Best Base Layers of 2025

In the cold, layers matter — and it all starts with the base layer, an important and versatile piece of clothing that can help you master the oh-so-fine balance of staying warm but not too warm when you run in the cold. The best base layers will help you stay warm, dry, and comfortable for your whole run, and depending on the temperature and thickness of the layers, you can wear them underneath a jacket or by themselves.

There is no shortage of options and differences among base layers — they range in size, thickness, materials, and price — so choosing the right one can be a challenge. That’s why we created this guide: to help you find the best base layer depending on your needs and preferences. Our experienced team of testers ran in a variety of base layers everywhere, from the San Juan Mountains of Colorado to the high deserts of southern Utah to the humid air of North Carolina, to see which ones performed the best. We tested various materials, from merino wool to synthetic fibers, and considered different price points to provide a comprehensive look at the best base layers for men to keep you running strong in cold weather.

Ultimately, we chose the Montane Dart Zip Neck T-Shirt and the Patagonia Capilene Midweight Crewneck as our favorites. We also loved the Tracksmith Harrier Tee as a short-sleeve option, and we picked the REI Co-op Midweight Long-Sleeve Base Layer Top as a solid budget choice.

For more background information about different types of base layers and how we arrived at our favorites, see our buying advice, testing methodology, and frequently asked questions below the picks.

Best Base Layers

• Best Base Layer: Montane Dart Zip Neck T-Shirt
• Best Base Layer — Runner-Up: Patagonia Capilene Midweight Crewneck
• Best Budget Base Layer: REI Co-op Midweight Long-Sleeve Base Layer Top
• Best Short Sleeve Base Layer: Tracksmith Harrier Tee
• Best of the Rest Base Layers: Cotopaxi Debajo Seamless Baselayer Crew, Brooks Notch Thermal Hoodie 2.0, Tracksmith Brighton Base Layer

Best Base Layer: Montane Dart Zip Neck T-Shirt ($50)

Pros:

• Extremely comfortable
• Great moisture-wicking abilities
• Seems designed for runners

Cons:

• Polyester is not as warm as other materials

The Montane Dart Zip Neck T-Shirt is an excellent option for any high-output cold-weather pursuit and tops our list as the best base layer for running for a variety of reasons. First, the fit. The shirt’s quarter-zip, collar, and form-fitting cut help make this shirt snug and practical. We found the recycled polyester fabric to be supremely comfortable, and even on warmer days when we were sweating more, we had no problem with chafing.

Montane treats the shirt with Polygiene, a proprietary odor-control formula we found effective. We got multiple days and dozens of miles between washes with little to no stink. We were also impressed by this base layer’s ability to wick moisture and offload heat, and it quickly became the layer we grabbed for speed or tempo work when extra moisture control was necessary. Finally, at $50, this layer is tremendous value.

We also featured the short-sleeve version of this shirt in our best running gear for hot weather and best running shirts for men guides.

Material: 100% recycled polyester | Fit: Skin-tight

Shop the Men's Montane Dart Zip Neck T-ShirtShop the Women's Montane Dart Zip Neck T-Shirt

Best Base Layer — Runner-Up: Patagonia Capilene Midweight Crewneck ($89)

Pros:

• Excellent quality for the price
• Comfortable

Cons:

• Not as warm in icy conditions
• Odor control is not as strong as that of other options

The Patagonia Capilene Midweight Crewneck is a classic base layer that’s been around for a long time, and there’s a good chance that anyone who’s run through a winter or two has one in their closet. Its popularity makes sense: Patagonia’s proprietary Capilene material, made from 100% recycled polyester, is incredibly comfortable and lasts longer than many other base layers created from other materials. This layer is made with hollow-core yarns and has a diamond-grid pattern inside to trap warmth and wick moisture, though it’s not the warmest option when temperatures really dip. It has elastic thumb loops for extra hand coverage and is supremely breathable like all of Patagonia’s Capilene products.

The shirt’s HeiQ Mint odor control helps keep some of the smell at bay by reducing bacteria growth — and, therefore, smell — but the stink control doesn’t compare to wool products. Patagonia manufactures this base layer in a Fair Trade Certified factory and donates 1% of its sales each year to grassroots environmental nonprofits. It’s a shirt you can feel good about owning.

