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 Women Set is a versatile option for those seeking comfortable and functional thermal underwear. Made from 100% superfine Merino wool, this set is designed to provide a soft, itch-free experience, making it a great choice for daily wear. The midweight version at 250 g/m² offers a balanced level of warmth, suitable for various weather conditions. Additionally, the set includes Merino wool hiking socks, adding extra value to the package.

One of the standout features is the natural moisture-wicking and odor-resistant properties of Merino wool, which help keep you dry and fresh throughout the day. Breathability is another strong point, ensuring you stay comfortable without overheating. However, the recommended care instructions to wash on a delicate cycle and lay flat to dry may require extra effort compared to more low-maintenance fabrics. Durability is generally good, but like all natural fibers, Merino wool may require careful handling to avoid damage.

The set is also available in different weights (165 g/m² for lightweight and 320 g/m² for heavyweight), making it adaptable to various temperatures and activities. While the zero-worries guarantee is reassuring, the relatively high price point might be a consideration for some. Originating from China, the product might not appeal to those looking for locally made options.