How to Clean Garments Made With 37.5 Technology

What if someone told you that some of your favorite clothing items were made from volcanic sand and coconut shells? It sounds crazy, right?

It’s definitely unusual, but the secret ingredients in 37.5® Technology are incredibly useful. These materials, whose incredibly absorbent properties were discovered by Dr. Gregory Haggquist (founder and Chief Technology Officer of 37.5 Technology), are already found in garments from big-name brands like Rossignol, Carhartt, Rab, and about 60 others worldwide.

Volcanic sand and coconut shells are embedded into the fibers in the fabric, and they’re so porous (read: absorbent) that rather than simply wicking away moisture from the body while you’re exercising, your clothing actually moves moisture vapor away from your body. This optimizes thermoregulation, making it easier for your body to stay at its optimum temperature of 37.5 degrees Celsius.

Since clothing containing 37.5 technology contains ingredients that make such a huge difference in your performance, you might think it requires all kinds of special care—dry-clean or hand wash only, don’t dry, that sort of thing. But we’ve got good news! No special care is needed to wash these items. We talked with Alan Lekan, 37.5’s Product Specialist, for tips and tricks on keeping your clothing clean and in tip-top shape.

Shirts, Pants, and Socks

For most items with 37.5 Technology, you can just follow the standard wash care instructions on the item’s label. In fact, washing and heat-drying your 37.5 clothes actually refreshes the active microparticles in the clothing. Washing your clothes removes any odor molecules they’ve trapped during use, including sweat and the ubiquitous smoky campfire smell.

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Because 37.5 Technology is embedded into the fibers themselves, it’s permanent and doesn’t wash out.


Because 37.5 Technology is embedded into the fibers themselves, it’s totally permanent and doesn’t wash out, period. Lots of gimmicky finishes wash out in just a couple of washes, quickly negating any benefit and adding chemicals to the waste stream. You’ll never have to worry about that with 37.5 Technology, in part because of the excellent quality of the brands 37.5 partners with.

In order to test just how durable the 37.5 fibers are, the company collected and checked shirts using the technology. Even shirts that had been worn for five years and washed up to 100 times had the exact same quantity of 37.5 active mineral particles as a brand-new, never-before-worn shirt.

Jackets and Shells

In addition to base layers and fleece, which you’re likely comfortable washing as you would any other garment, you’ll find 37.5 Technology in waterproof-breathable shells and laminates. Of all garments the consumer most fear to launder, it is expensive waterproof-breathable shells.  But fear not, the best thing you can do is wash and dry them to keep them working at maximum performance.

Care of waterproof/breathable rainwear with 37.5 Technology is similar to caring for GORE-TEX® jackets. To maintain repellency performance, it’s best to wash your waterproof shell with powder detergent (as opposed to liquid or pod), on complete or double rinse.

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For most items with 37.5 Technology, you can just follow the standard wash care instructions on the item’s label.


Here’s the part that might surprise you: don’t just hang up that rain jacket to air dry. Contaminants like dirt, smoke particles, and detergent gum up the durable water-repellent (DWR) finish, which reduces surface tension. This allows moisture to get through the DWR and the fabric, so you absolutely need to wash and dry in high heat.

Think of it this way. That waterproof/breathable shell was probably fairly expensive, right? Don’t baby it—your shell can take it! People are a little wary of turning up the heat with their waterproof shells, but that’s exactly what the DWR needs in order to maintain its high surface tension and be fully repellent. If you want to prolong that spendy jacket’s life, the worst thing you can do is avoid washing it. (The second-worst thing would be to wash but not heated dry.)

When it comes to garments that maximize your performance and are super easy to care for, 37.5 staff recommends the Hyde LT Pant by Vertx, one of 37.5’s tactical/sportswear partners. “Don’t let the 35% cotton scare you,” says Lekan. “As the 37.5 fiber (and water-repellent finish) keeps the cotton dry and facilitates moisture pulling away from the skin, so they never feel clammy or hot.” You’ll never want to take them off, but remember: they’ll work better if you wash them occasionally.