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Smartwool Merino Sport 150 Brief

rated 4.5 of 5 stars
photo: Smartwool Merino Sport 150 Brief boxer/brief/bikini

Super comfortable undies, which will help you stay sweet smelling for days, with no chafing.


  • Very comfortable
  • Breathable
  • Odor resistant
  • No chafing
  • Nice snug fit


  • No fly

Yeah, I'm reviewing underwear. Being a big Merino fan, I decided it was time to take the final step towards full commitment, by going right down to the basics. I decided to give these a try.



Fit: The overall fit is good. I'd read a couple of reviews criticizing the extra wide waistband, but in my opinion, it makes them much more stable and keeps them in place better than other briefs I've used. I like a nice supportive fit, and these totally fit the bill. The flat seams never chafe, even after a long day of hiking.

Breathability/moisture control: I have hiked with these in a variety of conditions, from hot Sierra day hikes, to a chilly, damp Cascade multi-day backpack trip. I've never felt either hot or cold from them, but as Goldilocks once said, always "just right."  The 56%/44% Merino, polyester blend, dries out in a hurry, and rinses out nicely. And they are the first briefs I've hiked in that didn't cause any chafing on multi-day trips with daily wear.


Layering: The fabric is a nice non-bulky jersey knit, and your shorts/pants/leggings slide right over them.

Odor Control: I wore these as my only underwear on a five-day trip in Mt Rainier NP this summer, and though the rest of me stank, that area "down there" was remarkably odor free (as far as I could tell).

Durability: After wearing them on every hike I did from mid-spring to now, in a sabbatical summer, when I hiked multiple times a week, they show no visible wear. The merino/polyester blend has held up better than expected.

Nitpick: The lack of a fly for, you know, is kind of a pain. I realize that would mean a trade-off in support. But I think I'd be happier with that available.

Bottom Line: The best undies are the ones you aren't conscious of. These are always comfortable, and I never have to think about them. Highly recommended.

p.s. In the interest of good taste, I am not posting a picture of me wearing them. You'll just have to use your imagination. 


Multi-day backpacking trips, and numerous long day hikes in the Sierra and Cascades, over three seasons in a variety of weather conditions.

Source: bought it new
Price Paid: $20

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Price Current Retail: $12.50-$130.00
Historic Range: $12.50-$130.00
Reviewers Paid: $20.00
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