Best M Womens Base Layers in 2026

Material: 87% merino wool, 13% nylon

Insulation Weight: lightweight (150g/m2)

Fit: slim

Odor-resistant

Temperature regulating

Will help keep you cool when your intensity amps up, and its design helps minimize chafing

Odor-resistant

Temperature regulating

Will help keep you cool when your intensity amps up, and its design helps minimize chafing

Material: 53% merino wool, 45% polyester, 2% elastane

Insulation Weight: midweight

Fit: slim

VERSATILE EVERYDAY BASE LAYER. Layer on the comfort with our new quarter zip. This must-have base layer features 100% Merino wool fabric, breathability, moisture-wicking and a body-enhancing fit so you can explore comfortably and look good while doing it.

SLIM FIT. Designed to meet the demands of outdoor adventuring, this slim fit quarter zip shows off a slimming silhouette while offering unrestricted movement through the arms and chest.

WHY MERINO WOOL? Thinner and softer than regular wool, it's easy to wear next to skin. Each fiber transports sweat away as a vapor, wicks moisture (we tested it ourselves) and regulates body temperature to keep you cool in summer and warm in winter.

VERSATILE EVERYDAY BASE LAYER. Whether you're working up a sweat or simply looking to stay warm, these bottoms are up for the challenge. 100% Merino wool fabric enhances breathability so you can stay as comfortable as possible, from exploring to chilling.

MID RISE. Crafted with comfort in mind, this mid rise pant sits high on the hips just slightly below the belly button.

PLUS SIZE — SLIM FIT. Featuring an updated fit to enhance styling for a range of body shapes, this curve fitting bottom is designed to be worn next to skin. It's deal for layering as the weather cools while offering freedom of movement. Inseam: 29"

VERSATILE EVERYDAY BASE LAYER. Layer on the comfort with our new quarter zip. This must-have base layer features 100% Merino wool fabric, breathability, moisture-wicking and a body-enhancing fit so you can explore comfortably and look good while doing it.

SLIM FIT. Designed to meet the demands of outdoor adventuring, this slim fit quarter zip shows off a slimming silhouette while offering unrestricted movement through the arms and chest.

WHY MERINO WOOL? Thinner and softer than regular wool, it's easy to wear next to skin. Each fiber transports sweat away as a vapor, wicks moisture (we tested it ourselves) and regulates body temperature to keep you cool in summer and warm in winter.

Odor-resistant

Temperature regulating

Will help keep you cool when your intensity amps up, and its design helps minimize chafing

100% Merino wool fabric made with an interlock knit for enhanced comfort, breathability, thermoregulation, and odor resistance

Fit updated to improve functionality while enhancing aesthetics for a range of body shapes

Back body seam wraps to front for body-enhancing fit, Crew neck with raglan sleeves

Fit updated to improve functionality while enhancing aesthetics for a range of body shapes. Crew neck with raglan sleeves

SW016369

Flatlock seam construction designed to minimize chafing. Back body seam wraps to front for body-enhancing fit

Material: 52% merino wool, 21% Tencel, 20% polyester, 7% spandex

Insulation Weight: midweight

Fit: form-fitting

PERFORMANCE BASE LAYER. Designed to work with a body in motion, this legging provides a supportive fit for performance and training. Mesh ventilation seamlessly knit in gender-specific zones keeps you dry and comfortable during high-intensity activities.

SLIM FIT. Designed to meet the demands of outdoor adventuring, this slim fit base layer shows off a slimming silhouette while offering unrestricted movement through the arms and chest.

INTRAKNIT ACTIVE MERINO. Built for high-intensity aerobic activities, this lightweight, packable layer balances warmth and breathability with body-mapping to help you train comfortably. When you're battling the wind, this is all you need to get there.

100% Merino wool fabric made with an interlock knit for enhanced comfort, breathability, thermoregulation, and odor resistance

Fit updated to improve functionality while enhancing aesthetics for a range of body shapes

Back body seam wraps to front for body-enhancing fit, Crew neck with raglan sleeves

Responsible Collection: Recycled/Repurposed

Material: 88% merino wool, 12% nylon

Insulation Weight: lightweight

Responsible Collection: Recycled/Repurposed

Material: 88% merino wool, 12% nylon

Insulation Weight: lightweight

Material: 52% merino wool, 45% polyester, 2% elastane, 1% nylon

Insulation Weight: midweight

Fit: slim

Odor-resistant

Temperature regulating

Will help keep you cool when your intensity amps up, and its design helps minimize chafing

WARM WEATHER APPAREL. Work up a sweat but still feel cool in this short sleeve tee. It combines the benefits of Merino wool—thermoregulation, moisture-wicking and moisture management—with Tencel performance fabric for soft, lightweight comfort.

REGULAR FIT. Designed to meet the demands of outdoor adventuring, this regular fit base layer t-shirt offers room to move throughout the silhouette without any additional bulk.

ACTIVE ULTRALITE MERINO. Best for warm weather and blended from Merino and Tencel, this performance fabric is designed to help you stay cool and comfortable while working up a sweat — combining breathability and quick dry times.