10 Best Mens Thermal Shirts 2026 in the United States

The Merino.tech Merino Wool Base Layer is a well-crafted thermal shirt made from 100% superfine Merino wool, known for its softness and comfort without the itchiness common in wool products. It comes in different weights (lightweight, midweight, heavyweight), with the midweight version weighing about 230-250 g/m², providing a good balance for warmth without bulk. This makes it suitable for various outdoor activities and colder days.

The fabric naturally wicks moisture away from the skin and resists odors, which helps keep you dry and fresh during physical activities or long wear. The fit is designed for comfort and daily use, avoiding bunching or overheating that can happen with cotton layers. An added bonus is the inclusion of premium hiking socks, which adds value to the package. Care is straightforward since it’s machine washable, though gentle washing and air drying are recommended to prolong its life.

Heavyweight options might feel too warm for mild conditions, and some users might prefer blended fabrics for added durability or stretch. This base layer is a strong choice for those looking for natural warmth, comfort, and moisture management in a thermal shirt.

The Fruit of the Loom Men's Recycled Waffle Thermal Underwear Crew Top is a solid choice if you're looking for a basic thermal shirt that balances comfort and warmth. Its fabric blend of 52% cotton and 48% recycled polyester makes it soft and eco-friendly, while the waffle-knit texture helps trap heat without feeling too bulky. This shirt does a good job at wicking away moisture, which means it can keep you dry during light activity or daily wear. The tagless label adds to comfort by preventing irritation on your neck.

It features a regular cut that may not be very snug or tailored. The shirt is lightweight enough for layering and includes only the top, so you'll need to purchase bottoms separately if you want a full set. This shirt is best suited for casual cold-weather wear or as a base layer for mild outdoor activities rather than heavy-duty winter sports.

This Carhartt men's thermal shirt is made from 100% polyester with Force technology designed to wick moisture and dry quickly, making it good for staying dry during active or cold weather use. The fabric is lightweight and comfortable, which suits layering under other clothes. It also has odor-fighting properties to keep you feeling fresh after extended wear. The flatlock seam construction is a nice touch as it helps prevent chafing, which is important for comfort during long days.

A thoughtful feature is the concealed thumb loop, which can keep the sleeves in place when layering or moving around. Fit-wise, the advice to size up if you're between sizes is useful since the fit can run snug, typical for performance thermal shirts. The tagless label adds to comfort by avoiding irritation on the neck. Because it’s 100% polyester, it may not feel as soft or breathable as natural fibers like cotton or merino wool, and some people might find it less warm on very cold days without additional layers.

This shirt serves as a solid choice for men needing a reliable moisture-wicking base layer that moves sweat away quickly and reduces odor, making it ideal for work or casual wear in cool to moderately cold conditions.