UnderFit undershirts are cut longer and lightly hug your hips and below, to stay tucked in all day. Our fabric is ideal for undershirts due to its exceptional softness, advanced moisture absorption, odor resistance and superb breathability. If you want to remain less comfortable in your run-of-the-mill undershirt, by all means, DON’T buy an UnderFit.
Written by the business, not verified by us.
Is UnderFit legit?
UnderFit (underfit.com) has a 4.3 out of 5 rating on OK.one, based on 101 user reviews collected here. It is listed under Shopping & Fashion and its reputation is good. 83% of reviews are 4 stars or higher and 14% are 1 star; The business has replied to 64% of negative reviews; Reviews mostly discuss Product, Quality, Customer service. Last updated 2026-09-05.
What reviewers say
AI generated
Reviewers overwhelmingly had a great experience with this company. Customers frequently praise the exceptional comfort and soft texture of the undershirts, noting they feel wonderful and fit perfectly when worn. Consumers also appreciate the high quality and durable material that holds up well over repeated washes without losing shape or performance.
However, some people mentioned that certain items did not fit properly and required exchanges to get the right size. A few reviewers also noted occasional sizing challenges, pointing out that specific pieces felt too tight initially. Others experienced minor drawbacks regarding the fabric feel or material characteristics during warmer weather.
Auto-generated from all reviews of this business. For reference only.
My order was delivered to an address when in the US when it was supposed to go to Canada. I have been trying to get a response from someone at Underfit but so far nothing not even an acknowledgment of receiving my messages.
Reply from UnderFit2025-11-16
Hi Patrick, I should have responded faster, and that’s on me.
UPS had a tracking glitch that marked some packages “delivered” when they hit a transit facility in Torrance, CA, even though they were still in transit. Your order is either already delivered or still on the way. If it’s still en route, I can share the final-mile tracking link with the latest updates.
I’m here now and won’t leave you hanging.
These undershirts are above and beyond the best I've worn. They don't shrink or lose shape, they help wick away sweat more easily than cotton, and they always stay tucked in. The only thing you'd need to get used to is the slight see through material, which can be more noticeable with excessive chest hair. But it's an undershirt, so definitely not something to plan for!
Beige V neck undershirt did not fit. Attempted to contact through customer service and did not reach a resolution. Buy at your own risk.
Update: received a replacement that now fits. Happy with the quality of the product.
Excellent quality. These were the first undershirts I have purchased in years, and they fit wonderfully. I like the way that they regulate temperature and moisture even on the hottest summer days. After over a year of wear, they're still reliable. I would highly recommend.
Obsessed with these shirts. Great fit, sweat resistant, comfortable and best of all, I can wear a white button up with two buttons opened and you won’t see it!
UnderFit T-shirts are the best undershirts I've ever owned and will ever own. They're thin, they stay tucked in, they hold up great around the neck, and they last forever. I can't imagine wearing any other brand after going to UnderFit. Been wearing them for approximately 5 years.
I’ve been wearing Underfit shirts for years, and nothing else compares. The quality and comfort are unbeatable, and every time I wear one I feel confident and sharp. They’re an absolute essential in my wardrobe—I won’t go without them.
Do you value comfort, performance and longevity? UnderFit offers a premium product at a premium price point. Supporting a small business that funnels resources to ensuring consistent product quality is a net plus, too.
Great shirts. Perfect fit. Tried a couple of other brands once when Underfit was sold out of my size. Never again. UnderFit is the only choice for me now.
I have purchased various forms of performance Undershirts over the past 13 years or so. (I can't begin to imagine how much I've spent on ones that I didn't like). I never found a "perfect" one until Underfit. It's the first one where the sleeves don't stick out when I'm wearing it under a short sleeve t-shirt, it is long enough to stay tucked in, absorbs sweat well in the Arizona heat and most importantly they last. I have all the original ones I purchased over a year ago and have worn every week. They are in great shape still. Do yourself a favor, spend the money on these, it's a worthwhile investment in your comfort.
I was so happy to know that this brand was renewed. I was a big fan of the previous company Ribbed Tee's product and stoked to find out that UnderFit resurrected it. I have bought several of these and will be buying more to ensure I've got enough to last a lifetime.
Simply the best!
While the shirts do last a long time, I like to replace them annually to get that new shirt feeling.
I've tried other shirts, but I came back and will not leave again!
This t-shirt does its job by not showing, fits snugly, keeps me cool, and protects my dress shirts. In comparison cotton t-shirts are like another layer of clothing and create bunch up bulges.
I love the spec on the garment as you don't see it when you wear a shirt with first button unbuttoned. but the fabric is not good lot of my older shirts have the tencel or the modal burning out from the lyocell. looks like a burn out. this could be because your blending these fibers. over time the fabric is losing strength.
i wish you can make this in cotton spandex 160GSM product will be great and last forever and not stick to your body. you can take it one step further with Supima cotton. just my thoughts i am in the apparel business.
I’ve been wearing these for years. They fit great. Comfortable. They don’t come untucked. They protect your shirts. They last a long time. Customer service is excellent too. I was short a few shirts on my last order and the owner of the company fixed it himself in less than a day.
They’re a bit expensive, but totally worth it.
Just placed my 3rd order and will place 4th soon. I’ve been an avid undershirt wearer for 25+ years and these are the best ever. Slimming but not restricting, form fitting but not tight. Just perfect.
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