Undershirt Buying Guide: How to Choose the Right Undershirt

What started as standard-issue Navy wear has morphed into a men’s wardrobe staple. Undershirts provide an extra layer of warmth, conceal chest hair, block sweat and protect your clothes. If you wear dress shirts and suits, they must be protected from sweat, stains and odor, even through all-day wear.

But not all men's undershirts hold up to the test. There are a lot of cheap knockoffs out there that won’t protect your clothes against heavy sweating. Today, we’ll talk about how to choose an undershirt.

Learn more: Why, When and How to Wear an Undershirt

Gauge the Undershirt’s Quality

It’s easy to get duped when shopping for undershirts, especially online. For example, manufacturers have tricks to make garments look nice on screen while they unravel after a single use in real life.

How can you judge a quality undershirt from a cheaply made one? Here are six tips to help you separate the heroes from the zeroes.


An undershirt should feel soft on your skin — even if the cotton is thick or stiff. Softness often means the material consists of long fibers that will likely hold up over time.


Pilling happens when yarn fibers break or loosen or when exposed ends tangle, leaving small fluffy balls on the surface. Signs of pilling usually aren’t apparent until after a few wears, so it's best to forego the shirt altogether if you see any pills at first glance.

Although most fabrics are prone to pilling, high-quality undershirts won't pill as quickly.


Gauge the thickness of the fabric by holding up your shirt to a light source. The shirt likely won’t last too long if you can see through it.


Cotton undershirts spun from long, thin fibers won’t separate when gently pulling on the seams, as they have a consistent pattern and stitching. If you spot gaps between stitches or thread size differences, the shirt is probably doomed to a short lifespan.


Quality cotton shirts should bounce back to their natural state after scrunching them in your hand. If your shirt stays wrinkled, it’s a telltale sign it’s not high-quality cotton.


Loose threads or uneven seams signal the shirt was made from shorter fibers or poorly constructed and probably won’t stand the test of time.

Choose the Right Material

When it comes to high-quality undershirts, natural fibers like cotton and rayon from bamboo are superior to synthetic materials like polyester and nylon – but that doesn’t mean every cotton tee is a good choice. Cotton’s quality depends on the length of the fibers. Long-fiber cotton blends include Pima, SUPIMA® and Egyptian cotton, combed cotton, jersey, modal and rayon.

Shirts made with long fiber cotton help your clothing:

  • Breathe better. Longer fibers can be spun into finer yarn and are more tightly bound. As a result, you eliminate potential heat-retaining air pockets between threads, helping you feel cooler throughout the day.
  • Hold up longer. Tighter bonds also result in a stronger, more durable shirt.
  • Feel softer. Long cotton fibers create softer yarn than shorter fibers. The fibers can be spun into yarn with fewer stray ends sticking out, eliminating the itchy, scratchy feeling you've probably experienced from poorly made cotton shirts.


Synthetic fibers don’t have an entirely bad rap. Blending a small percentage of synthetic fiber with natural fibers improves fit, adds stretch and elasticity and ensures the shirt retains its shape after washing.

Natural fibers are:

  • More expensive than synthetic fibers
  • Not stain-resistant
  • Not water-resistant
  • Biodegradable
  • Not recyclable

Synthetic fibers are:

  • Cheaper than natural fibers
  • More stain-resistant
  • Can be water-resistant
  • Non-biodegradable
  • Recyclable

Determine Your Size

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.

Find the Right Fit

After you determine your size, you need to identify the proper fit. Traditional undershirts are close-fitting to the body, with smaller armholes so they invisibly (and comfortably) fit under clothes. A slim-fit undershirt is a good alternative if you wear more form-fitting clothes.

Pro tip: Choose tagless undershirts to eliminate unsightly bunching and itchiness.

What Style is Best?

Crewneck, v-neck or deep v-neck – which is best? As with many things, it depends. Think about what shirts you usually wear and what kind of look you prefer.


Crewneck undershirts offer the “traditional” undershirt look and can be worn with just about anything. However, the collar on crewneck shirts is often seen beneath open-collared dress shirts, t-shirts and flannel shirts.


If you stick to outer shirts with high necklines in fear of your undershirt peeking out, we recommend trying a v-neck or deep v-neckline. With these styles, no shirt is off-limits.


You should also consider the length of your undershirt. If you sport mostly casual, untucked shirts, buy shorter undershirts. T-shirts that hit you at or an inch above the hips will stay perfectly hidden.

If you always tuck in your outer shirts, get longer undershirts that fall at or slightly below the top of your pants inseam. The added length will help undershirts stay tucked even when you raise your arms.

How to Find the Right Thompson Tee Sweat Proof Shirt for Your Needs

Does Color Matter?

In a word, yes. Don’t wear a white undershirt beneath a white dress shirt. Because dress shirts are sheerer than t-shirts, white undergarments show through.

A good rule of thumb is to wear a black undershirt if your outer layer is a dark color (like black, navy blue, maroon, army green or charcoal gray). Try a beige or neutral undershirt if you’re wearing white or a lighter pastel color.

Thompson Tees are available in seven colors for men.

Choose the Right Undershirt: Thompson Tee

Thompson Tee’s sweat proof undershirts are made from 100% premium combed cotton and rayon from bamboo, so they're breathable, comfortable and durable enough to last a year with heavy use. Armed with Hydroshield®, our patented underarm sweat shields, Thompson Tees completely block moisture from seeping through your clothes and ruining expensive dress shirts.

With more than one million shirts sold worldwide, Thompson Tees truly are the best men's undershirt — whether you sweat heavily or not. Try one risk-free today!