This Is How Sweat-Wicking Clothing Actually Works

When I say that I live an active lifestyle, I do not mean that I hit the gym a couple times a week and throw in some stretching for good measure. What I mean is that I run my dogs on the levee in New Orleans twice a day for an hour each and in between, I teach two hot yoga classes and hit the gym if I have some time to kill. I sweat through my clothes no less than three times a day.

To make sure that I never actually smell like the dirty, sweaty person that I am, I’m constantly changing, usually in my car, often inappropriately flashing strangers in parking lots. My passenger seat is a fetishist’s dream of damp spandex and my laundry situation is a nightmare.

Sweat-wicking clothing seems like an obvious choice for someone like me. The fabric promises to keep you dry and odor free. Win-win, right? Not so fast. For starters, sweat-wicking clothing is definitely more technologically advanced than it is fashion forward, and after digging a bit, I found that the clothes are produced in ways that are environmentally questionable. But if that doesn’t bother you, and you want that so-so-fresh feeling, sweat-wicking athletic clothes do have some science backing them up.

Let's start with the basics: How do moisture-wicking clothes work? What does sweat-wicking even mean? “It’s similar to roots of a tree that move nutrients from the ground to the branches,” said Laura Tempesta, founder of Bravolution (a brand of athleisure) and former product developer at Nike. “Both are examples of “capillary” action—like the capillaries in your body which move blood. Wicking fabric uses capillary action to move moisture.”

Sweat-wicking clothes aim to take the moisture from your skin, disperse it onto the surface of the fabric, and allow it to evaporate into the air, Tempesta said. And the more the moisture disperses, the quicker it will evaporate. Because the sweat evaporates into the air, the clothes are able to dry more quickly than fabrics like cotton that absorb moisture.

If you’ve ever been stuck in sweaty clothes after a workout, you know how uncomfortable it can be. But there are other factors that explain why some athletes favor clothing that promises to soak up sweat. In order to perform at their peak, athletes must be able to maintain and regulate their body temperature internally. Cold, wet clothes can be a hindrance.

“Moisture-wicking fabric is a much better choice for professional athletes,” says Nikola Djordjevic, a Belgrade-based physician who works with pro athletes, “According to one NCBI study, athletes who wore moisture-wicking fabric were able to preserve their bodies’ temperature, especially in the high heat. This was achieved thanks to better ventilation and evaporation during intense training.”

Djordjevic went on to explain that it isn’t just the moisture factor that can impede performance. It’s the weight of the fabric, too. “Moisture-wicking fabric is made of high-quality polyester which keeps the sweat away from the body. This makes the clothes much lighter and more comfortable, especially during long training.”

For most of us, though, the subtle performance enhancement that sweat-wicking clothes offer won’t make much of a difference. “Sweat is very important because it helps regulate body temperature and keeps us from overheating,” said Heather Summe, a dermatologist and assistant professor of dermatology at Hofstra’s School of Medicine in New York. “When we wear fabric that readily absorbs and retains this moisture, it not only makes it more difficult for our bodies to regulate temperature but it can lead to maceration, or breakdown, of the skin.” She told me that these articles of clothing can also encourage secondary overgrowth of yeast and bacteria.

Everyone’s skin is different, though. Some people simply glow when they work out while others sweat buckets of body juice (“up to three liters of sweat in an hour,” Summe said). So weigh the risks and potential benefits of sweat-wicking clothing and do what you will with them. If you do sweat profusely, either way, you'll want to get the hell out of your gym clothes ASAP when you're done working out.

Hanging around in your hot, wet Lulus for too long can lead to what’s known in some circles, as sports vagina, which is basically discomfort or irritation of the vulval zone and buttocks. Penis-havers are equally, if not more vulnerable to sweat-related unpleasantry. “The genital area, especially in men, is a common place to get various kinds of rashes. Genital skin is very thin and sensitive and there is a lot of skin to skin contact.” Summe said.

For all genders, wearing overly moist fabric can lead to a higher chance of the development of intertrigo, which is inflammation caused by skin-on-skin friction. “Keeping this area clean and dry is important but over-cleansing should also be avoided. I also tell men with athlete’s foot to put their socks on before their underwear to avoid spreading fungus from their feet to their groin.”

That being said, I soaked through a bunch of sweat-wicking apparel that athletic companies graciously sent me for free, and there were a few that stood out in terms of design and functionality. The Adidas Supernova Run Cru Sweatshirt is a dope, light, pullover that I will be wearing on the regs. Asics Metarun SS Top is delightfully techno-licious, very last days of rave in a way that I love. And if you want a basic tee, Brooks’s Stealth Short Sleeve Tee is solid and versatile.

These aren't the only options if you want to wick sweat, though, especially if you're concerned about the environmental costs to techie fabrics in general. “‘Moisture-wicking’ and ‘sweat-wicking’ are marketing terms meant to boost the reputation of these products and make them sound scientifically proven and of superior performance, although it's a poor characteristic of the product,” says Andrea Plell, an ethical fashion consultant and co-founder of Sustainable Fashion Alliance, which helps apparel companies meet environmental goals, “When these fabrics are washed, they shed micro-plastics that subsequently make their way to our waterways and into the guts of marine life.”

If sweaty clothes are gross for me and sweat-wicking clothes are gross for the planet, what’s an active human like me with a conscience to do? The same thing that humans have done since humans started weaving: Try wool. In the summer? In New Orleans? Hear me out.

I found Merino wool to be a great more environmentally conscious, alternative to high-tech fabrics. “Merino fiber is able to absorb up to a third of its weight in moisture while still feeling comfortable and dry,” said Dan Demsky, co-founder of Unbound Merino—a brand of, you guessed it, Merino wool-based attire. He tells me that the type of fibers in the material make it naturally sweat-wicking.

“Wool can absorb a bit of water into the fiber itself in addition to wicking moisture through small pores within the fabric,” said Fayne Frey, a New York-based dermatologist. Still, she said she doesn’t know of any standardized test where one can compare the “moisture-wicking” ability of one material to another.”

When I first considered wool, I was scared I'd sweat to death. But I tried a lightweight wool tee with a loose cut and it allowed air to circulate around my body. It did get dampened with sweat, but didn't stick to my skin the way cotton does. It feels kind of like having armpit hair—as in it gets sweaty, but that sweat cools me.

I've washed one of them once and the other zero times and you know what they both smell like? Yoga. In the end, your choice in athletic attire is kind of like attending a work party—have fun but just get out before things get weird.