Material: 100% recycled polyester | Fit: Slim

Shop the Patagonia Men's Capilene Midweight CrewneckShop the Patagonia Women's Capilene Midweight Crewneck

Best Budget Base Layer: REI Co-op Midweight Long-Sleeve Base Layer Top ($55)

Pros:

• Great price for a solid product

Cons:

• Less breathable than other options
• Boxy fit

The REI Co-op Midweight Long-Sleeve Base Layer Top is an excellent value, mimicking the feel of Patagonia Capilene Midweight Crewneck for a lower cost. Made from a blend of 92% recycled polyester and 8% spandex in a Fair Trade Certified Factory, this shirt is comfortable, breathable, and versatile. Lightweight and with a UPF 50 rating, it could double as a sun shirt. It also has thumb holes to help hold the sleeves in place and provide extra coverage for your hands.

We found this shirt’s fit to be more boxy than other options, and it’s one of the rare base layers that runs slightly big. We’d still recommend you go with your standard size; just know it’s not as form-fitting as traditional base layers.

If you’re searching for the best value, this shirt is hard to beat.

Material: 92% recycled polyester, 8% spandex| Fit: Loose

Shop the Men's REI Co-op Midweight Long-Sleeve Base LayerShop the Women's REI Co-op Midweight Long-Sleeve Base Layer

Best Short Sleeve Base Layer: Tracksmith Harrier Tee ($90)

Pros:

• Versatile
• Soft and odor-resistant

Cons:

• Costly

The Tracksmith Harrier Tee is a classic running shirt with properties that make it a great base layer. It’s a staple for all types of weather, from hot summer runs to crisp fall days, which is why you’ll also find it in our best running shirts for men guide. Its loose and comfortable fit makes it ideal to wear under a long-sleeve shirt or jacket during cold winter runs.

Made from a blend of 48% merino wool and 52% nylon, this shirt is incredibly soft and lightweight. It is loose enough to provide ample range of movement and airflow but snug enough to be a warm layer. It features 37.5 Technology, a fabric created by a Colorado-based company founded by a Ph.D. chemist that designs materials to improve temperature regulation by speeding the transfer and evaporation of moisture from your skin. Pair that with the merino wool, and the result is an ultra-comfortable, versatile, odor-resistant, and high-tech shirt.

As with most Tracksmith products, the biggest downside is its cost. At $90, this short-sleeve shirt costs more than most long-sleeve layers in this guide. But in addition to all of its other qualities, the Harrier Tee is also durable, providing our testers with a high-quality top for many runs across many seasons, so we believe it’s worth the investment.

Material: 48% merino wool, 39% 37.5 Technology nylon, 13% nylon| Fit: Relaxed

Shop the Men's Tracksmith Harrier TeeShop the Women's Tracksmith Harrier Tee

Best of the Rest Base Layers for Men: Cotopaxi Debajo Seamless Baselayer Crew ($80)

Pros:

• Comfortable with a great fit

Cons:

• Heavier material
• Picks up odor quickly

While Cotopaxi is best known for its multicolored backpacks and puffy jackets, the Cotopaxi Debajo Seamless Baselayer Crew demonstrates the brand’s range. This layer is designed and marketed for snowy pursuits, but we found it to be a strong option for cold-weather runs as well.

This shirt is comfortable right out of the package, and the mix of recycled nylon and polyester with added spandex gives it a snug, true-to-size fit. Because Cotopaxi designed it for lower-output activities than running, this top feels slightly thicker than the other base layers we tested. As a single, stand-alone layer, it kept us plenty warm in temperatures down to 40 degrees Fahrenheit, and it would be a perfectly viable layer at even colder temperatures.

Despite containing a Polygiene anti-odor finish, this layer, like many other synthetic ones, picks up odor quickly. We found it becoming smelly after just two uses without a wash. Luckily, though, it’s easy to wash, and that was the only knock on an otherwise snug, comfortable base layer.

