Frequently Asked Questions

Find answers to common questions about Thompson Tee's innovative sweat proof undershirts, shipping and returns, heavy sweating and more in our comprehensive list of FAQs.

Product & Care FAQs

How is the Thompson Tee different from other "sweat proof" shirts?

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The Thompson Tee is the original sweat proof undershirt.

Our Hydro-Shield® sweat proof technology completely absorbs and evaporates sweat while maintaining breathability. It's the only undershirt backed by a patent from the U.S. Patent and Trademark Office. Although others might say "sweat proof," no undershirt can protect you like the proven Thompson Tee, and no other shirt has patented technology to back up such a claim.

Here are the features that make our sweat proof undershirts unique:

  • Proprietary layering and stitching use reverse osmosis to pull sweat away from your skin, leaving you feeling cool and dry.
  • Sweat proof technology won’t wash out or lose effectiveness over time.
  • Underarm barriers include a center seam design for a sleek, smooth fit. The shirt doesn’t bunch under your clothing or show sweat through your outer layers.
  • Hydro-Shield® pads are fully integrated into the overall shirt design and never need adjusting.

Original Fit vs. Slim Fit: Which one is right for me?

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The shirt and size you choose will ultimately depend on your fit and style preferences.

Original Fit shirts are made from 100% premium combed cotton and provide more breathing room for those who prefer a looser undershirt. If you're looking for the most sweat protection but like the fit of a typical T-shirt, try a size up in the Original Fit shirts.

Both our Men’s and Women’s Slim Fit shirts are made with rayon from bamboo. They are designed to fit snugly, so they’re more discreet underneath your clothing.

Either way, both options come with our proprietary Hydro-Shield® Sweat Proof Technology, backed by our Sweat Proof Guarantee!

Check out our Buyer’s Guide to learn more about choosing the right Thompson Tee size and style.

Is Thompson Tee’s underarm barrier really sweat proof?

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Yes! We didn't just call it "sweat proof" – we earned it! The Thompson Tee is the only patented proprietary design featuring clinical-grade sweat proof material that completely blocks moisture from passing through. Other shirts may advertise "sweat proof" but don’t hold moisture well, typically consisting of two cotton layers often treated with chemicals that could wash out over time.

The benefits of our sweat proof technology are native properties, so the shirt will never lose its effectiveness. That's why every Thompson Tee with Hydro-Shield® Sweat Proof Technology comes with a Sweat Proof Guarantee. We guarantee that your underarm sweat won’t penetrate the sweat proof barrier — or your money back!

How does the sweat proof underarm barrier compare to sweat pads?

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While underarm sweat pads and sweat shields may absorb some sweat, they do not allow moisture to evaporate. So throughout the day, armpit pads can lose their stickiness or become heavy and bulky beneath your shirt.

Unlike sweat shields, garment guards and sweat pads, Thompson Tee's sweat proof barrier is the only patented sweat proof technology available. By trapping sweat and releasing it through evaporation, your sweat won't show through your outerwear. Plus, you won't have to worry about adjusting your sweat pad or changing it out throughout the day.

Can I machine wash and dry the undershirt? (Care Instructions)

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Yes! Like other undershirts, the Thompson Tee with Hydro-Shield® Sweat Proof Technology can be machine washed in cold or warm water and dried in medium (or lower) heat.

We HIGHLY recommend turning the garment inside out when washing AND drying to ensure the fabric exposed to the skin and sweat is thoroughly cleaned and dried. You can also hang our undershirt to dry in the sun. Please see your neck label for complete care instructions.

Please do not do any of the following, as they will compromise Thompson Tee’s sweat proof technology:

  • Please do NOT use bleach, bleach alternatives, non-chlorine bleach or any detergent with bleach byproducts.
  • Please do NOT dry clean.
  • Please do NOT iron.

My Thompson Tee is starting to smell. How do I stop the odor?

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Everyone sweats, and sweat smells. To prevent odor from sticking around, turn the shirt inside out when washing/drying to ensure the part exposed to your skin is thoroughly cleaned and dried.

