Saxx Sub-Zero Longjohns Review

Saxx Sub-Zero Longjohns

My first exposure to Saxx Underwear and their “package pouch” was for my review of the Blacksheep men’s long underwear. Keeping your legs warm can alleviate a lot of discomfort when you’re outdoors, and their merino-wool long underwear performed pretty well. The company has an even heartier model for cold temperatures, though, so the Saxx Sub-Zero Longjohns were my next review target.

The Sub-Zero longjohns have two real value propositions, one of which is shared with the Blacksheep. That common feature is a front pouch set apart by two vertical flaps of mesh material to keep your “package” from chafing against your thighs. As I said in my review of the Blacksheep long underwear, those two simple mesh flaps do a great job keeping friction at bay. The resulting comfort is identical with these Saxx Sub-Zero Longjohns.

During several snowshoeing trips around Mt. Hood National Forest, I found the longjohns’ other value proposition to also hold true. The Sub-Zeroes are indeed warmer than the merino-wool Blacksheep. Part of that is due to their thickness, which is about two times greater than the Blacksheep, but it’s also because they have a wind-blocking front material that helps cut any breeze that tries to blast through the front of your pants. The wind-blocking is only up front, and I did notice a temperature change when the mountain gusts came from behind. But presuming you’re hiking or snowshoeing into the wind, you’ll be fine.

As warming as that wind-block material is, it does make the front pouch feel like crinkly wax paper. I didn’t notice any scraping or discomfort while I was active, but when it was time to answer mother nature’s call, the stiffness of that front flap was a bit difficult to navigate.

Speaking of material, it’s worth pointing out that the Saxx Sub-Zero Longjohns aren’t 95% merino wool like the Blacksheep. Instead, they’re 85% polyester and 15% spandex, which makes them feel a lot more like athletic pants than a traditional long-underwear baselayer. They’re tighter and have less give when you’re putting them on, but the flip side is that they don’t suffer from the same sagging or deformation that the merino long underwear do. The polyester/spandex mix also means the Sub-Zeroes don’t have the same stink-killing qualities as merino, which if you’re active for a few hours is indeed noticeable.

Normally I’d say their increased warmth overrode such complaints. After all, my primary goal is keeping warm outside. But the physical cut of the Saxx Sub-Zero Longjohns also differs from the Blacksheep, causing the Sub-Zeroes to slip down in back whenever I bent over. The cut of the legs also restricted my hip flexibility unless I continually pulled them back up toward my package. This poor fit was the proverbial straw that broke the camel’s back for me.

Designed for colder temperatures, the Saxx Sub-Zero Longjohns are indeed warmer than their merino wool counterparts. They offer the same anti-chafing comfort. But they aren’t nearly as comfortable. On a couple of sub-freezing outings I was glad I had them on, but when the temperature was even slightly above freezing I gladly sacrificed some of that warmth for a better fit and went back to the Blacksheep. For thicker material and greater warmth, I think I’ll need to explore some heavier-weight wool longjohns, because these Sub-Zeroes aren’t my long-term solution.

The Saxx Sub-Zero Longjohns were provided for review. All opinions and words are my own and honest, and the article contains no affiliate links.

Saxx Sub-Zero Longjohns

Saxx Sub-Zero Longjohns


8.5 /10


9.0 /10


6.0 /10


7.5 /10


  • Anti-chafing flaps work great
  • Wind-blocking keeps the breeze at bay
  • Super soft inside and out


  • Odd cut causes plumber's crack and poor hip flexibility
  • No smell resistance like their merino-wool kin

Jonas Allen

Jonas spent 17 years covering travel, technology and entertainment for regional and international media. He now writes about gear, clothes and tips to stay warm. He hopes his lessons will help other people who get cold (re)discover the great outdoors.

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