sweat week

I Can Sweat Buckets and This (Backpacker-Tested) Sunscreen Won’t Run

Photo-Illustration: Retailer/Getty

I live at a high elevation and spend a lot of time outdoors in the summer. Most of my activities are in the blazing sun, whether I’m backpacking along open ridgelines or kayaking on local rivers. I’ve worn plenty of sunscreens, both chemical and mineral, from ubiquitous brands like Coppertone and Neutrogena, as well as outdoor-specific ones like ThinkSport. While they’ve done the job, I’ve watched some of those sunscreens slough off during sweaty hikes. Others, meanwhile, seem to clog my skin, creating a sticky layer that makes it harder for my body’s natural cooling system to do its job.

Avid backpackers like myself know Sawyer for its reliable water filters that are ubiquitous on trails because they weigh just a few ounces and easily screw onto water bottles. Sawyer also makes highly effective insect repellents — one of which, for mosquitos, may be familiar to Strategist readers. Contributor Maureen O’Connor wrote that its “less greasy” formula lets her “skin breathe more easily” — which is exactly how I feel about the brand’s Stay-Put Sunscreen, a product I started using about a year ago and have since turned many in my backpacking crew on to because of how well it works in the sweatiest of situations — from all-day hikes, to kayak outings, to full days working outdoors.

For example, I was recently in New Hampshire visiting family. While the temperature was similar to that of where I live in Montana, the humidity of the Northeast flattened me. Within the first two miles of a peak-bagging trip, I was drenched in sweat — something I’m not used to in the dry mountain West. Despite being sweatier than I’ve been in years, the sunscreen not only allowed me to sweat through its protective layer, but also stayed put.

This, I suspect, has a lot to do with the proprietary “breathable matrix formula” of the sunscreen — which is chemical, not mineral, so it soaks into skin and absorbs UV rays instead of sitting on top of skin and reflecting them. Based on my experience, the formula allows sweat to pass through without causing the sunscreen’s protective layer to break. It never blocks me from sweating, an issue I’ve run into with other sunscreens. This is important, especially during activities like backpacking in high temperatures and humidity, because releasing sweat helps the body cool.

Of course, like any sunscreen, just because this one lets sweat pass through without making it runny doesn’t mean I don’t reapply. You should always reapply. In my experience, even when you do, a supply will last. (I am actually still making my way through a quart-size jug of the stuff the brand sent me last year.) Its thinner consistency makes applying layer over layer feel less noticeable, though, as does how it easily glides onto skin. I stick to using it on my body — the combination skin on my face requires a face-specific sunscreen — and because it’s chemical, it may be less ideal for anyone with super-sensitive skin. Another plus for Sawyer fans: The brand says the sunscreen is just as effective when used with its picaridin or DEET-based insect repellents.

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I Can Sweat Loads and This Hiker-Tested Sunscreen Won’t Run