10 Best Thermal Underwear Set 2025 in the United States

The Amazon Essentials Thermal Long Johns Underwear Set for Men in Medium, Black, is designed with a slim fit that contours well to the body. This ensures the top fits snugly through the shoulders, chest, and waist, and the bottoms fit well around the hips and thighs with a tapered leg opening. The set is crafted from a 60% cotton and 40% polyester blend, providing a soft and breathable feel due to its waffle knit fabric.

This contributes to lightweight warmth, making it suitable for cold weather without being bulky. However, users might need to layer up in extremely cold conditions as it’s designed more for moderate cold weather. The cotton-poly blend allows for decent moisture-wicking, keeping you dry, although it might not be as efficient as fully synthetic fabrics in this regard. The fabric blend also offers moderate odor resistance, but it may fall short compared to materials specifically treated for odor control.

The set is machine washable and designed for everyday durability, making it a practical option for regular use. However, the durability can be limited by the cotton content, as it may wear out faster than pure synthetic options. This thermal underwear set is especially appealing for those seeking an affordable and comfortable option for moderate cold climates and everyday activities rather than extreme outdoor conditions.

The Cuddl Duds Thermal Underwear Set for Women is a solid choice for those looking to stay warm in cold weather. Made from 93% polyester and 7% spandex, the material is both comfortable and stretchy, ensuring a snug fit. The brushed fleece inside and matte soft outside offer a cozy feel, while the spandex stretch provides ease of movement. This set is designed to be heavyweight, which means it can handle very cold conditions well. Its moisture-wicking fabric helps keep you dry by absorbing and evaporating sweat, which is a big plus for active wearers.

The set includes thoughtful design elements like thumbhole sleeves, modern rise leggings, and a tag-free label, which add to the comfort and practicality. Its sleek design makes it versatile enough to wear as a base layer or on its own, making it suitable for both outdoor activities and lounging at home. The protection from harmful UV rays is an added bonus, especially for those spending time outside.

Durability appears to be strong with densely knit fabric, but like any clothing, it will need proper care to maintain its quality over time. Machine washing is convenient, and the set's design and material make it a durable option. This thermal underwear set is ideal for women who need reliable warmth and comfort in cold weather without sacrificing style or mobility.

The Merino.tech Merino Wool Base Layer Set is a midweight thermal underwear set designed for men. This set includes a top, bottom, and a bonus pair of merino wool hiking socks, making it a comprehensive package. Made from 100% superfine 17.5-micron merino wool, it promises exceptional comfort without the itchiness that can accompany wool fabrics.

The material is notable for its moisture-wicking and odor-resistant properties, ensuring you stay dry and fresh even during extended wear. The breathability of merino wool helps regulate body temperature, making this set suitable for year-round use. However, the care instructions recommend hand washing and air drying for longevity, which may be less convenient for some users.

The set is imported and weighs one pound, making it reasonably lightweight. The fit is designed to avoid bunching and overheating, which adds to its comfort during daily wear. While the durability is not explicitly mentioned, the promise from Merino.tech to ensure customer satisfaction suggests a commitment to quality. This set would be ideal for individuals looking for comfortable, moisture-wicking thermal underwear with added benefits like odor resistance and temperature regulation, though the maintenance requirements may be a drawback for those seeking easier care options.