10 Best Thermal Underwear Sets 2025 in the United States

The Cuddl Duds Thermal Underwear set is designed to keep you warm and comfortable in cold weather, thanks to its cozy fleece lining and heavyweight feel. Made from 93% polyester and 7% spandex, it offers a good stretch that moves with you, making it comfortable for active wear or lounging. The moisture-wicking fabric helps keep sweat away from your skin, which is great for staying dry and warm during physical activities. Plus, it offers built-in UV protection with a rating of 50+, which is a nice bonus if you plan to wear it outdoors. The fit is modern and close to the body without being bulky, featuring details like thumbholes in the sleeves and a higher rise in the leggings for added comfort and coverage.

The product is machine washable and lightweight at about 15 ounces. Durability is generally solid given the dense knit fabric, but as with many polyester blends, it may pill over time with heavy use. This set is well suited for women looking for a warm, stretchy base layer that can double as casual wear in cold seasons.

The Cuddl Duds Women's Thermal Underwear set is designed for cold weather with a heavyweight fabric that includes a soft, brushed fleece inside for warmth and a smooth outside for comfort. Made from mostly polyester with some spandex, it offers good stretch, making it comfortable for active wear. The moisture-wicking feature helps keep you dry by pulling sweat away from your body, which is great for staying comfortable during physical activities or long days outside. It also provides strong UV protection, a nice bonus for outdoor use.

This set fits well with a modern rise in the leggings and thumbhole sleeves in the top, adding to the cozy, close-to-skin feel without bulk. The fabric blend should hold up well over time, and the tag-free label adds extra comfort. While it keeps you warm and dry, the synthetic material may not be as breathable as natural fibers for some people.

This set is a reliable, warm base layer that’s stretchy and comfortable for winter days, whether for layering or wearing on its own at home.

The Fruit of the Loom Men's Recycled Premium Waffle Thermal Underwear Bottoms offer a comfortable and practical option for staying warm in cold to moderately cold weather. Made from a soft waffle-knit fabric combining 52% cotton and 48% recycled polyester, they provide good insulation without feeling bulky. The material mix helps wick away moisture and dry quickly, which is great if you tend to sweat or wear them for active use. The fit is pull-on style, which makes them easy to wear under other clothing, though they may not be as snug as some performance-focused thermals. Reinforced flat seams contribute to durability and reduce irritation from chafing. While the fabric doesn’t specifically mention odor resistance, the polyester content and quick-dry properties can help keep odors in check during moderate use.

These long johns are ideal for everyday winter wear or layering during outdoor activities but might not be the best choice for intense cold or high-performance sports. The value is enhanced by available multi-packs, making them a practical investment for those seeking warmth and comfort without a premium price.