Get 20% Off with Your Order
Use Code: SWEAT20 at Checkout

Limited Time Offer: Ends Tonight

SALE ENDS IN

★★★★★ Over 10,000+ 5 Star Reviews

Say Goodbye to Embarrassing Sweat Stains and Deodorant Marks.
Stay Dry and Comfortable All Day.

A person with long dark hair poses with one arm raised, wearing The Signature Undershirt by Numi in light beige, and looking off to the side.
A woman with long dark hair stands facing forward, wearing a light beige short-sleeve top and light brown pants against a plain background. Her Signature Undershirt by Numi ensures she stays comfortable even in the heat, thanks to its sweat-proof design.
A person with long, dark hair is shown from the back wearing The Signature Undershirt in light pink and matching bottoms from Numi against a plain background.
A woman wearing The Signature Undershirt from Numi, a gray fitted t-shirt featuring a hip length, sweat-proof material, reversible neckline, short seamless sleeves with a raw edge, and a slim fit ideal for layering.
Image split in half: the left side features a close-up of The Signature Undershirt's beige sweat-proof underarm shield by Numi in action, while the right side shows a model wearing a beige top. Text highlights product benefits like effective sweat protection, exceptional comfort, and versatile heat-friendly layering options.
Close-up of The Signature Undershirt by Numi in beige, with text detailing features: sweat-proof, all-day comfort, lightweight, 4-way stretch, thermo-regulating material to manage heat, and a durable design to prevent shrinking and fading.
Comparison chart showing Numi's The Signature Undershirt vs. Other T-Shirts. The Signature Undershirt by Numi features built-in underarm shields to stop sweat stains and odors, provides comfortable invisible shields, has seamless sleeves, and is made from breathable fabric.
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A person with long dark hair poses with one arm raised, wearing The Signature Undershirt by Numi in light beige, and looking off to the side.
A woman with long dark hair stands facing forward, wearing a light beige short-sleeve top and light brown pants against a plain background. Her Signature Undershirt by Numi ensures she stays comfortable even in the heat, thanks to its sweat-proof design.
A person with long, dark hair is shown from the back wearing The Signature Undershirt in light pink and matching bottoms from Numi against a plain background.
A woman wearing The Signature Undershirt from Numi, a gray fitted t-shirt featuring a hip length, sweat-proof material, reversible neckline, short seamless sleeves with a raw edge, and a slim fit ideal for layering.
Image split in half: the left side features a close-up of The Signature Undershirt's beige sweat-proof underarm shield by Numi in action, while the right side shows a model wearing a beige top. Text highlights product benefits like effective sweat protection, exceptional comfort, and versatile heat-friendly layering options.
Close-up of The Signature Undershirt by Numi in beige, with text detailing features: sweat-proof, all-day comfort, lightweight, 4-way stretch, thermo-regulating material to manage heat, and a durable design to prevent shrinking and fading.
Comparison chart showing Numi's The Signature Undershirt vs. Other T-Shirts. The Signature Undershirt by Numi features built-in underarm shields to stop sweat stains and odors, provides comfortable invisible shields, has seamless sleeves, and is made from breathable fabric.

The Signature Undershirt

Elevate Your Outfit: Say Hello to the Better Base Layer

Meet our #1 best seller, The Signature. This OG undershirt is the ultimate base-layer for every outfit. No more sweat-stains or deodorant marks – stay fresh and feel clean all day with this game-changer. With 250,000+ sold worldwide, The Signature Undershirt is the real deal.

1343 reviews

#1 Best Seller

$70.00
$70.00

Get 20% OFF with code SWEAT20

SALE ENDS IN

Meet our #1 best seller, The Signature Undershirt. This OG undershirt is the ultimate base-layer for every outfit. No more sweat-stains or deodorant marks - stay fresh and feel clean all day with this game-changer. With 250,000+ sold worldwide, the Signature Undershirt is the real deal. 

