10 Best Thermals 2025 in the United States

The Thermajohn Long Johns Thermal Underwear is made from a blend of 92% polyester and 8% spandex, featuring a soft fleece lining that provides a cozy and comfortable feel. This material choice helps the underwear maintain warmth while allowing some stretch for a good fit, which is important for comfort and effective layering. Weighing about 14 ounces, the set is lightweight enough to be worn under regular clothes without feeling bulky.

Its moisture-wicking fabric does a good job of keeping sweat away, which helps you stay dry during physical activity or long wear in cold weather. The fit is designed to be snug but flexible, making it easy to layer over or under other garments, which is essential for adapting to different temperatures. While the product is machine washable and promises durability, the synthetic fabric blend may not be as long-lasting as some high-end natural fibers, and might not be as breathable in extremely active or wet conditions.

These long johns provide a practical and comfortable option for men looking to stay warm in cold weather with good moisture control and layering capability, though they may feel less natural than cotton or wool alternatives.

The Thermajane Long Johns Thermal Underwear for women is designed to be a cozy and practical base layer for cold weather. Made from a blend of mostly polyester with some spandex, it offers a good balance of softness and stretch, helping it fit snugly while allowing freedom of movement. The fleece lining adds extra warmth and a soft feel against the skin, which is great for wearing comfortably for long periods, whether at home or outdoors.

This thermal wear is moisture-wicking, helping to keep sweat away from the skin and reduce odor, which is important for staying dry and comfortable during active use. The fabric's 4-way stretch enhances fit and layering compatibility, making it easy to wear under other clothes without feeling bulky. While the fabric is primarily synthetic, which may be less breathable compared to natural fibers like merino wool or cotton blends, the fleece lining indicates it is well-suited for cold weather conditions.

The durability of the polyester-spandex blend supports solid wear, and the thermal underwear is a reliable and soft option for women seeking warmth and moisture control with a flexible fit, especially for casual or moderately active use in chilly environments.

The Amazon Essentials Thermal Long Johns for Men are designed to deliver lightweight warmth without feeling bulky, making them a good choice for cold weather layering. Made from a cotton-polyester blend (60% cotton, 40% polyester), they offer softness and breathability thanks to the waffle knit pattern, which helps with moisture-wicking but may not be as efficient as specialized synthetic fabrics. The slim fit design contours to the body, providing a snug feel around the shoulders, chest, hips, and thighs; this can enhance layering because it avoids excess bulk, but may feel tight for those who prefer looser garments.

The elastic waist and ribbed cuffs on the bottoms help keep the underwear in place during movement, contributing to comfort throughout the day. At just 8 ounces, the set is lightweight and suitable for wearing under other clothing without restriction. While the cotton content adds comfort, it can retain moisture longer than some advanced fabrics, so it might not be ideal for high-intensity activities where heavy sweating occurs.

Durability appears decent for everyday use, supported by Amazon Essentials' reputation for affordable yet reliable basics. Machine washable care makes maintenance easy. These thermals provide a solid budget-friendly option for men seeking comfortable, slim-fitting long johns for casual cold weather use and layering, though those needing high-performance moisture control or a looser fit might want to explore other options.