Frequently Asked Questions

Did you know: Millions of men and women deal with excessive underarm sweating every day. But for some heavy sweaters, it qualifies as a medical condition.


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

The Thompson Tee is the original sweat proof undershirt.

It's the only undershirt backed by a patent from the U.S. Patent and Trademark Office for our Hydro-Shield sweat proof technology, which completely absorbs and blocks sweat while maintaining breathability. 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 a few of the features that make our sweat proof undershirts unique:

  • Proprietary layering and stitching system blocks sweat from seeping through your underarms.
  • Sweat proof technology won’t wash out or lose effectiveness over time.
  • Separate front and back panels to trap sweat effectively, minimize heat build-up and keep you feeling cool.
  • The underarm barriers are created with a center seam design for a sleek, smooth fit that doesn’t bunch under your clothing.

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

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

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

The Original Fit is made from 100% premium combed cotton and provides a little 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, you may want to try a size up in the Original Fit shirts.

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

For the complete guide to choosing the right Thompson Tee size and style for you, check out our blog here.

Is the underarm barrier really sweat proof?

YES - We didn't just call it "sweat proof." We earned it! The Thompson Tee is the only patented proprietary design that uses a clinical-grade sweat proof material that completely blocks moisture from passing through. Other shirts may advertise "sweat proof" but don’t hold moisture well. They typically consist of two cotton layers and are often treated with chemicals that could wash out over time. The benefits of our sweat proof technology are native properties, so the shirt will not lose its effectiveness over time. 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?

While armpit 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 due to sweat 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 for a new one throughout the day.

For more in-depth information on sweat pads and sweat shields, check out our page dedicated to the topic here.

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

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. It can also be hung to line dry in the sun as well. Please do NOT use any bleach, bleach alternatives, non-chlorine bleach or any bleach byproducts in the detergent, as this will compromise the sweat proof technology.

Please do NOT dry clean. The chemicals used when dry cleaning will compromise the sweat proof technology. Please do NOT iron, as the intense direct heat from the iron can compromise the sweat proof technology. Please see your neck label for complete care instructions as well.

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

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 underarm area (the area touching the skin) prior to washing. Also feel free to periodically wash the shirts with "hot" water to improve cleaning. For really tough odors, repeat the steps above, but use distilled white vinegar to pretreat the underarm area. Don't worry; the vinegar smell will wash out.

Will the undershirt shrink after laundering?

The anticipated shrinkage is built into each shirt we create, so the shirts 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: We use 95% Premium Rayon from Bamboo and 5% Spandex. You an expect about 8% shrinkage compared to traditional undergarments, which may shrink 10%-15%.

Can I wear the undershirt right out of the package?

We recommend washing all garments prior to wearing them for the first time, especially undergarments. This will further tighten the fibers, making it softer and more comfortable. However, we use such high-quality ultra soft material that you'll find our undershirts are very comfortable right out of the package.

Can I sleep overnight wearing the undershirt?

We do not recommend sleeping overnight in the Thompson Tee with Hydro-Shield Sweat Proof Technology, as underarm sweat usually is not an issue when asleep. The Thompson Tee is a functional garment, and although there is no problem sleeping in the shirt, we simply make the recommendation to maximize the utility and reduce normal wear and tear, extending the overall quality of the shirt.

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

Our proprietary layering system creates air pockets and facilitates reverse osmosis — releasing your sweat as vapor and leaving you feeling cool and dry.

What is the underarm barrier made of?

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?

We guarantee that your sweat will not break through our sweat-proof barrier! Check out this YouTube video for proof!

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

Thompson Tee’s integrated underarm sweat barrier is guaranteed to block 100% of underarm sweat or your money back. If you sweat through your Thompson Tee, refer to this resource.

What color options does Thompson Tee offer?

All men’s and women’s Original Fit Thompson Tees are available in white, black, heather grey and beige.

All men’s and women’s Slim Fit Thompson Tees are available in white and black.

What neckline options does Thompson Tee offer?

