![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.](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-2.jpg?v=1716314082&width=1200)
![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.](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-1.jpg?v=1716314082&width=1200)
![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.](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-10.jpg?v=1716314082&width=1200)
![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.](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-5.jpg?v=1716314082&width=1200)
![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.](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-6.jpg?v=1716314082&width=1200)
![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.](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-7.jpg?v=1716314082&width=1200)
![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.](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-8.jpg?v=1716314082&width=1200)
!["#color_almond| Emi is 5'7.5" and wears a size S](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-12.jpg?v=1715721179&width=1200)
!["#color_almond| Emi is 5'7.5" and wears a size S](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-13.jpg?v=1715721179&width=1200)
!["#color_toffee| Tolu is 5'7.5" and wears a size M](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-33.jpg?v=1715721336&width=1200)
!["#color_toffee| Tolu is 5'7.5" and wears a size M](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-35.jpg?v=1715721336&width=1200)
!["#color_black| Siobhan is 5'8.5" and wears a size S](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-22.jpg?v=1715721336&width=1200)
!["#color_black| Siobhan is 5'8.5" and wears a size S](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-24.jpg?v=1715721336&width=1200)
!["#color_white| Siobhan is 5'8.5" and wears a size S](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-16.jpg?v=1715721336&width=1200)
!["#color_white| Siobhan is 5'8.5" and wears a size S](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-18.jpg?v=1715721336&width=1200)
!["#color_HEATHER GREY|Estyr is 5'9", wearing a size XS](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-31.jpg?v=1715721336&width=1200)
!["#color_HEATHER GREY|Estyr is 5'9", wearing a size XS](http://wearnumi.com/cdn/shop/files/the-signature-undershirt-numi-32.jpg?v=1715721336&width=1200)
!["#color_TRUFFLE | Ashleigh is 5’11” and wears a size L](http://wearnumi.com/cdn/shop/files/Truffle-SignatureFront-PDP.jpg?v=1715721336&width=1200)
!["#color_TRUFFLE | Ashleigh is 5’11” and wears a size L](http://wearnumi.com/cdn/shop/files/Truffle-SignatureBack-PDP.jpg?v=1715721336&width=1200)
!["#color_BLUSH| Emi is 5'7.5" and wears a size S](http://wearnumi.com/cdn/shop/files/Blush-Signature-Front2.jpg?v=1715721336&width=1200)
!["#color_BLUSH| Emi is 5'7.5" and wears a size S](http://wearnumi.com/cdn/shop/files/Blush-Signature-Back.jpg?v=1715721336&width=1200)
!["#color_CLOUD BLUE | Alex is 5'7" and was wears a size small](http://wearnumi.com/cdn/shop/files/CloudBlue-Signature-Front.jpg?v=1715721536&width=1200)
!["#color_CLOUD BLUE | Alex is 5'7" and was wears a size small](http://wearnumi.com/cdn/shop/files/CloudBlue-Signature-Back.jpg?v=1714050933&width=1200)
!["#color_NAVY | Alex is 5'7" and was wears a size small](http://wearnumi.com/cdn/shop/files/Navy-Signature-Front.jpg?v=1716839155&width=1200)
!["#color_NAVY | Alex is 5'7" and was wears a size small](http://wearnumi.com/cdn/shop/files/Navy-Signature-Side.jpg?v=1716839155&width=1200)
!["#color_NAVY | Alex is 5'7" and was wears a size small](http://wearnumi.com/cdn/shop/files/Navy-Signature-Back.jpg?v=1716839155&width=1200)
The Signature Undershirt
- Size Chart
- How to Measure
-
IN CM
Size
Classic
Limited Edition
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.
Choose from pre-selected bundles here.
![Sweat](https://cdn.shopify.com/s/files/1/0222/7028/files/StopsSweat-100x100.png?v=1695254696)
STOPS SWEAT STAINS
![Sweat](https://cdn.shopify.com/s/files/1/0222/7028/files/AbsorbsMoisture-100x100.png?v=1695254643)
ABSORBS MOISTURE & ODOR
![Sweat](https://cdn.shopify.com/s/files/1/0222/7028/files/Lightweight-100x100.png?v=1695254754)
LIGHTWEIGHT & BREATHABLE
![Sweat](https://cdn.shopify.com/s/files/1/0222/7028/files/4WayStretch-100x100.png?v=1695254716)
4-WAY STRETCH
![FitsTrueToSize-100x100.png__PID:7ca3a884-dc8b-499c-b177-0dfb3d5d5c6c](https://cdn.shopify.com/s/files/1/0222/7028/files/FitsTrueToSize-100x100.png?v=1703260891)
FITS TRUE TO SIZE
Find Your Perfect Styles
Buy 3, Get 15% off.