Try pretreating by applying non-bleach detergent directly to the inside of the shirt’s underarm area (the area touching the skin) before washing. You can also periodically wash shirts in hot water to improve cleaning. Repeat the steps above for tough odors, using distilled white vinegar to pretreat the underarm area. Don't worry – the vinegar smell will wash out.

Will my Thompson Tee shrink after laundering?

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TWe build anticipated shrinkage into each shirt we create, so your shirt should shrink to the designated size on our size chart. You can expect minimal shrinkage when compared to traditional undershirts.

Original Fit: We use 100% Premium Ring Spun Combed Cotton (exclusive of Thompson Tee Hydro-Shield®), so you can expect only about a 5% shrinkage compared to traditional undergarments, which may shrink 10%-15%.

Slim Fit: Our Slim Fit shirts are made of 95% premium rayon from bamboo and 5% spandex. You can expect about 8% shrinkage compared to traditional undergarments, which may shrink 10%-15%.

Can I wear the undershirt right out of the package?

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We recommend washing all garments before wearing them for the first time, especially undergarments. This will further tighten the fibers, making them softer and more comfortable. That said, we use such high-quality, ultra-soft material that our undershirts are comfortable right out of the package.

Can I sleep overnight wearing a Thompson Tee?

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We do not recommend sleeping overnight in the Thompson Tee as underarm sweat is generally not a concern during sleep. The Thompson Tee is a functional garment, and although there is no inherent problem with wearing it overnight, we advise against doing so to optimize its functionality, minimize regular wear and tear and prolong the overall durability of the shirt.

How does the Thompson Tee Hydro-Shield® sweat proof barrier work?

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The Thompson Tee Hydro-Shield® sweat proof barrier combines innovative design and advanced materials. Our shirts feature a patented proprietary layering system of clinical-grade fabric that creates air pockets and facilitates reverse osmosis, blocking moisture from passing through. This barrier acts as a shield, preventing underarm sweat from reaching your shirt's outer layer.

What is the underarm barrier made of?

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Our integrated sweat proof barrier includes a stitching and layer system composed of a looped-knit fabric that soaks up sweat and an ultra-thin medical-grade film that keeps it from leaking through.

How does Thompson Tee differ from wearing a typical undershirt beneath my dress shirt?

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The Thompson Tee actively wicks away moisture, ensuring you stay dry and comfortable throughout the day. Unlike regular undershirts, the Thompson Tee is designed to be discreet and virtually invisible under your clothing. Plus, it’s crafted with high-quality materials, making it more durable than a typical undershirt.

I sweat heavily. Will the Thompson Tee sweat barrier work for me?

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Thompson Tee’s integrated underarm sweat barrier is guaranteed to block 100% of underarm sweat or your money back!

What color options does Thompson Tee offer?

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Men’s Original Fit undershirts are available in white, black, heather grey, olive drab green, navy, coyote brown and tan 499.

Women’s Original Fit undershirts are available in white, olive drab green, navy, coyote brown and tan 499.

Men’s Slim Fit Crewneck undershirts are available in white and black.

Men’s Slim Fit V-Neck undershirts are available in white, black, heather grey and beige.

Women’s Slim Fit Scoop Neck undershirts are available in white, black and beige.

Women’s Slim Fit Deep V-Neck undershirts are available in white, black, heather and beige.

What neckline options does Thompson Tee offer?

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Men's Thompson Tees come in crewneck, V-neck and deep V-neck necklines.

Women's Thompson Tees are available in crewneck, scoop neck and deep v-necklines.

Can I easily tuck in the Thompson Tee?

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Yes! We designed our shirts with extra length to ensure they stay tucked in without bunching.

What do other customers say about Thompson Tees?

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Check out our customer reviews of the Thompson Tee here!

Will I feel gross or hot wearing the Thompson Tee beneath my shirt?

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No, not at all. Once the sweat proof barriers soak up your sweat, our proprietary layering system creates air pockets that facilitate reverse osmosis, releasing your sweat as vapor and leaving you feeling dry and comfortable.

