It’s pretty much impossible to shop for outdoor clothing without running into the phrase “moisture wicking.” Brands are forever telling you their apparel is made of this moisture-wicking stuff, so it must be important. But what exactly do they mean?
A moisture-wicking fabric has two jobs: one is quickly moving (wicking) sweat to the fabric’s outer surface and the other is drying rapidly so that your sweat doesn’t saturate the fabric. The result is that you’re more comfortable because your body can regulate its temperature efficiently and the fabric touching your skin has a dry, nonsticky feel.
How Moisture-Wicking Fabrics Work
Moisture wicking relies on “capillary action,” which is the movement of a liquid (sweat in this case) through tiny spaces within a fabric due to the molecular forces between the liquid and the fabric’s internal surfaces. Brands refine this process by carefully engineering the structure of the yarns within their fabrics, and by applying a variety of treatments to surfaces within that structure.
Don’t sweat the science, though, just look for the magic phrase “moisture wicking.” And don’t get caught up in any testing claims because brands use a variety of tests to measure moisture wicking and there’s no standard test you can use for comparison.
Which Fabrics Are Moisture-Wicking?
- Most moisture-wicking fabrics are synthetics: When moisture gets absorbed into a fabric’s yarns, it’s trapped there instead of moving through the fabric. That’s a recipe for poor moisture-wicking performance. Synthetic fabrics are “hydrophobic,” which means they resist the penetration of water. That’s why you see a lot of synthetic fabrics, like polyester or nylon, excel at moisture wicking.
- Wool is also considered moisture-wicking: Wool is a slightly different animal. It actually absorbs a small amount of liquid into the core of its fibers, but it also wicks moisture out through small openings within the fabric. The result is that the surface of wool yarns remains dry to the touch.
- Cotton is the “anti-moisture-wicking” fabric: The classic example of a nonwicking fabric is cotton, which gets completely saturated with sweat and then takes forever to dry. Initially, it makes you feel hot and sticky; ultimately, it leaves you feeling cold and clammy. You can find cotton fabrics that have been specially treated to make them moisture wicking, but their performance lags behind synthetics and wool.
Why Choose Moisture-Wicking Fabric?
When you’re breaking a good sweat, that sweat evaporates and produces a cooling effect. After skin temperature cools to a comfortable level, your body stops sweating. It’s a super-efficient process, and one that an effective moisture-wicking fabric will complement.
Generally, you want moisture-wicking fabric on any apparel that touches your skin, like a long underwear base layer. You also want it on clothes you plan to wear while you’re doing aerobic (sweat-producing) activities like hiking or running. For more information about how to choose these types of clothing, look at How to Choose Base Layers or What to Wear Running.
How to Care for Moisture-Wicking Clothing
The washing instructions for most moisture-wicking garments tell you that fabric softener—in liquid or dryer-sheet form—is a no-no. Fabric softeners lay down a waxy residue that interferes with a fabric’s carefully engineered finish. When you use fabric softener, you’re basically trading moisture-wicking performance for a slightly softer feel.