Best Base Layers (2026): Merino Wool, Synthetic, and More

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There are a lot of base layers out there, including some that are great but not quite great enough to make our top picks. Here are some more options worth considering if none of the above quite fit the bill for you.

Frequently Asked Questions

What Is the Best Base Layer Material?

This will come down to what you're doing and personal preference. The three most familiar options are merino wool, synthetic nylon blends, and silk.

Merino wool: Generally speaking, merino wool excels at keeping you warm, is nicely breathable, and makes an excellent base layer, which is why it's heavily featured in the guide. For durability, go with a blend like Nuyarn.
Synthetic polyester blends: Synthetics have a slight edge in some circumstances, particularly if you're sweating a lot from highly aerobic activity. Synthetics don't hold as much water and consequently dry faster than merino.
Silk: Silk is incredibly soft and does a reasonably job of wicking moisture away from your skin if you're not working too hard. If you're really exerting yourself, silk is easily overwhelmed, but for travel where you might take a long walk or go to an outdoor event in the evening, silk works well.

What Is the Best Base Layer for Cold Weather?

It really depends what you're doing in cold weather and exactly how cold we're talking. I live in northern Wisconsin. Cold to me is anything below 10 degrees Fahrenheit, at which point I reach for two layers of merino wool. In fact, I start most winter hikes wearing both our top-pick lightweight base layer and our heavy-weight base layer.

If you're in the Florida Panhandle (where I've also spent a good bit of time), you might be able to get by with just our top-pick lightweight base layer and a grid fleece or similar jacket for much of the winter.

What Is the Best Base Layer for Extreme Cold?

A fireplace. Just kidding. When you want to head out into extreme cold—say, cross-country skiing your way through the Boundary Waters in January—the best base layer is several base layers. As noted above, I often wear both our top-pick lightweight base layer and our heavy-weight base layer for winter adventures. Remember, though, that cross-country skiing and snowshoeing aren't easy. You're going to get warm pretty quick, and soaked with sweat if your base layer doesn't wick moisture well. For that reason, I often turn to Nuyarn, like the Artilect above. It wicks more effectively and dries faster than pure merino. The Patagonia capilene are also excellent for winter adventures.

Is Merino Wool the Best Base Layer?

It depends what you're doing. Most of the time I think it is, but if you're really exerting yourself, or otherwise sweating a lot, synthetics may wick better, keeping you drier and therefore warmer. That said, I do not like the feel of most synthetics. Aside from testing them for this guide, I almost never wear them.

Nuyarn is a merino wool/synthetic hybrid weave, wherein merino wool is wrapped around a nylon core for warmth, lightness, and extra durability. The idea is to get the temperature regulation benefits of merino, but to add some of the longevity of nylon. In my experience, Nuyarn mostly works. It's our top pick for base layers, though I find it less necessary in more casual garments where I prefer 100 percent wool.

What's the Best Base Layer for Me?

The right base layer for you is going to be the one that keeps you dry by moving your body heat and sweat away from you. Which base layer is best at this depends on what you're doing. If you're actively moving (hiking, climbing, ski touring, etc) look for something thinner that wicks moisture better, like our top pick the Ibex Woolies Pro Tech Crew. When you stop moving and you need more warmth, throw on an extra mid layer or puffer jacket.

If you're going to been spending less time on the move, or are heading into more extreme temps, sweat is often less of an issue and the base layer is less a way to wick sweat and more of an added insulation layer. This is the scenario in which to go with a heavy weight garment like the Smartwool Classic Merino.

What if you do both? Well, then you might need two different base layers. No matter how much I want to have just one thing that does it all, the fact is nothing is that versatility. Warmer base layers like the Smartwool don't breath well enough to use on the less chilly mornings of a summer backpacking trip, where you need something, but not as much as the Smartwool. At the same time the very lightweight merino layers, while great for high-intensity activities, aren't as warm when you're not moving.

If you're like me, and don't have an unlimited budget, you'll also have to factor in price. This is why I recently added the Carhartt's because while I do own the Woolies and the Smartwool Classic tops, if I wear those all the time I'll be replacing them before I know it. The Carhartt synthetic layers stand up better to wear than merino (even, often, merino blends), and cost less. The combination of the three tops is $260, which isn't too bad for a year-round system that can handle everything from summer backpacking to winter snowshoe trips to working on the truck in an unfortunately cold garage.

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