9 Main Differences Between a T-shirt and an Undershirt


At first glance, the undershirt and the T-shirt look very similar, but their role is entirely different today. It used to be that the T-shirt and undershirts were the same, but today there are quite a few differences between them. So what is the difference between a T-shirt and an undershirt?

A T-shirt is outerwear, and an undershirt is an underwear. Any T-shirt cannot be an undershirt. Because an undershirt is made of sweat-absorbent materials, it is tight-fitting, long enough to be tucked into trousers, and has a deeper neckline so that it is not visible up the shirt. 

The following are the 9 main differences between an undershirt and a T-shirt. In the end, one more suggestion is when you can wear an undershirt so it can be seen.

What is the difference between a t-shirt and an undershirt?

The definition of a T-shirt is that it is a short-sleeved shirt that is shaped like the letter T, which is how it got its name. Some undershirts have short sleeves and are similar in shape to a T-shirt. But when you put both on, the difference is noticeable:

  1. The undershirt is more elastic and more fitted than the T-shirt,
  2. the purpose of the undershirt is to absorb sweat,
  3. the T-shirt is thicker and the undershirt is thinner,
  4. the undershirt is more breathable than a T-shirt,
  5. the undershirt is longer and reaches to the middle of the buttocks,
  6. the undershirt has shorter sleeves so that they are not visible under clothing,
  7. the undershirt will make you look slimmer,
  8. the undershirt will make you feel less hot in summer,
  9. the materials of the undershirts do not trap odors.

Now let’s see what these differences mean and what you need to consider when buying your next undershirt.

The undershirt is more elastic and more fitted than the T-shirt

The undershirt is more fitted to the body than the T-shirt because it is made of more synthetic fibers, which are more elastic. T-shirts are usually made of 100% cotton or a cotton-dominated fabric blend. Cotton is not so elastic a material that it can fit against the body; therefore, a T-shirt is unsuitable for wearing as an undershirt.

The undershirt should be tight so that it does not wrinkle when worn, as this may show through the clothing, which is not good. I suggest you read this post, where I explain why it is not good to have the undershirt showing through the clothes and how to prevent this.

If you buy your undershirt online, it isn’t easy to know which size is right for you just by looking at the picture. Most sellers have a size chart next to them to help you. But I’ve put together a detailed guide on how to take your body measurements to make sure you don’t buy an undershirt that’s too tight or not loose for you.

The purpose of the undershirt is to absorb sweat

The primary purpose of an undershirt is to protect the outer clothing from sweat. We sweat a lot during the day, and sweat soaks into our clothes and gradually ruins them. That is why we wear underwear to protect our clothes and absorb sweat.

Our outer clothes develop embarrassing sweat stains that ruin our appearance when we sweat. An antiperspirant can turn yellow on contact with sweat, which is noticeable on your clothes and difficult to remove. Good quality undershirts are specially lined in the underarm areas to absorb more sweat and not transfer it to outer clothing.

Yellow stains on white T-shirt
Yellow stains on a white T-shirt

the T-shirt is thicker and the undershirt is thinner

A T-shirt is an outer clothing garment and is therefore made of thicker fibers to protect us. The undershirt should be as thin as possible, unnoticeable, and absorbent, as its purpose is to protect the outer clothing from sweat.

Many undershirts are also made of cotton but use finer cotton fiber. T-shirts, on the other hand, use thicker and softer cotton fibers. Therefore, a plain T-shirt is not suitable to wear as underwear because it is too thick and would be too visible through thinner clothing such as a dress shirt.

the undershirt is more breathable than the T-shirt

Cotton itself is a unique material that breathes. Synthetic materials that breathe well are often added to the cotton blend (polyester, nylon, elastane). An undershirt that breathes well will ensure we start to sweat later.

Undershirts may have more elastic materials, as undershirts need to be tight, unlike T-shirts, which should not be too tight. T-shirts have more thick fibers to protect us and should be comfortable for longer.