Is the Thompson Tee a natural solution for underarm sweat protection?

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Yes! While most moisture-wicking materials are treated with harsh chemicals that wear off after a couple of washes, we make Thompson Tees with natural rayon from bamboo and premium combed cotton. Not only do they last longer than other undershirts, but their sweat-absorbing abilities also endure well beyond a handful of washes.

Can I easily tuck in the Thompson Tee?

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Yes! We designed our shirts with extra length to ensure they stay tucked in without bunching.

What size should I buy?

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Here’s how to measure for the best undershirt fit:

  • Measure around the fullest part of your chest, keeping the tape measure under your armpits and around (not above or below) your shoulder blades. For accurate results, wear an undershirt while measuring.
  • Consult your undershirt manufacturer’s sizing guide. If you’re between sizes, pick the next largest size for the most comfortable fit.

See our Thompson Tee Buyer’s Guide for our undershirt sizing charts for men and women.

How durable are Thompson Tees?

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Thompson Tees are highly durable and withstand regular use and washing. The shirts are crafted using high-quality materials and construction techniques to ensure longevity. The sweat proof barrier, made from clinical-grade fabric, retains its effectiveness even after multiple uses and washes.

By following proper care instructions, you can maintain Thompson Tees' durability and sweat protection properties over an extended period. While the exact lifespan may vary depending on individual usage and care, customers generally find our sweat proof undershirts long-lasting and reliable

Can you feel liquid build up in the arms? If you squeeze it, does liquid squish out?

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No, liquid does not squish out, and you cannot feel liquid build up. Sweat escapes as vapor, leaving you feeling dry and comfortable – with no embarrassing wet marks!

Can you wear Thompson Tee under another shirt?

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Yes! Our undershirts are designed to be worn under other shirts. However, if you’re looking for a sleek look (or want to wear an undershirt beneath a regular t-shirt), consider one of our slim fit undershirts. Our slim fit shirts skim your body for a fitted, subtle look.

Can you see the seams on the sleeve through a white dress shirt?

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Thompson Tees are designed with minimal seams to reduce visibility and enhance comfort. However, depending on the fit and thickness of the white dress shirt worn over the Thompson Tee, there is a possibility that faint seam lines may be slightly visible. The visibility of the seams can also depend on the lighting conditions and the specific fabric of the dress shirt.

To minimize the visibility of seams, we recommended choosing a well-fitted dress shirt that is not overly tight. Additionally, selecting a Thompson Tee that closely matches the color of the dress shirt can further help reduce the visibility of any potential seam lines.

I am typically between sizes. What should I choose?

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If you're unsure about sizing, go one size larger to allow for shrinkage.

Do Thompson Tees prevent sweat odor?

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Our sweat proof undershirts are not designed to control odor. However, if you're looking for a comfortable and effective way to combat underarm odor, look no further than Thompson Tee’s Anti Odor T-shirts. Featuring our advanced Odor Shield™ technology, these shirts trap and neutralize skin bacteria, eliminating 99.9% of odor for all-day freshness and confidence.

Return & Exchange

What is your return/exchange policy?

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We’re so confident you’ll love your no-sweat Thompson Tee that we guarantee it 100%! If you are unsatisfied for any reason, you may return the item for a full refund within 30 days of the order date. Your return shipping is free.

Do you cover return shipping costs?

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We offer free return shipping for domestic orders under our 30-day guarantee. Please fill out the return form to submit a return request, and a label will be provided to you.

When will I receive my refund?

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Please allow 5-10 business days to process your return once received. Any credits or charges will be issued to the original form of payment unless otherwise indicated by Customer Service.

What if my shirt is faulty or damaged in transit?

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Please let us know via the return form. Once we receive the form, we will initiate a claim with the shipping carrier.

What if I have a concern about my order?

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Please get in touch with us about any order concerns via phone, chat or email. Our customer service team is available Monday - Friday from 8:00 AM - 5:00 PM PST.

How can I return Undershirt Packs?

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Please note that individual items from a pack cannot be returned; you must include all items for a refund.