Color

30 Day Money Back Guarantee

On U.S. & Canada orders

Easy Returns

On U.S. & Canada orders

Free Shipping

On orders over $150

Secure Checkout

On all orders

As Featured In

Get ready to feel exceptional comfort and unstoppable confidence with Numi undershirts. Engineered with our exclusive Contemporary Cotton™ sweat-proof shield technology, say goodbye to embarrassing sweat stains and unwanted odor. Our innovative fabric safeguards your clothes, ensuring you stay fresh and dry throughout the day. Made from Tencel, our 4-way stretch fabric offers luxurious softness and an unbeatably comfortable fit, while providing unmatched breathability.

Stop Settling: Why Your Regular T-Shirt Isn't Cutting It as a Base Layer

Are you tired of your typical t-shirt failing to provide the comfort and functionality you need? It's time for a change. Let's face it: relying on a regular old t-shirt as a base layer just doesn’t cut it. Whether it's inadequate moisture management, lack of odor control, or discomfort due to seams and tightness, your current go-to isn't up to the task. But fear not! Upgrade to a base layer that offers seamless design, moisture-wicking magic, and a fit that flatters. Say goodbye to compromises and hello to ultimate comfort and performance.

✓ Stops Sweat Stains 

✓ Protects Clothes

✓ Stops Deo Marks 

✓ Feels Amazing

Sweat

STOPS SWEAT STAINS

Sweat

ABSORBS MOISTURE & ODOR

Sweat

LIGHTWEIGHT & BREATHABLE

Sweat

4-WAY STRETCH

FitsTrueToSize-100x100.png__PID:7ca3a884-dc8b-499c-b177-0dfb3d5d5c6c

FITS TRUE TO SIZE

AlmondSignature-1800x1800.png__PID:c13a1c9d-979e-4628-b2e6-356512d44e6e

EFECTIVE SWEAT-PROOF TECHNOLOGY = NO STAINS

Say goodbye to embarrassing sweat stains with advanced technology that stops sweat in its tracks, absorbing moisture and odor away from your body. This innovative solution keeps clothes dry and clean, ensuring confidence and comfort throughout the day.

StopSweat-100x100-Icon.png__PID:2af92266-6a42-43d1-9b3a-4053b7480603

Stops Sweat Stains

OdorResistant-100x100-Icon.png__PID:f3579f39-47c4-4d7e-a59e-779c7ec0c30b

Absorbs moisture & odor

Bean-filled to sit in an upright position

ULTRA SOFT, LIGHTWEIGHT AND EXTREMELY COMFORTABLE

Stay cool and dry with breathable, thermoregulating fabric made from 90% Modal and featuring 10% Lycra® for 4-way stretch. Experience all-day comfort with this innovative blend.

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Lightweight & Breathable

4WayStretch-100x100.png.webp__PID:4b287b56-821d-4126-97a3-56aeb1a8bae1

4 - Way Stretch (10% Lycra®)

Bean-filled to sit in an upright position

AlmondSignature-1800x1800.png__PID:c13a1c9d-979e-4628-b2e6-356512d44e6e
Top3-Alt.jpg__PID:32736c3c-bd7d-411d-9da5-8a1acd15eb08

A VERSATILE, FLATTERING FIT

Achieve seamless elegance with our slim-fit design that remains invisible under clothing. Tailored to be fitted yet never tight, our range comes in 6 styles and 7 colors to compliment any outfit

StopSweat-100x100-Icon.png__PID:2af92266-6a42-43d1-9b3a-4053b7480603

Stops Sweat Stains

OdorResistant-100x100-Icon.png__PID:f3579f39-47c4-4d7e-a59e-779c7ec0c30b

Absorbs moisture & odor

Bean-filled to sit in an upright position

Make the Switch

Invest in a Better Base Layer.

We Make It Easy For You

30 Day Money Back Guarantee

Experience peace of mind with our 30-day money-back guarantee. If you're not completely satisfied with your purchase, simply return it for a full refund—no questions asked.

Free Shipping

Enjoy the convenience of free shipping on all orders over $150. No matter where you are, we'll deliver your items straight to your doorstep without any extra cost.

Choose from 6 style and 7 colours

Express your unique style with our versatile options for different outfits. Choose from a selection of six styles and seven colors to find the perfect match for your wardrobe.

