Bestseller
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.
 
"#color_almond| Emi is 5'7.5" and wears a size S
Emi is 5'7.5" and wears a size S
"#color_almond| Emi is 5'7.5" and wears a size S
Emi is 5'7.5" and wears a size S
"#color_toffee| Tolu is 5'7.5" and wears a size M
Tolu is 5'7.5" and wears a size M
"#color_toffee| Tolu is 5'7.5" and wears a size M
Tolu is 5'7.5" and wears a size M
"#color_black| Siobhan is 5'8.5" and wears a size S
Siobhan is 5'8.5" and wears a size S
"#color_black| Siobhan is 5'8.5" and wears a size S
Siobhan is 5'8.5" and wears a size S
"#color_white| Siobhan is 5'8.5" and wears a size S
Siobhan is 5'8.5" and wears a size S
"#color_white| Siobhan is 5'8.5" and wears a size S
Siobhan is 5'8.5" and wears a size S
"#color_HEATHER GREY|Estyr is 5'9", wearing a size XS
Estyr is 5'9", wearing a size XS
"#color_HEATHER GREY|Estyr is 5'9", wearing a size XS
Estyr is 5'9", wearing a size XS
"#color_TRUFFLE | Ashleigh is 5’11” and wears a size L
Ashleigh is 5’11” and wears a size L
"#color_TRUFFLE | Ashleigh is 5’11” and wears a size L
Ashleigh is 5’11” and wears a size L
"#color_BLUSH| Emi is 5'7.5" and wears a size S
Emi is 5'7.5" and wears a size S
"#color_BLUSH| Emi is 5'7.5" and wears a size S
Emi is 5'7.5" and wears a size S
"#color_CLOUD BLUE | Alex is 5'7" and was wears a size small
Alex is 5'7" and was wears a size small
"#color_CLOUD BLUE | Alex is 5'7" and was wears a size small
Alex is 5'7" and was wears a size small
"#color_NAVY | Alex is 5'7" and was wears a size small
Alex is 5'7" and was wears a size small
"#color_NAVY | Alex is 5'7" and was wears a size small
Alex is 5'7" and was wears a size small
"#color_NAVY | Alex is 5'7" and was wears a size small
Alex is 5'7" and was wears a size small

The Signature Undershirt

Sale price$70.00
END OF SEASON SALE
Size:

Size

Color:ALMOND

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

STOPS SWEAT STAINS

Sweat

ABSORBS MOISTURE & ODOR

Sweat

LIGHTWEIGHT & BREATHABLE

Sweat

4-WAY STRETCH

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FITS TRUE TO SIZE

TECHNOLOGY

  • Absorbent Contemporary Cotton underarm shields that wick away sweat and odor
  • Guaranteed to stop 100% of sweat stains
  • Lightweight, 4-way stretch, comfortable and breathable
  • Unmatched luxury and softness of our staple fabric

STYLE

  • Reversible neckline: choose between scoop or crop neck
  • Seamless sleeves with a raw edge for an invisible look under outer layers
  • The ultimate essential base layer

Free Shipping & Easy Returns

Free shipping on U.S. and Canada orders over $150. 

Please allow up to 2-3 business days for processing before your order ships. More shipping info here.

Returns

Items purchased with a 0-19% discount are eligible for refund, within 30-days of the delivery date. Items purchased with a 20% discount or higher are eligible for exchange or store credit.

Gift cards are non-refundable, and items listed as  Last Chance and Final Sale are not eligible to be returned or exchanged, meaning that no returns, exchanges or refunds can be accommodated.

Find out more about our return policy here.  

Free Shipping & Easy Returns

Free shipping on U.S. and Canada orders over $150. 

Please allow up to 2-3 business days for processing before your order ships. More shipping info here.

Returns

Items purchased with a 0-19% discount are eligible for refund, within 30-days of the delivery date. Items purchased with a 20% discount or higher are eligible for exchange or store credit.

Gift cards are non-refundable, and items listed as  Last Chance and Final Sale are not eligible to be returned or exchanged, meaning that no returns, exchanges or refunds can be accommodated.

Find out more about our return policy here.  

30-Day Money Back Guarantee

We stand by the quality of our products. If you're not completely satisfied within 30 days of your purchase, contact us and we'll gladly refund your order. It's that simple.

30-Day Money Back Guarantee

We stand by the quality of our products. If you're not completely satisfied within 30 days of your purchase, contact us and we'll gladly refund your order. It's that simple.

Chat for Size Help

Use our chat icon at the bottom left corner to chat with a live agent or send us an e-mail at customer@wearnumi.com

Chat for Size Help

Use our chat icon at the bottom left corner to chat with a live agent or send us an e-mail at customer@wearnumi.com

Find Your Perfect Styles

Buy 3, Get 15% off.
Discount code automatically applied at checkout.

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The Crop 

Perfect for reducing bulk around your mid-section, especially when wearing high-waisted bottoms.

LEARN MORE 

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The Square Neck

Designed with cap sleeves to seamlessly layer under all your shorter sleeved blouses. Features a flattering square neckline.

LEARN MORE

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The Three Quarter 

Classic fit with sleeves hitting just below the elbow. It features a reversible neckline for added versatility.

LEARN MORE

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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
Numi
Numi
Numi
Numi
Numi

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.

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