10 Best Thermals 2025 in the United States

The Cuddl Duds Womens Thermal Underwear 2-piece set is designed for cold weather comfort, featuring a brushed fleece interior that provides substantial warmth without being bulky. Made from a blend of 93% polyester and 7% spandex, it offers good stretch and flexibility, making it comfortable for active wear or lounging. The lightweight 14.89-ounce weight and sleek design allow it to fit well under other layers, supporting layering without restricting movement. Moisture-wicking fabric helps keep you dry by pulling sweat away from your skin, which is essential for staying warm and comfortable during physical activity or fluctuating temperatures. Additionally, the fabric offers protection against UV rays, adding an extra benefit if you're spending time outdoors. The tag-free labels and thumbhole sleeves contribute to all-day comfort.

While the synthetic material supports durability and easy machine washing, it might not feel as natural or breathable as some natural fibers like wool or cotton blends. This set is well suited for those looking for a stretchy, warm base layer that performs well in cold weather and fits snugly for layering, though individuals sensitive to synthetic fabrics might want to consider that aspect.

The WEERTI Thermal Underwear for Men Long Johns are designed to provide excellent insulation and comfort during cold weather. Made from 92% polyester and 8% spandex, the material is both lightweight and stretchy, allowing for a snug fit that minimizes heat loss without restricting movement. This makes it suitable for layering under various types of clothing, from casual outfits to formal wear. The fleece lining adds an extra layer of warmth, ensuring you stay cozy in chilly conditions.

One of the key strengths of this thermal underwear is its moisture-wicking capability. The fabric efficiently wicks away sweat, keeping you dry and preventing that clammy feeling often associated with other thermal wear. This feature enhances comfort, especially during active use or long periods of wear. In terms of durability, the strong seams and 4-way stretch fabric ensure that the thermal underwear can withstand regular use without tearing or losing its shape.

However, because it is imported, availability might be an issue, and it may take some time to receive if ordered online. The fit is described as snug, akin to a second skin, which might not be preferred by those who like looser clothing. Additionally, while the polyester-spandex blend is good for moisture-wicking and flexibility, it might not be as breathable as some natural fibers like merino wool. This thermal underwear set is ideal for men seeking a reliable base layer for cold weather that offers warmth, moisture management, and flexibility, making it a good choice for winter sports, outdoor activities, or even just staying warm indoors.

The Merino.tech Merino Wool Base Layer Set for men offers 100% superfine merino wool fabric, known for its softness and comfort, which helps prevent itchiness often found in wool products. This set includes a midweight shirt and pants (250 g/m²), plus a merino wool beanie, making it a practical choice for cold weather layering. The material naturally wicks moisture away from the body and resists odors, keeping you dry and fresh even during active use. Its breathable nature also helps regulate body temperature, suitable for year-round wear.

The fit is described as comfortable with no bunching or overheating, which is important for layering under other clothing. However, the care instructions recommend hand washing and air drying to maintain durability, which could be less convenient for some users who prefer machine washing. The set is imported and designed specifically for men, available in large size and black oil color. While this base layer excels in comfort and moisture management, its heavyweight design may be better suited for colder climates rather than mild conditions.

This makes it a solid choice for anyone needing reliable thermal wear that balances warmth, comfort, and odor control, especially for outdoor or daily winter activities.