You wear an undershirt under a shirt if you want to protect the shirt from sweat and deodorant, if the fabric is thin or light and your skin shows through, or if you have a long working day ahead. Then choose a close-fitting undershirt with a V-neck in a skin tone or light grey, not white, so that it stays invisible. Under a polo or a shirt with an open collar you usually do not wear an undershirt, because it then becomes visible and the polo itself is already meant as the first layer. On warm days, you are better off choosing a breathable shirt without an extra layer.
Why men wear an undershirt
The undershirt has a practical history: it protects the shirt. Sweat, skin oil and deodorant end up in the undershirt instead of in your shirt. As a result, shirts last longer, get yellow edges in the collar and under the arms less quickly, and you need to wash them less often. In addition, an undershirt can prevent a thin white shirt from showing through and gives a smoother silhouette. In winter it also adds an extra layer of warmth.
Still, the undershirt is not an obligation. More and more men wear their shirt directly on the skin, especially in summer and with shirts in a sturdier fabric. It depends on the situation.
When yes and when no
| Situation | Undershirt? | Why |
|---|---|---|
| White shirt, thin fabric, office | Optional | Can limit show-through and absorb moisture |
| Long working day or important presentation | Optional | Can be pleasant if you perspire quickly |
| Shirt with open collar, two buttons undone | Only with a deep V-neck | Otherwise you can see the undershirt |
| Knitted polo | Personal choice | Pay particular attention to visibility at neck and sleeves |
| Hot summer day, little client contact | No | An extra layer makes it warmer |
Which undershirt to choose
- Neckline: a V-neck is almost always better than a crew neck. That way the undershirt stays invisible if you leave the top button of your shirt open. A deep V-neck also works with two open buttons.
- Colour: under white, a shade close to your skin is often less noticeable than bright white. Test this in daylight, as it differs per skin and fabric colour.
- Fit: close-fitting, without folds. A loose undershirt makes bumps under your shirt.
- Length: long enough to stay in your trousers when you bend or stretch.
- Material: a thin, breathable material such as fine cotton or a light stretch fabric. A thick fabric makes the whole thing warm.
Under a white shirt
A white shirt is the piece where an undershirt is most often worn, and with reason. The Hamilton shirt in white is made of 100% cotton and has an Italian collar that falls open nicely without a tie. If you wear it with the top button open, choose an undershirt with a V-neck in a skin tone or light grey. That way you protect the white cotton from yellow edges and keep the collar clean.
With coloured shirts, such as the Hamilton shirt in light blue, the skin shows through less. An undershirt is then mainly handy to prevent sweat marks, which are more quickly visible on light blue than on white.
Under a polo
A polo, and certainly a knitted polo, is designed to be worn directly on the skin. An undershirt underneath quickly becomes visible at the neck or the sleeves, and makes the whole warmer. The Theodore open polo in light blue, for example, has an open collar without buttons. Any undershirt would be immediately visible there. Lyocell, the material of the Theodore, feels soft and cool on the skin, so an extra layer is not needed either.
The same applies to the Montgomery polo in navy, which drapes softly thanks to the blend with modal, and the Atticus striped cotton polo in white. With the white Atticus you can consider wearing a skin-toned undershirt if the fabric shows through slightly in bright light, but usually it is not necessary.
Undershirt and sweat marks
One of the most important reasons to wear an undershirt is to prevent visible sweat marks. A good undershirt absorbs moisture before it reaches your shirt, so no dark stains appear under your arms or on your back. That is especially pleasant with light blue and grey shirts, where sweat becomes visible fastest. For heavy sweaters there are undershirts with an extra layer under the armpits. The most important thing, however, remains that the undershirt fits closely and is made of a breathable material. A loose or thick undershirt traps heat and then works against you.
Deodorant plays a part too. Deodorant with aluminium can, combined with sweat, cause yellow edges on white fabric. The undershirt catches that, so your shirt stays white for longer. Always let your deodorant dry for a moment before you get dressed, with or without an undershirt.
Visible undershirt: never
An undershirt that peeks above the collar, sticks out below the sleeves or can be seen through a shirt makes an outfit look sloppy. So always check in the mirror, also in bright daylight. A white T-shirt under an open shirt is something else. That is a deliberate style choice for casual moments, not an undershirt.
Care
You wash undershirts more often than shirts, preferably after every wear. Because the undershirt catches sweat and deodorant, you can sometimes wear your shirt a second time or it needs less intensive washing. That reduces wear on the collar and cuffs. You can read more about cotton and how to care for it on our page about cotton.
Discover our shirts for Men and polos for Men, or put together a complete work outfit with the Office for Men collection.
Shop the look
Hamilton: shirt with Italian collar, white
Hamilton: shirt with Italian collar, light blue
Theodore: open polo without buttons, light blue
Montgomery: softly draping modal polo, navy
Atticus: striped cotton polo, white
Frequently asked questions
What colour undershirt do you wear under a white shirt?
A shade close to your skin is often the least noticeable, but test the combination in daylight.
Do you wear an undershirt under a polo?
You may. Just check whether neck and sleeves become visible and whether the extra layer stays comfortable.
Isn't an undershirt too warm in summer?
A thin, breathable undershirt is not too bad, but on hot days with little client contact you are better off leaving it out and choosing an airy shirt.
