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10 Best Thermals 2025 in the United States
#1
Winner
Merino.tech Merino Wool Base Layer Mens Set - Heavyweight, Midweight, Lite Merino Wool Thermal Underwear For Men Top, Bottom (Large, 250 Black)
The Merino.tech Merino Wool Base Layer Mens Set stands out for anyone needing reliable thermal underwear. This midweight set, weighing 250 g/m², offers an excellent balance of warmth and breathability, making it suitable for various weather conditions. One of its major strengths is the use of 100% superfine merino wool, which provides a super soft feel and exceptional comfort without the itchiness associated with some wool products. This set is particularly appealing for outdoor enthusiasts as it features natural moisture-wicking and odor-resistant properties, helping wearers stay dry and fresh throughout the day.
Rating
10.0
Chosen by1,413
Material
Weight
Fit
Most important from
2243 reviews
#2
Cuddl Duds Thermal Underwear for Women - Women's Cold Weather Clothes Fleece Lined Thermal Long Johns Set - Winter Base Layer Clothing Thermal Shirt Top and Leggings Pants 2Pc Set for Women - Black XL
The Cuddl Duds Thermal Underwear set for women is designed to keep you warm and comfortable in cold weather thanks to its brushed fleece lining inside and a smooth, soft outer layer. Made mainly from polyester with some spandex, it offers a good stretch that allows easy movement and a snug fit without feeling tight, which is great for active days or lounging. The fabric is heavyweight and densely knit, providing decent warmth without bulk, making it suitable as a base layer under other clothes or worn alone for casual wear.
Rating
9.4
Material
Weight
Fit
Most important from
3522 reviews
#3
WEERTI Thermal Underwear for Men Long Johns with Fleece Lined Base Layer Men Cold Weather Top Bottom Black
The WEERTI Thermal Underwear for Men Long Johns are designed to provide excellent insulation and comfort during cold weather. Made from 92% polyester and 8% spandex, the material is both lightweight and stretchy, allowing for a snug fit that minimizes heat loss without restricting movement. This makes it suitable for layering under various types of clothing, from casual outfits to formal wear. The fleece lining adds an extra layer of warmth, ensuring you stay cozy in chilly conditions.
Rating
8.8
Material
Fit
Moisture-Wicking
Most important from
11857 reviews
Top 10 Best Thermals 2025 in the United States
#1
Winner
Merino.tech Merino Wool Base Layer Mens Set - Heavyweight, Midweight, Lite Merino Wool Thermal Underwear For Men Top, Bottom (Large, 250 Black)
Merino.tech Merino Wool Base Layer Mens Set - Heavyweight, Midweight, Lite Merino Wool Thermal Underwear For Men Top, Bottom (Large, 250 Black)
Material: 100% merino wool
Weight: 250 g/m²
Layering Compatibility: fits comfortably under other clothing
Moisture-Wicking: natural moisture-wicking
Durability: hand wash recommended, machine-washable
Chosen by 1413 this week
Cuddl Duds Thermal Underwear for Women - Women's Cold Weather Clothes Fleece Lined Thermal Long Johns Set - Winter Base Layer Clothing Thermal Shirt Top and Leggings Pants 2Pc Set for Women - Black XL
Cuddl Duds Thermal Underwear for Women - Women's Cold Weather Clothes Fleece Lined Thermal Long Johns Set - Winter Base Layer Clothing Thermal Shirt Top and Leggings Pants 2Pc Set for Women - Black XL
Material: 93% Polyester, 7% Spandex
Weight: around 15 ounces
Fit: snug fit, not tight
Layering Compatibility: works as base layer
Moisture-Wicking: yes
Durability: durable, machine washable
WEERTI Thermal Underwear for Men Long Johns with Fleece Lined Base Layer Men Cold Weather Top Bottom Black
WEERTI Thermal Underwear for Men Long Johns with Fleece Lined Base Layer Men Cold Weather Top Bottom Black
Material: 92% polyester/ 8% spandex
Fit: snug
Layering Compatibility: suitable for layering
Moisture-Wicking: efficiently wicks away sweat
Durability: strong seams, 4-way stretch fabric
Merino.tech Merino Wool Base Layer Women Set - Heavyweight, Lite, Midweight Merino Thermal Underwear For Women Top, Bottom (X-Large, 250 Charcoal Grey)
Merino.tech Merino Wool Base Layer Women Set - Heavyweight, Lite, Midweight Merino Thermal Underwear For Women Top, Bottom (X-Large, 250 Charcoal Grey)
Material: 100% Merino Wool
Weight: 9.6 ounces
Layering Compatibility: suitable for various weather
Moisture-Wicking: natural moisture-wicking
Durability: could be improved
Merino.tech Merino Wool Base Layer - Mens 100% Merino Wool Long Sleeve Thermal Shirts Heavyweight, Midweight, Lite with Socks (Medium, Black 250)
Merino.tech Merino Wool Base Layer - Mens 100% Merino Wool Long Sleeve Thermal Shirts Heavyweight, Midweight, Lite with Socks (Medium, Black 250)
Material: 100% superfine Merino wool
Weight: 4.8 ounces
Fit: pull-on top
Layering Compatibility: good for layering
Moisture-Wicking: naturally pulls sweat away
Durability: less durable than blends
Related Products
Under Armour Men's ColdGear Armour Compression Mock, Black (001)/White, Large
Under Armour Men's ColdGear Armour Compression Mock, Black (001)/White, Large
Material: 100% Knit
Weight: 1.4 Pounds
Fit: Ultra-tight, second-skin fit
Layering Compatibility: Ideal for layering under jackets
Moisture-Wicking: Yes
Durability: Enhanced comfort and durability
Merino Wool Base Layer Mens Bottom Pants 100% Merino Wool Heavyweight, Midweight, Lite Thermal Underwear Long Johns and Socks (Medium, Black 250)
