10 Best Mens Thermals 2025 in the United States

The Merino.tech Merino Wool Base Layer Set is an excellent choice for men seeking high-quality thermal underwear. Made from 100% superfine 17.5-micron merino wool, this midweight set (250 g/m²) includes both a top and bottom, making it perfect for cold weather. The material is soft, comfortable, and non-itchy, making it suitable for all-day wear. One standout feature is its moisture-wicking and odor-resistant properties, which help keep you dry and fresh throughout the day.

This set is also breathable and naturally regulates body temperature, offering comfort in varying climates. However, it's worth noting that the set requires hand washing and air drying for longevity, which might not be convenient for everyone. Additionally, while the product’s durability is generally good, merino wool can be more delicate than synthetic fabrics and may require careful handling.

The inclusion of free Merino Wool Hiking Socks adds value to the purchase, making it a thoughtful gift. If you prioritize natural materials and comfort, this base layer set is a great investment despite the extra care needed for maintenance.

The WEERTI Thermal Underwear for Men appears to be a solid choice for cold weather layering. Made from 92% polyester and 8% spandex, the material blend offers a good balance of stretch and comfort. The fleece lining ensures additional warmth, making it suitable for chilly conditions. The fabric is lightweight, which enhances comfort when worn under other clothing without feeling bulky.

Its snug fit is designed to minimize heat loss, functioning well as a base layer that can be discreetly worn under various outfits, from casual to formal attire, or even as pajamas on cold nights. One of its notable features is its strong moisture-wicking properties, which help in keeping the wearer dry by quickly moving sweat away from the body, reducing the clammy feeling often associated with thermal wear. Additionally, the 4-way stretch fabric allows for flexibility and freedom of movement, which is beneficial for activities requiring full mobility.

While the product description does not mention specific odor resistance technology, which could be a drawback for long-term use without frequent washing, the durability aspect is backed by the claim of strong seams. For those seeking reliable, warm, and flexible thermal underwear, WEERTI's offering seems promising, though potential buyers might want to consider additional options if odor resistance is a priority.

The Under Armour Men's HeatGear Armour Leggings are designed for men looking for comfortable and high-performance thermal wear. They are made from a super-light HeatGear fabric, which offers excellent coverage without adding bulk, making them suitable for various activities, especially during warmer weather. The strategic mesh panels enhance ventilation, ensuring that you stay cool while working out or engaging in outdoor activities. With moisture-wicking properties, these leggings quickly draw sweat away from the skin, keeping you dry and comfortable.

The ergonomic design is aimed at increasing durability, with seams placed to avoid high abrasion areas, and the ultra-tight, second-skin fit provides great support. The presence of a drop-in strength pocket adds a practical touch for those who need to carry small items, such as keys or cards.

These leggings stand out as an excellent choice for active men seeking lightweight thermals that provide comfort and support during workouts or outdoor activities. Their moisture-wicking and durability features make them a good investment, especially for those who prioritize performance in their thermal wear.