Material: 66% recycled nylon, 27% recycled polyester, 7% spandex | Fit: Snug

Shop the Men's Cotopaxi Debajo Seamless Baselayer CrewShop the Women's Cotopaxi Debajo Seamless Baselayer Crew

Best of the Rest Base Layers for Men: Brooks Notch Thermal Hoodie 2.0 ($98)

Pros:

• Warm but easy to ventilate
• Versatile
• Watch window is a unique feature

Cons:

• Not made for moderate temperatures

We feel that calling the Brooks Notch Thermal Hoodie 2.0 a base layer doesn’t fully capture its versatility as you could easily wear it on its own in cold temperatures, but paired with a windbreaker over top or a thinner layer underneath, this shirt can keep you quite cozy. In fact, one of our primary testers for this shirt, who lives in the San Juan Mountains in Colorado, counts it among his favorite shirts for running in cold winters.

This layer, made with a soft, textured fabric, is highly insulated but also wicks moisture well, and even in warmer temperatures, never felt saturated with sweat. Its antimicrobial finish helps with odor resistance, too. Paired with another layer, it can keep you warm in temperatures as low as 10 degrees Fahrenheit, and when the wind picks up or the sun dips behind the mountains, pulling up the hood can provide an extra five to 10 degrees of apparent warmth. Perhaps its most unique feature, though, is a watch window that allows you to check your pace without having to roll up your sleeves and expose your arms to the elements. It’s a shirt designed for the cold.

Conditions on the trails can change, of course, so if the temperature suddenly rises, you can rely on the sizable half zip to provide more ventilation. You can also roll away the hood. These modifications can keep you comfortable in temperatures as high as 45 degrees. It’s this versatility that led us to also feature this shirt as the best cold-weather option in our best running shirts for men guide.

Material: 91% polyester, 9% spandex | Fit: Semi-fitted

Shop the Men's Brooks Notch Thermal Hoodie 2.0Shop the Women's Brooks Notch Thermal Hoodie 2.0

Best of the Rest Base Layers for Men: Tracksmith Brighton Base Layer ($100)

Pros:

• Soft and odor-resistant
• Versatile

Cons:

• Expensive

Like the Harrier Tee, the Tracksmith Brighton Base Layer is one of the brand’s classic shirts — again, for good reason. A lightweight merino top, this layer is soft, versatile, and odor-resistant — checking all the boxes for what you’d want from a base layer.

Made from a merino wool blend, this shirt embodies the hallmarks of the material: comfort and odor resistance. One of our primary testers ran in it for weeks without washing, and it still didn’t smell. Another tester, a runner and ski guide, called this shirt one of her go-to’s for shoulder-season running and touring. While Tracksmith designed it to go underneath a jacket or mid-layer, you could wear it on its own in warmer temperatures. Its seamless construction and subtle diagonal stripe make it, like many Tracksmith products, among the more stylish pieces of running apparel you’ll find.

You can read more about the Brighton Base Layer in our Tracksmith Cold Weather Apparel review.

Material: 52% merino wool, 28% nylon, 20% polyester | Fit: True to size

Shop the Men's Tracksmith Brighton Base LayerShop the Women's Tracksmith Brighton Base Layer

Comparing the Best Base Layers for Running

BASE LAYER	PRICE	MATERIALS
Montane Dart Zip Neck T-Shirt	$50	Recycled polyester
Patagonia Capilene Midweight Crew	$89	Recycled polyester
REI Co-op Midweight Long-Sleeve Base Layer Top	$55	Recycled polyester, spandex
Tracksmith Harrier Tee	$90	Merino wool, nylon
Cotopaxi Debajo Seamless Baselayer Crew	$80	Recycled nylon, recycled polyester, spandex
Brooks Notch Thermal Hoodie 2.0	$98	Polyester, spandex
Tracksmith Brighton Base Layer	$100	Merino wool, nylon, polyester

Buying Advice: How to Choose Base Layers for Men

When buying a base layer, consider several factors: What’s the climate like where you’ll be putting in the bulk of your miles? Will you primarily wear the layer underneath a jacket or on its own? What type of material and fit do you prefer?

We’ve outlined several considerations below to help you sift through all the different options.

Fit

Many base layers will be form-fitting, so you can easily add additional layers. Form-fitting options like the Montane Dart Zip Neck T-Shirt and the Tracksmith Brighton Base Layer are great for wearing under other insulating layers or jackets. Others fit more casually, like the REI Co-op Midweight Long-Sleeve Base Layer Top and the Brooks Notch Thermal Hoodie 2.0. Under additional layers, these looser shirts run the risk of bunching, but they can also serve a double purpose as a stand-alone shirt for either trail or casual use.

