The Thompson Tee undershirt has patented sweat-guard technology under the arms, but you wouldn't know it just by looking at it or trying it on because of the unobtrusive armpit pads. These pads absorb underarm sweat in layers, helping you avoid yellow stains and wet marks. With more than 700 five-star reviews, customers confirm that it really works. You can get the shirt in white, black, or heather gray — and also in a V-neck style. Most versions are made of 100 percent cotton, except for the heather which is 90/10 polyester.

It's ideal for wearing underneath a dress shirt, but it can also be worn solo since the arm pads are not too noticeable. Best yet, even if you've worn it, sweated into it, and it's just not the right fit, you can return it within 30 days of purchase. However, while these are long-lasting and offer extra protection not found in your average T-shirt, they're not the cheapest shirt around.

Fans say: "In the right conditions, I can easily sweat through an undershirt, a dress shirt, and into the inner lining of a suit jacket. But, wearing this Thompson Tee the other night was shocking.... Although I knew I was sweating, none of it showed through any of the shirts I wore. Undressing later in the evening, the only thing that was wet was the pad on the inside of the Thompson Tee itself; the outside of the Tee was 100% dry."

For the most underarm sweat protection you can get, Ejis offers thick arm pads in a modal-cotton fabric the brand says is bacteria-resistant and 50 percent more absorbent than cotton alone.

While the underarm pads might be a little too noticeable to wear this design on its own, it's great for under shirts. These tend to run small so consider sizing up but even if you get the wrong size, there's a 45-day return policy.

Fans say: "Ordered for son who lives in a very hot humid climate, sweat stains ruined all his clothing... truly prevents stains on his outer shirt and that the shirts are thin and comfortable to wear as an undershirt. Very different than just a white [T-shirt] purchased from local store."

Bamboo rayon has become a favorite for its silky feel and how absorbent it is. In fact, it can be up to 60 percent more absorbent than cotton. It's also hypoallergenic and antibacterial, making it a great undershirt material that's also great for the environment since it is biodegradable and comes from fast and easy to grow bamboo. These 95 percent bamboo rayon shirts (with 5 percent spandex) are breathable and naturally fight odor. The crewnecks come in black or white and at less than $10 a piece, a great price for quality undershirts.

Fans say: "The material is very comfortable and helps with reducing sweat/odor better than cotton undershirts."

Those looking for just a little help with sweat will find that this six-pack of shirts from Amazon Essentials has you covered for less than $4 each. Tagless and 100 percent cotton for extra comfort, they're a medium thickness suitable for under button-ups and to wear alone. Available in white and black V-necks, as well as a crewneck version, they've gotten hundreds of five-star ratings for being a great value.

Fans say: "My husband goes through t-shirts like no one's business. He sweats a lot and deodorant ends up staining his shirts in the underarm area, so we have to toss the shirts once that happens... We needed to find some shirts that are affordable and comfortable. These are great. They work as undershirts, but they also are good as regular shirts to wear out."

If chest sweat is more your concern than underarm sweat, consider these sleeveless undershirts made of 95 percent eco-friendly bamboo rayon and 5 percent spandex. Available in black, gray, and white, these three-packs are light and breathable, while also effectively absorbing sweat thanks to the bamboo. Plus, they won't leave a line on your bicep underneath a button-up.

With a 4.5-star overall rating after more than 400 reviews, they're a fan favorite that's also available in a cotton-spandex blend and 100 percent ribbed cotton.

Fans say: "These are very comfortable especially in the hot summers in the South. The material allows for sweat to be removed and feels dry much quicker than regular cotton undershirts. They were so good that I went back and got another two packs of three, they don't shrink either like cotton ones do!"

RibbedTee's extra-light, vintage-inspired tees are made of a cotton-polyester blend that falls smoothly on the body making it a great undershirt. They're so comfortable, the editors of Esquire and Salon.com even vouched for them. The yarns are designed with moisture absorption in mind making these tees great to wear under something else. A little thinner than most, they might not be the best option for wearing solo, though.

Fans say: "Very thin but very comfortable and the collars lay flat and stay tight. What a novel idea for an undershirt! Keep it up!"

Mic may receive a portion of sales from products purchased from this article, which was created independently from Mic's editorial and sales departments.