Discount code automatically applied at checkout.
![numi1282-Cropped.jpg__PID:dcb764f5-9fdc-48ca-940a-2ae922184b8c](https://cdn.shopify.com/s/files/1/0222/7028/files/numi1282-Cropped_500x.jpg?v=1712604002)
![Untitled design (21).jpg__PID:8fa6bc6a-272e-43c2-a300-6c5363f8a517](https://cdn.shopify.com/s/files/1/0222/7028/files/Untitled_design_21_113x.jpg?v=1700595754)
The Crop
Perfect for reducing bulk around your mid-section, especially when wearing high-waisted bottoms.
LEARN MORE
![Untitled design (17).jpg__PID:de1813ac-5b0a-435d-a071-816d61a60ef8](https://cdn.shopify.com/s/files/1/0222/7028/files/Untitled_design_17_1248f650-5c1d-49d1-9b42-fa1b66b43035_113x.jpg?v=1700595976)
The Square Neck
Designed with cap sleeves to seamlessly layer under all your shorter sleeved blouses. Features a flattering square neckline.
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![Untitled design (19).jpg__PID:936197da-cfee-48c1-8f92-3e4d0215deee](https://cdn.shopify.com/s/files/1/0222/7028/files/Untitled_design_19_c37c5472-197a-4e7a-86e0-142baead67b1_113x.jpg?v=1700596012)
The Three Quarter
Classic fit with sleeves hitting just below the elbow. It features a reversible neckline for added versatility.
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![Untitled design (18).jpg__PID:97dacfee-18c1-4f92-be4d-0215deee434a](https://cdn.shopify.com/s/files/1/0222/7028/files/Untitled_design_18_720609ff-994a-4664-aa14-3d6577f74bb6_113x.jpg?v=1700596017)
The Signature
Our #1 best seller is the ultimate base-layer for every outfit. No more sweat-stains or deodorant marks.
LEARN MORE
As Featured In
![Numi](http://wearnumi.com/cdn/shop/files/1_c0b4535d-95e9-4440-b503-c3a7d554f0d3.png?v=1684247676&width=450)
![Numi](http://wearnumi.com/cdn/shop/files/2_351fefab-34c7-41e9-a244-b1109796e1c6.png?v=1684247714&width=450)
![Numi](http://wearnumi.com/cdn/shop/files/Good_Morning_America_2021_logo_50b9bf43-3b5f-4605-a553-b916737a134c.png?v=1693321150&width=450)
![Numi](http://wearnumi.com/cdn/shop/files/4_4b5b823d-c1ae-48f7-ad78-2144440b11d9.png?v=1684247749&width=450)
![Numi](http://wearnumi.com/cdn/shop/files/5_052bcd83-0499-4e8d-8831-207ca02996c4.png?v=1684247767&width=450)
![Numi](http://wearnumi.com/cdn/shop/files/6_adf117b1-5262-42d8-b683-3edc1ccd27b4.png?v=1684247787&width=450)
FAQs
Women need sweat-proof undershirts to prevent visible sweat stains on their clothing and to stay dry and confident throughout the day. It can also help prolong the life of outerwear by reducing the need for frequent washing.
Our sweat-proof undershirts were created to be the perfect base-layer for day-to-day dressing. They feature our innovative Contemporary Cotton underarm shield, designed to wick and absorb moisture to prevent sweat stains from showing on your clothes. With the body made from a breathable TENCEL™ fabric, our undershirts also help to regulate your body temperature, ensuring all-day comfort.
We recommend using the size guide (featured on every product page) to determine the best size for you.
Each size guide features a sizing chart and instructions on how-to-measure the item. Generally, we recommend ordering our Essential Undershirt collection in your regular size for the perfect, snug fit. If you prefer a more relaxed fit, we recommend sizing up. If you’re still unsure about sizing, send us an email at customercare@wearnumi.com.
Absolutely! All our undershirts are machine-washable and dryer safe. Simply wash them cold and with like colors.