Here's What Our Customers Say

I Love the fit and materials of my Numi classic shirt. It really protects the outerwear sweaters and jackets and other long sleeves from my sweat.. That says a lot.!!

Brooke L.

✓ Verified Purchase

I had a blouse that showed perspiration stains - it was frustrating to use adhesive pads. I am beyond happy with my signature undershirt. It is lightweight, comfy and works to prevent perspiration stains, just as advertised. Best part? Canadian company and made in Canada!

Alison T.

✓ Verified Purchase

Bought this to wear under sweaters and it is perfect! Soft, stretchy and comfy. I’ll be buying more.

Leslie B.

✓ Verified Purchase

The Difference Is Clear

CHOOSE NUMI

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Ditch Your T-Shirt and Experience the Numi Secret

carim1111__u_g_c_gifting_1_undershirt_2021_09_15_04_13_55.jpg__PID:0f519a68-fb69-4ef8-9d27-960f2d1e9861
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How we compare - Mobile-ALT.jpg__PID:96733c81-e9b9-42c6-987d-1fa6e9cc4646

Elevate Your Everyday Essentials

Discover our Bestsellers

A person with long dark hair poses with one arm raised, wearing The Signature Undershirt by Numi in light beige, and looking off to the side.
A woman with long dark hair stands facing forward, wearing a light beige short-sleeve top and light brown pants against a plain background. Her Signature Undershirt by Numi ensures she stays comfortable even in the heat, thanks to its sweat-proof design.
A person with long, dark hair is shown from the back wearing The Signature Undershirt in light pink and matching bottoms from Numi against a plain background.
A woman wearing The Signature Undershirt from Numi, a gray fitted t-shirt featuring a hip length, sweat-proof material, reversible neckline, short seamless sleeves with a raw edge, and a slim fit ideal for layering.
Image split in half: the left side features a close-up of The Signature Undershirt's beige sweat-proof underarm shield by Numi in action, while the right side shows a model wearing a beige top. Text highlights product benefits like effective sweat protection, exceptional comfort, and versatile heat-friendly layering options.
Close-up of The Signature Undershirt by Numi in beige, with text detailing features: sweat-proof, all-day comfort, lightweight, 4-way stretch, thermo-regulating material to manage heat, and a durable design to prevent shrinking and fading.
Comparison chart showing Numi's The Signature Undershirt vs. Other T-Shirts. The Signature Undershirt by Numi features built-in underarm shields to stop sweat stains and odors, provides comfortable invisible shields, has seamless sleeves, and is made from breathable fabric.
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A person with long dark hair poses with one arm raised, wearing The Signature Undershirt by Numi in light beige, and looking off to the side.
A woman with long dark hair stands facing forward, wearing a light beige short-sleeve top and light brown pants against a plain background. Her Signature Undershirt by Numi ensures she stays comfortable even in the heat, thanks to its sweat-proof design.
A person with long, dark hair is shown from the back wearing The Signature Undershirt in light pink and matching bottoms from Numi against a plain background.
A woman wearing The Signature Undershirt from Numi, a gray fitted t-shirt featuring a hip length, sweat-proof material, reversible neckline, short seamless sleeves with a raw edge, and a slim fit ideal for layering.
Image split in half: the left side features a close-up of The Signature Undershirt's beige sweat-proof underarm shield by Numi in action, while the right side shows a model wearing a beige top. Text highlights product benefits like effective sweat protection, exceptional comfort, and versatile heat-friendly layering options.
Close-up of The Signature Undershirt by Numi in beige, with text detailing features: sweat-proof, all-day comfort, lightweight, 4-way stretch, thermo-regulating material to manage heat, and a durable design to prevent shrinking and fading.
Comparison chart showing Numi's The Signature Undershirt vs. Other T-Shirts. The Signature Undershirt by Numi features built-in underarm shields to stop sweat stains and odors, provides comfortable invisible shields, has seamless sleeves, and is made from breathable fabric.
$70.00
$70.00