I ordered the wrong size/fit; how can I receive the correct one?

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Please call Thompson Tee customer support at (866) 261-5218, email us at, or fill out a form on our Contact Us page, and we’ll get right back to you.

Shipping & Delivery FAQs

What shipping methods do you offer?

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For your convenience, we offer three shipping options:

  • FREE Standard Shipping on orders $50+: Delivered within 3-5 business days
  • Standard Shipping (no minimum purchase required): Delivered within 3-5 business days, $3.99-$9.99
  • Standard Overnight: Delivered within 2 business days (must order by 11 am PST, Mon-Fri), $25-$40

Please visit our Shipping and Deliveries page for more information.

Do you cover return shipping costs?

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Absolutely! Our domestic shipping rates apply to both Alaska and Hawaii.

Do you ship internationally?

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Yes! Please see our Shipping and Deliveries page for a complete list of countries we ship to, along with our international shipping disclaimer.

How will my order ship?

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We’ve optimized your shipping options with USPS (United States Postal Service) and FedEx to ensure you get the most efficient and cost-effective shipping methods.

When will my Thompson Tees ship?

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If we receive your order before 12:00 pm, we do same-day shipments on business days.

What should I do if my package is lost or stolen?

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Please contact the mail carrier for further instructions.

How much does shipping cost?

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Free shipping is available for all domestic orders over $50. Standard USPS and FedEx shipping rates apply to all international orders. Check out our Shipping and Deliveries page for more information.

Will my package be charged customs fees?

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Customers are responsible for all customs fees, taxes, and brokerage charges. While many orders make it through customs without issues, the customs agency in your country may require you to pay fees before receiving your package.

You are responsible for checking with your country's Customs Office to verify any fees, as we cannot provide the exact amount of the charges. By completing your order, you agree to pay all applicable fees. Check out our Shipping and Deliveries page for more information.

Can I track my order delivery?

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Yes! We provide tracking numbers in your order confirmation email.

Heavy Sweating FAQs

Why do we sweat?

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Sweating is a natural response to regulate body temperature. When our bodies sense an increase in temperature, whether due to physical exertion, heat or emotional stress, sweat glands produce sweat. As sweat evaporates from our skin, it helps to cool the body down, maintaining a stable internal temperature.

Read more about why we sweat.

What are some common types of sweating problems?

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Almost everyone sweats. But sometimes sweat can be extreme and difficult to manage. Primary (localized) hyperhidrosis is a sweating condition in which a person perspires excessively from one particular area, such as the armpits, hands or feet.

Secondary hyperhidrosis is a sweating condition in which a person sweats excessively all over the body, not just one particular area. Unlike localized hyperhidrosis, secondary hyperhidrosis is not a condition but a side effect of another medical condition or medication.

Beyond hyperhidrosis, other sweating problems, such as night sweats and situational sweating, exist. Learn more about the different types of sweating problems on our Sweat 101 page.

What is hyperhidrosis?

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Hyperhidrosis is sweating beyond the physiological necessity required to regulate body temperature. It is a significant burden on quality of life from a psychological, emotional and social perspective.

People of all ages get hyperhidrosis. For many people, hyperhidrosis begins when they are a child or teen. Whether you live in a cold or warm climate, you can have hyperhidrosis.

How do I know if I have axillary hyperhidrosis (excessive underarm sweating)?

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People who have axillary hyperhidrosis sweat profusely in their armpits without warning. They often sweat heavily even while sitting or in cold temperatures. Axillary hyperhidrosis is genetic, so if someone in your family also suffers from excessive underarm sweating, you are more likely to inherit the condition. Heavy underarm sweating is still a daily concern for a larger population who may not have the clinical diagnosis.

Check out Your Guide to Armpit Sweat for more information on heavy underarm sweating and how it differs from axillary hyperhidrosis.

What are some solutions for axillary hyperhidrosis?

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Excessive armpit sweating is incurable, but some solutions will reduce underarm sweat. Heavy-duty or clinical antiperspirants can be effective, but for many people with hyperhidrosis, antiperspirants alone won't stop them from pitting out.