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

Women's Thompson Tees are currently only available in scoop neck.

Can I easily tuck in the Thompson Tee?

We designed our shirts with extra length to ensure they stay tucked in without bunching. Other undershirts like Kleinert’s and Sweatshield have extra length, but according to one reviewer, Thompson Tee's are even longer.

What do other customers say about Thompson Tees?

You can check out reviews of the Thompson Tee here!

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

No not at all. Once the sweat shields soak up your sweat, our proprietary layering system creates air pockets and facilitates reverse osmosis — releasing your sweat as vapor and leaving you feeling cool and dry.

Is the Thompson Tee a natural solution to underarm sweat?

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


Why do we sweat?

Early humans ran long distances in open areas. In order to survive in the equatorial sun, they needed to cool their brains. So they evolved an increased number of sweat glands for that purpose, which in turn permitted their brain size to expand.

Read more about why we sweat.

What are some common types of sweating problems?

Of course, everyone sweats. But sometimes sweat can be the side effect of a medical issue or a condition itself. 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 itself, but rather the side effect of another medical condition or medication.

Beyond hyperhidrosis, other sweating problems also exist, such as night sweats and situational sweating. Learn more about the different types of sweating problems here.

What is hyperhidrosis?

Hyperhidrosis is sweating beyond physiological necessity required for regulation of body temperature. It is a significant quality of life burden from a psychological, emotional, and social perspective. People of all races get hyperhidrosis. The excessive sweating can begin at any age. For many people, hyperhidrosis begins when they are a child or teen. Whether you live in a cold climate or a warm one, you can have hyperhidrosis.

Learn more about hyperhidrosis here.

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

People who suffer from axillary hyperhidrosis sweat profusely in their armpits without warning. Often, they sweat heavily throughout the day 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. For a larger population who may not have the clinical diagnosis, heavy underarm sweating is still a daily concern.

For more information on heavy underarm sweating and how it differs from axillary hyperhidrosis, check out our page on the topic here.

What are some solutions for axillary hyperhidrosis?

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

Unfortunately, many sweating solutions on the market are invasive, expensive, unproven, or worse, untested. Some solutions include underarm surgery, laser treatments and BOTOX. Due to the potentially irreversible side effects, it's important to conduct thorough research and speak to a dermatologist before opting for any invasive treatments.

For a complete list of solutions to axillary hyperhidrosis, read our blog post here. To learn more about Thompson Tee co-founder Randy Choi's experience with ETS surgery for hyperhidrosis, click here.

How do I stop nervous sweating or stress sweating?

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

Sweating under stress or when worrying over 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.

Want to learn more tips for stopping stress or nervous sweating? Check out our page on nervous sweating and stress sweating for more information.

What are the best undershirts and materials for sweat?

Everyone sweats for different reasons. Whether you sweat bullets when exercising or in the boardroom, you need a sweat proof shirt that can handle it.

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 topic here.

What causes yellow stains and how can I prevent them?

Heavy underarm sweating and yellow stains seem to go hand-in-hand. But did you know sweat itself isn't the cause of yellowing? The real source is the aluminum in your antiperspirant.

When these compounds mix with bacteria on the skin, they create those yellow stains that quickly ruin your dress shirts and undershirts. By switching to deodorant and cutting back on the use of antiperspirant, you can prevent yellow stains from forming. For more tips to avoid pitting out, check out our post here.


What's the Return policy?

Your purchase is 100% RISK FREE! We gladly offer free returns on all opened or used Thompson Tees up to 30 days from purchase date, so feel free to wear it and wash it! Click here for our complete Returns policy.

Who can I contact with questions about my order?

Please send us an email with your concerns to:

Your complete satisfaction is our top priority! Please feel free to contact us anytime!

How much does shipping cost?

Free shipping is available for all domestic orders over $50. Standard USPS and FedEx shipping rates apply to all international orders.

For more information on international shipping, check out our Shipping and Deliveries page.

Where can I buy a Thompson Tee?

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

Does Thompson Tee offer a risk-free trial?

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