Merino Wool Base Layer Mens Bottom Pants 100% Merino Wool Heavyweight, Midweight, Lite Thermal Underwear Long Johns and Socks (Medium, Black 250)
Material: 100% superfine Merino wool
Weight: 4.8 ounces
Fit: Pull-on
Layering Compatibility: suitable for layering without bulk
Moisture-Wicking: naturally wicks moisture from skin
Durability: durable for regular use
Merino Wool Base Layer Women Pants 100% Merino Wool Leggings Heavyweight, Midweight, Lite Thermal Underwear Bottom and Socks (XX-Large, Black 250)
Merino Wool Base Layer Women Pants 100% Merino Wool Leggings Heavyweight, Midweight, Lite Thermal Underwear Bottom and Socks (XX-Large, Black 250)
Material: 100% Merino Wool
Weight: 4.8 ounces
Fit: Pull On
Layering Compatibility: lightweight, midweight, heavyweight
Moisture-Wicking: Yes
Durability: Generally good
WEERTI Thermal Underwear for Women Long Johns with Fleece Lined, Base Layer Women Cold Weather Top Bottom Black
WEERTI Thermal Underwear for Women Long Johns with Fleece Lined, Base Layer Women Cold Weather Top Bottom Black
Material: 92% Microfiber & 8% Spandex
Weight: lightweight
Fit: snug fit
Layering Compatibility: comfortable under various layers
Moisture-Wicking: strong
Durability: might be a concern
#10
romision Thermal Underwear for Men, Fleece Lined Long Johns Hunting Gear Base Layer Bottom Top Set for Cold Weather A-Black
romision Thermal Underwear for Men, Fleece Lined Long Johns Hunting Gear Base Layer Bottom Top Set for Cold Weather A-Black
Material: 90% polyester, 10% spandex
Weight: 200g/m²
Fit: seamless, tagless, crew neck, raglan
Layering Compatibility: comfortable layering under other garments
Moisture-Wicking: yes
Durability: less durable than heavier wool options
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Buying Guide for the Best Thermals
When it comes to buying thermals, it's important to choose the right product to keep you warm and comfortable in cold weather. Thermals are designed to provide insulation and retain body heat, making them essential for outdoor activities, winter sports, or simply staying warm during chilly days. To make an informed decision, you need to consider several key specifications that will help you find the best fit for your needs.MaterialThe material of thermals is crucial because it determines the level of warmth, comfort, and moisture-wicking ability. Common materials include wool, synthetic fibers, and cotton. Wool, especially merino wool, is excellent for warmth and moisture-wicking but can be more expensive. Synthetic fibers like polyester are good for moisture-wicking and are often more affordable, but they may not be as warm as wool. Cotton is comfortable but not ideal for moisture-wicking, making it less suitable for intense activities. Choose wool for maximum warmth and moisture control, synthetic for a balance of performance and cost, and cotton for casual, low-activity use.
WeightThermals come in different weights, which affect their warmth and bulkiness. Lightweight thermals are suitable for mild cold and high-activity levels, as they provide some warmth without causing overheating. Midweight thermals offer a balance of warmth and breathability, making them versatile for various activities and moderate cold. Heavyweight thermals provide maximum warmth and are best for extremely cold conditions or low-activity levels. Select lightweight for mild conditions or high activity, midweight for versatile use, and heavyweight for extreme cold or low activity.
FitThe fit of thermals is important for comfort and effectiveness. A snug fit ensures that the thermals can trap body heat and wick away moisture efficiently. However, they should not be too tight, as this can restrict movement and cause discomfort. Loose-fitting thermals may not provide adequate insulation. Look for a fit that is close to the body but allows for a full range of motion. Consider your activity level and personal comfort preferences when choosing the fit.
Layering CompatibilityThermals are often used as a base layer, so it's important to consider how they will work with other layers of clothing. They should be thin enough to fit comfortably under other garments without causing bulkiness. Additionally, they should have good moisture-wicking properties to keep you dry when layered. Think about the types of outer layers you will be wearing and ensure that your thermals can be easily layered without compromising comfort or mobility.
Moisture-WickingMoisture-wicking is the ability of the fabric to draw sweat away from your skin and allow it to evaporate. This is important for maintaining comfort and preventing chills, especially during physical activities. Wool and synthetic materials generally have good moisture-wicking properties, while cotton does not. If you plan to engage in activities that cause sweating, prioritize thermals with excellent moisture-wicking capabilities to stay dry and comfortable.
DurabilityDurability refers to how well the thermals can withstand wear and tear over time. High-quality materials and construction will ensure that your thermals last longer and maintain their performance. Look for reinforced seams, high-quality stitching, and materials known for their durability. If you plan to use your thermals frequently or for demanding activities, investing in durable options will provide better long-term value.