Weight

Base layer materials have varying thicknesses, each designed for a different temperature range. As the material gets thicker, the weight of a layer increases, so it’s a factor worth considering, especially if you take off the shirt during a run and have to carry it in your pack. Lightweight base layers, like the Patagonia Capilene Midweight Crew and Tracksmith Brighton Base Layer, are great for chilly but not cold temperatures. The Brooks Notch Thermal Hoodie 2.0, meanwhile, is heavier but warmer.

Material

For many, the material of a base layer is the primary consideration. Some people are committed to wool, while others love the feel of synthetic fabrics. Wools are sometimes coarser than other fabrics, though modern merino wool has all but eliminated the scratchiness historically associated with the fiber. Synthetics tend to feel silkier but are often not as warm or odor-resistant. And then there’s spandex, another material commonly used in base layers to make them form-fitting and help them keep their shape. Often, the best material is a mix, like that of the Tracksmith Harrier Tee, which is made from a blend of merino wool and nylon and takes advantage of the beneficial properties of each of the different materials.

UPF Rating

Besides just keeping you warm, long sleeves can protect your skin from the sun. A base layer like the REI Co-op Midweight Long-Sleeve Base Layer Top with a UPF 50 rating provides a higher level of protection than a top made of wool, which is a more porous material. If you’re looking for shirts that are designed to protect against the sun, you can check out our best sunshirts for running guide.

Breathability

Wicking moisture from your skin to keep you dry is one of the most important functions of a quality base layer. They are, after all, supposed to keep you warm and dry. The Patagonia Capilene Midweight Crew has been a leader in breathability for years, followed closely by the Montane Dart Zip Neck T-Shirt, and the merino-wool blend with 37.5 Technology nylon in the Tracksmith Harrier Tee makes it supremely breathable.

Odor Prevention

You still sweat, even when it’s cold, so picking an odor-resistant base layer is important. Wool or wool-blend products, like the Tracksmith Brighton Base Layer, are known for staying odor-free for multiple uses without washing. Synthetic materials are prone to picking up odors, but companies have started using newer fabric technologies — like the Polygiene odor control formula in the Montane Dart Zip Neck T-Shirt — to minimize the growth of bacteria, the root cause of odors. If odor resistance is your primary consideration, go with something made of natural fibers.

Durability

The best base layers can — and should — last a long time if cared for properly. Base layers made of synthetic materials, like the Patagonia Capilene Midweight Crew, are often more durable than those made of natural fibers, including wool, though there are certainly steps you can take to extend wool products’ life spans, including air drying them. We didn’t experience any durability issues with any of the products reviewed in this guide.

Warmth

Your specific running climate is the clear factor to consider when determining how warm you want your base layer to be. Lightweight layers like the REI Co-op Midweight Long-Sleeve Base Layer Top could be worn solo in cool weather or under a jacket in cold temperatures, while weightier tops like the Cotopaxi Debajo Seamless Baselayer Crew and Brooks Notch Thermal Hoodie 2.0 will provide more warmth for cold days on the trail.

Styles

Base layers come in several different styles. Most have long sleeves, but you could also wear a solid short-sleeve option like the Tracksmith Harrier Tee. There are also options with quarter zips, like the Montane Dart Zip Neck T-Shirt, and others with longer zippers, like the Brooks Notch Thermal Hoodie 2.0, to provide extra ventilation. The latter option also comes with a roll-away hood. Some base layers, like the Cotopaxi Debajo Seamless Baselayer Crew and the Tracksmith Brighton Base Layer, are also versatile and stylish enough to wear outside of running.

Sustainability

Purchasing products they can feel good about is a growing consideration among many runners. Before buying a product, you might consider the company’s environmental record and how they compensate and treat their producers and plant workers. With products like the Patagonia Capilene Midweight Crew, which features 100% recycled polyester in a Fair Trade Certified factory, Patagonia was one of the first companies to focus on the environmental and ethical impacts of making outdoor apparel. Since 1985, it has donated 1% of its sales to environmental causes. The REI Co-op Midweight Long-Sleeve Base Layer Top also includes recycled materials in a Fair Trade Certified factory, and Cotopaxi is likewise known for its sustainability-forward mission.

