles, and overall well-being, and sweating is a byproduct of that process."
Saunas and heated fitness classes may help some people relax or improve circulation, Foad said, but sweating alone should not be treated as a scoreboard for how effective a workout was. Someone who barely perspires during a hard session may be getting just as much benefit as the person soaking through a shirt.
That distinction matters because the fitness industry has built entire pricing tiers around the idea that more sweat equals more results. When the underlying science doesn't support the claim, customers are paying for a feeling, not a measurable health outcome. It's the kind of unsubstantiated health claim that thrives when people stop asking for evidence.
Foad also addressed the anxiety some people feel about sweating too much or too little. Several factors influence how much a person perspires: genetics, fitness level, environment, medications, and underlying health conditions. None of those, on their own, signal a problem.
She offered a practical benchmark:
"Some people sweat very little while others sweat quite a bit, and both can be completely normal. What's more important is whether your sweating pattern is typical for you and whether it changes significantly over time."
In other words, the person to compare yourself to is your past self, not the person on the next treadmill. A sudden, unexplained change in sweating patterns is worth a conversation with a doctor. Routine variation is not.
In an era when real public health threats demand serious attention, chasing imaginary toxins through your pores is a distraction.
Another persistent wellness myth holds that antiperspirants are dangerous because they block the body's ability to cool itself. Foad dismissed that claim directly. Antiperspirants work by temporarily reducing sweat production in the area where they're applied, most commonly the underarms. That's a small patch of skin on a body covered in millions of sweat glands.
"The body has millions of sweat glands distributed throughout the skin, so blocking sweat in one small area doesn't prevent the body from cooling itself effectively."
For most people, standard antiperspirants pose no interference with temperature regulation. Foad noted that people who experience excessive sweating may want to explore medical-grade options, though the article did not specify what treatments those might include or what threshold defines "excessive" in clinical terms.
Understanding how the body actually works, rather than how influencers say it works, remains the best defense against wellness misinformation.
The broader lesson here isn't complicated. Sweating keeps you cool, helps your skin, and accompanies the kind of physical activity that genuinely improves health. It does not purge your body of toxins. The organs that do that job, your liver and kidneys, have been doing it long before anyone invented a $40-a-class hot yoga session.
Foad's commentary, backed by Cleveland Clinic guidance and published research, amounts to a straightforward correction of a claim the fitness industry has profited from for years. The science isn't new. The marketing just keeps outrunning it.
When an entire industry builds its sales pitch on a bodily function it doesn't understand, the people paying the bill deserve a straight answer, and the straight answer is that your sweat is doing exactly what it was designed to do, no upsell required.
