Why UnderFit?

1. Quality

2. Comfort

3. Value

We’ve been perfecting the Underfit™ undershirts since 2012. The proprietary Modal® fabric offers exceptional softness, superb temperature regulation (breath- ability), advanced moisture absorption and odor resistance.

These qualities provide the ideal fabric for an undershirt that will keep you cool and comfortable when the heat goes up.

Our fabric is odor resistant. Moisture wicking technology limits moisture; which is needed to breed odor causing bacteria.

With over a decade and a half of perfecting the undershirt fit, we have created a size chart that ensures your best fit. Even if you think you are a medium, we may say a large. Trust us, we want you to have the best fit. We have even added three extra inches of length so your shirt stays tucked all day, guaranteed.

Modal® has an extremely high tensile strength, which means it’s hard to tear. UnderFit™ shirts keep their shape and great fit for years.

The UnderFit Difference

We already know our shirts are different, so we’re trying to make a difference, too!

5% of our profits go directly to one of our affiliated causes and you get to choose which one:


The ramifications of war aren’t just left on the battlefield; they’re silently brought back home when our soldiers return. We’ve teamed up with the Veterans Support Foundation to help our veterans adjust to life back at home, with housing, rehabilitation, and access to a multitude of veteran-centric non-profits.

Visit the Veterans Support Foundation

Prostate Cancer

1 in 7 men will be diagnosed with prostate cancer within their lifetime, and it’s the third leading cause of cancer death in American men. We’ve teamed up with the Prostate Cancer Foundation and share their mission of finding a cure to this devastating disease.

Visit the Prostate Cancer Foundation

Clean Water

783 million people don’t have access to clean water, and almost 2.5 billion people don’t even have water good enough for sanitation and cleaning. It’s easy to forget that the water that comes out of our taps isn’t available to most of the planet, so we’re aligning with The Thirst Project to give billions of people access to our species’ most valuable resource: clean water.

Visit the Thirst Project