Why You Should Trust Us

To choose the best base layers for different running conditions, we ran in lightweight and midweight options in as many conditions as possible. From the Linville Gorge near Boone, North Carolina, to the high peaks of the San Juan mountains of Colorado, multiple testers rated base layers on their comfort, warmth, breathability, fit, and style. Our testing included base layers made of natural wool and synthetic materials, and we noted which products we could wear multiple times without stink and which had to go to the washing machine after every run. We wore the base layers as stand-alone layers and under additional insulation during our cold-weather runs to get a good sense of the breathability of each material. Each base layer underwent several wash cycles to test its durability and comfort.

We continue to test the products included in this guide to uncover any durability concerns and add new products into our testing rotations as they become available. We keep this guide updated with products that stand out from others on the market, and we can trust them to keep us warm in different weather conditions.

Frequently Asked Questions About Base Layers

What makes merino wool a good base layer material?

Merino wool, a seemingly magic fiber, is found in many of the best base layers, and for good reason. The naturally porous fiber moves moisture from the skin to the outer part of the garment while it’s still in vapor form. This means moisture won’t turn into droplets and soak a base layer. By staying dry, wool remains comfortable and reduces the chance of chafing. Wool is also an excellent insulator, and merino wool comes from sheep that live in cold, harsh environments, where it has evolved to keep them warm. Unlike many other materials, wool retains its insulating properties even when wet.

Wool is also known for its anti-odor properties. You can wear most layers multiple times without picking up any stinch. Fastpackers out on multi-day trips or runners who don’t want to wash layers after every run love stink-free wool. While it definitely doesn’t have the silky feel of many synthetic materials, merino wool is much less scratchy than the old wool sweaters of yesteryear. You can find out more about other wool products we love in our best wool running apparel guide.

Some base layers, though none that made it into this guide, are 100% wool. Many others, like the Tracksmith Brighton Base Layer and Tracksmith Harrier Tee, use wool blended with a synthetic fiber for increased durability.

What is the best type of base layer for running?

The best base layer for running depends on many factors, including a runner’s preferences and geographical location. The two main things to consider are the material the base layer includes and the thickness of the material. Base layers generally include wool, synthetic materials, or a combination of the two. They come in light-, mid-, and heavy-weight thicknesses, though for this guide, we mainly tested light- and mid-weight layers due to the high heat output of running. After carefully testing and analyzing many base layer options, the Montane Dart Zip Neck T-Shirt stood out for its warmth, breathability, and fit.

You’ll want to choose the lightest base layer that works for most of your running conditions. You can always add layers on top of a light base layer, but if you get one that’s too thick, there won’t be much you can do if you start overheating. And since the ultimate goal of a base layer is to move moisture from your skin to the outside air, you don’t want something too thick. Breathability is key. Many experts say it’s essential to dress for 15 to 20 degrees Fahrenheit warmer than the thermometer is reading because once you get moving, that’s how it will feel.

What are the best types of base layers for extreme cold?

A base layer shouldn’t be your sole layer when temperatures really drop. Instead, it is a piece of your layering system, designed to move moisture away from your skin so that it can evaporate, keeping you from getting wet and cold. Base layers are the foundation for running in cold temperatures, and layering on top of them will ultimately keep you warm.

The best base layers for layering are form-fitting, so they don’t bunch up under whatever other layers you wear. While most base layers are highly breathable, wool is exceptional at moving moisture from the skin to the outside of the shirt so that it can evaporate. A midweight base layer, like the Patagonia Capilene Midweight Crew, whether worn solo or layered with a jacket, can work for many situations. You can learn more about running in cold weather at our best cold-weather running gear guide.

Are there warmth ratings for base layers?

While no official ratings for base layers exist, most are light, medium, or heavy. Lightweight layers, like the Tracksmith Brighton Base Layer, are great for shoulder-season chilly runs as a stand-alone layer. The breathability of base layers makes them ideal for wearing under jackets and other insulating layers. Mid-weight layers like the Patagonia Capilene Midweight Crew are good for using alone on colder runs and underneath more layers when things get really cold. Heavy-weight base layers are generally only good for the most frigid conditions and lower effort levels since they tend to be very warm and don’t breathe as well as a lighter layer. The Montane Dart Zip Neck T-Shirt is a great base layer set that will suit runners in many colder climates.

Call for Comments

• What’s your favorite base layer?
• What’s your layering strategy for running in cold weather?

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