Unfortunately, many sweating solutions on the market are invasive, expensive, unproven or untested. Some solutions include underarm surgery, laser treatments and BOTOX. Due to the potentially irreversible side effects, conducting thorough research and speaking to a dermatologist before opting for any invasive treatments is essential.

Learn more about Thompson Tee co-founder Randy Choi's experience with ETS surgery for hyperhidrosis.

How do I stop nervous sweating or stress sweating?

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Stress and nerves are unavoidable facts of life for even the most confident people. Sweating is an evolutionary byproduct of these emotions.

Sweating under stress or worrying about an upcoming event interferes with daily life. Wearing a Thompson Tee can help curb the effects of nervous or stress sweating and the vicious sweat cycle that follows.

For more tips for stopping stress or nervous sweating, check out our page on stress sweating.

What are the best undershirts and materials for sweat?

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Everyone sweats for different reasons. Whether you sweat bullets when exercising or in the boardroom, wearing a sweat proof shirt can save the day.

Because Thompson Tee's sweat proof barrier allows sweat to evaporate (unlike most cotton undershirts that lock it in), it is effective for people with axillary hyperhidrosis, those who sweat heavily on occasion and even athletes who work up a sweat at the gym or on the field.

To learn more about sweat-blocking materials on the market and which may be right for you, check out our page on the Best Undershirts for Sweat.

What causes yellow stains, and how can I prevent them?

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Heavy underarm sweating and yellow stains go hand-in-hand. But did you know sweat itself isn't the cause of yellowing? Yellow stains occur when the proteins in your sweat react with aluminum and other chemicals in your antiperspirant.

When these compounds mix with bacteria on the skin, they create yellow stains that quickly ruin your dress shirts and undershirts. By switching to deodorant and cutting back on antiperspirant, you can prevent yellow stains from forming. Learn more by reading The Science Behind Armpit Stains & How to Stop Them.

other FAQs

What's your return policy?

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Your purchase is 100% RISK-FREE! We gladly offer free returns on all opened or used Thompson Tees up to 30 days from the purchase date, so feel free to wear and wash them! Learn more on our Return Policy page.

Who can I contact with questions about my order?

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Your complete satisfaction is our top priority – contact us anytime!

Please send us an email with your concerns to

Where can I buy a Thompson Tee?

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You can buy a Thompson Tee on our website, Amazon US, Amazon Canada and Amazon UK.

Does Thompson Tee offer a risk-free trial?

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Yes! We gladly offer free returns on all opened or used Thompson Tees up to 30 days from the purchase date. Feel free to wear it and wash it!

What types of payments do you accept?

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We accept credit cards, debit cards, PayPal, PayPal Pay Later, Amazon Pay and Afterpay.

What is Afterpay?

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Afterpay is a popular "buy now, pay later" service. It allows customers to make purchases and split the cost into interest-free installments over time rather than upfront. For more information, please visit Afterpay’s website.

Can I edit or cancel an order after it has been placed?

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We strive to process orders quickly, which means that once you place an order, changes may not be possible. However, if you need to modify or cancel an order, please call us at (866) 261-5218 as soon as possible. We'll be happy to assist you in any way we can.

Do you offer gift cards?

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Yes! We offer gift certificates via email in $25 increments up to $300. Recipients can redeem them exclusively on Buy one now on our Gift Certificates page.

Where can I get a discount code?

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Get 15% off your next purchase by subscribing to receive text message notifications from Thompson Tee! Text THOMPSON to +1 (833) 208-9588 to join. Visit our Discounts & Coupon Codes page to learn more.

Do you have an affiliate program?

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Yes! To register, visit our Affiliate Registration page.

Do you have a rewards program?

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Yes! As a Thompson Tee rewards member, you’ll earn points every time you shop. It is completely free to sign up. The more points you earn, the closer you are to acquiring exclusive rewards. Points are only awarded when shopping on the Thompson Tee website. Visit our Rewards page to register today.

When do out-of-stock products restock?

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Be the first to know about restock updates by subscribing to our newsletter or following us on social media!