The undershirt is longer and reaches to the middle of the buttocks

Another reason the T-shirt is unsuitable for wearing as underwear is that it is simply not long enough and would untuck out of the trousers when worn. T-shirts reach the middle of the buttocks, so they remain tucked into the trousers throughout the entire period.

If you are ordering your undershirt online, I advise you to take measurements to ensure that it is long enough for you. Most sellers include a size chart with the product, which gives the measurements for a particular size. You can find out how to take measurements for the length of your undershirt by clicking on this link.

the undershirt has shorter sleeves so that they are not visible under clothing

The primary purpose of an undershirt is to protect outer clothing; therefore, it should not be visible to wear. Undershirts have a tighter fitting and shorter sleeves, so they are not visible even if you are wearing a T-shirt with short sleeves.

This is also why the T-shirt is not suitable for wearing as underwear because most T-shirts do not have fitted sleeves and would therefore be visible when worn under clothing.

The undershirt will make you look slimmer

Undershirts are more elastic and tight-fitting, so they have a compressive effect on the body and squeeze the parts of the body where you have more fat. An undershirt will make you look slimmer and more elegant in your clothes, making you feel more confident.

In addition to regular undershirts, there are also compression undershirts, which have extra elasticity in the chest area and around the belly. These two areas (chest and belly) are the most visible through clothing for men. A compression undershirt compresses and lifts the body in these areas to make you look better.

If you are interested in learning more about compression undershirts, I suggest you read the more detailed post I wrote. In it, you will also find some suggestions on which compression undershirts to buy.

the undershirt will make you feel less hot in summer

Despite popular belief, wearing an undershirt in summer will not make you hotter, but it will even keep you cooler. However, in hot weather, an undershirt will keep you cooler and make you sweat less. Because undershirts are made from materials that breathe well, wick, absorb sweat, and dry quickly.

When we sweat in hot weather, the sweat stays on our skin, which makes us sweat even more. If you wear underwear that absorbs a lot of sweat, you will sweat less. And because underwear breathes well, you’ll also start sweating later.

I suggest you read some suggestions on how to wear and choose the right undershirt in summer.

The materials of the undershirts do not trap odors

Even a little sweat on your clothes can cause an unpleasant smell. That’s why some undershirts are made of unique materials that don’t trap odors and don’t smell even if you sweat a lot. Such an undershirt will protect your clothes from underarm sweat stains and prevent odors.

Can any shirt be an undershirt?

Not every shirt can be an undershirt. The undershirt must fit tightly, breathe well and absorb sweat. The undershirt shall be longer and reach the middle of the buttocks so that it does not slip out of the trousers. Good quality undershirts shall be made so that they do not trap odors.

Above I have already given 9 differences between an undershirt and a T-shirt, which confirm that not every shirt is suitable to be worn as an undershirt. You should consider at least these 3 characteristics before buying an undershirt:

  1. That it is made of sweat-absorbent materials (cotton, nylon, wool),
  2. It must be long and tight enough, and
  3. It is not noticeable under the clothes you are wearing.

The colors of the undershirts are the main contributors to visibility through clothing. The most common color of undershirts is white, which is the least suitable choice. To find out which color undershirt to choose, read this post.

Can you wear an undershirt as a shirt?

The undershirt is not very suitable to be worn as a shirt. It is suitable for wearing during sports, at home, or under an unbuttoned shirt. However, it is unsuitable for wearing as a shirt because it is too tight and its length makes it necessary to keep it tucked into the trousers.

Undershirt under an unbuttoned shirt
Undershirt under an unbuttoned shirt

As part of an outfit, the undershirt can be seen on athletes, singers, and rappers who have this style and even wear the undershirt on red carpets. This is a more extravagant style of dress, which is not exactly in line with fashion rules. However, you don’t have to look at the rules if you like them.

Gregor

My name is Gregor and I'm a sports and fashion enthusiast. Like you, I want my clothes to be good quality and comfortable. I hope my articles will help you choose the right underwear for you.

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