The Signature Undershirt

A woman wearing Numi's sweat-proof light pink
Rear view of a person with long dark hair wearing The Crop Undershirt by Numi in light pink, paired with beige leggings, standing against a plain background.
Person with long dark hair wearing a white Numi Crop Undershirt and light brown pants, standing against a plain background.
A person with long dark hair is seen from behind wearing The Crop Undershirt by Numi, paired with beige pants against a plain background.
A woman wearing a black pair of pants and
A woman wearing the Numi Crop Undershirt in beige demonstrates its sweat-proof, odor-resistant underarm shields. Icons highlight the fabric's sweat and stain protection, comfort, cost-saving benefits, and suitability for layering.
The Crop Undershirt - Numi
The Crop Undershirt - Numi
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A woman wearing Numi's sweat-proof light pink
Rear view of a person with long dark hair wearing The Crop Undershirt by Numi in light pink, paired with beige leggings, standing against a plain background.
Person with long dark hair wearing a white Numi Crop Undershirt and light brown pants, standing against a plain background.
A person with long dark hair is seen from behind wearing The Crop Undershirt by Numi, paired with beige pants against a plain background.
A woman wearing a black pair of pants and
A woman wearing the Numi Crop Undershirt in beige demonstrates its sweat-proof, odor-resistant underarm shields. Icons highlight the fabric's sweat and stain protection, comfort, cost-saving benefits, and suitability for layering.
The Crop Undershirt - Numi
The Crop Undershirt - Numi
$65.00
$65.00

The Crop Undershirt

The Square Neck Cap Sleeve Undershirt - Numi
The Square Neck Cap Sleeve Undershirt - Numi
The Square Neck Cap Sleeve Undershirt - Numi
The Square Neck Cap Sleeve Undershirt - Numi
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The Square Neck Cap Sleeve Undershirt - Numi
The Square Neck Cap Sleeve Undershirt - Numi
The Square Neck Cap Sleeve Undershirt - Numi
The Square Neck Cap Sleeve Undershirt - Numi
$70.00
$70.00

The Square Neck Cap Sleeve Undershirt

A person with short dark hair and fair skin is wearing The Lace Undershirt by Numi, a white sweat-proof short-sleeve top, paired with beige pants, standing against a plain backdrop.
A woman with short dark hair is standing with her back turned, wearing a white, sweat-proof undershirt called The Lace Undershirt from Numi and light brown shorts against a plain background.
A woman in
A person with long dark hair is wearing The Lace Undershirt by Numi in beige, paired with matching sweat-proof pants, and standing against a plain light background.
A person with long dark hair, wearing a beige short-sleeve top over The Lace Undershirt by Numi and light brown pants, viewed from the back against a plain light background.
A woman wearing The Lace Undershirt by Numi, featuring short cap sleeves, a reversible neckline, a slim fit perfect for layering as an undershirt, and elegant lace trim detailing.
Image showing a woman wearing The Lace Undershirt by Numi in light beige. Features highlighted include sweat-proof and stain protection, all-day comfort, time and money savings, and easy layering. Text at bottom reads:
The Lace Undershirt - Numi
The Lace Undershirt - Numi
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A person with short dark hair and fair skin is wearing The Lace Undershirt by Numi, a white sweat-proof short-sleeve top, paired with beige pants, standing against a plain backdrop.
A woman with short dark hair is standing with her back turned, wearing a white, sweat-proof undershirt called The Lace Undershirt from Numi and light brown shorts against a plain background.
A woman in
A person with long dark hair is wearing The Lace Undershirt by Numi in beige, paired with matching sweat-proof pants, and standing against a plain light background.
A person with long dark hair, wearing a beige short-sleeve top over The Lace Undershirt by Numi and light brown pants, viewed from the back against a plain light background.
A woman wearing The Lace Undershirt by Numi, featuring short cap sleeves, a reversible neckline, a slim fit perfect for layering as an undershirt, and elegant lace trim detailing.
Image showing a woman wearing The Lace Undershirt by Numi in light beige. Features highlighted include sweat-proof and stain protection, all-day comfort, time and money savings, and easy layering. Text at bottom reads:
The Lace Undershirt - Numi
The Lace Undershirt - Numi
$70.00
$70.00

The Lace Undershirt