Clothes that chafe under the arms

Short answer: Chafing under the arms comes from a seam that sits wrong, a fit that is too tight, or moisture. The three can be solved one by one, and changing just one of them is often enough.

The armhole seam

The seam between sleeve and body sits right in the armpit, where the skin is thin. If it is thick or raised, it rubs with every movement, and after a full day the skin can be red and sore. A flat seam lies against the fabric and is felt far less. See the styles in bamboo t-shirts for men.

A fit that is too tight

If the sleeve or armhole is too narrow, the seam is pressed into the skin every time you lift your arm. A size up or a different cut often solves it. The same principle applies elsewhere on the body where clothing is tight and seams rub, for example in the crotch of bamboo sweatpants for women.

Moisture softens the skin

Damp skin chafes more easily because it is softer and reacts more strongly to rubbing. The armpit is one of the places where you sweat the most. A fabric that moves moisture away from the skin reduces the problem noticeably. See men's bamboo undershirts, worn closest to the skin under a shirt or jumper.

An undershirt as a layer in between

An undershirt absorbs sweat and puts a smooth layer between the skin and outer clothing. Then it is the soft seam of the undershirt that sits in the armpit, not the stiff seam of the shirt. Choose an undershirt that fits close without squeezing, so it does not fold under the arm.

Summer and warmth

Chafing under the arms happens most in summer, because moisture and warmth make the skin softer and the rubbing stronger. You also move more and often wear thinner clothing, where the seam sits directly on the skin. Change into a dry top during the day if you have sweated a lot.

Washing and residue

Detergent and softener residue also sits in the seams and can make chafed skin more irritated. Wash with a neutral detergent and skip the fabric softener. Wash tops and undershirts after each wear when you have sweated in them. Let them air dry and follow the care label.

How to try clothing on

When you try on a top, lift your arms, stretch them forward and twist your upper body. Notice whether the armpit seam presses or the sleeve pulls up. If you only stand still in front of the mirror, you will not notice. A seam chafes in movement, and that is where you should test it.

When the skin is already chafed

If the skin is already chafed, keep the area dry and avoid rubbing until it has healed. Wear a soft undershirt or a top with flat seams meanwhile. If the skin does not heal, you get sores or a rash, or it keeps coming back, talk to your doctor.

Frequently asked questions

Does an undershirt help

Yes, often. It absorbs sweat and puts a smooth layer between skin and outer clothing, so its soft seam is what sits in the armpit.

Why does it happen mostly in summer

Because moisture and warmth make the skin softer and the rubbing stronger. You also move more and wear thinner clothing directly on the skin.

Can anything be done about the seam

A tailor can flatten it, but it is rarely worth the trouble on a t-shirt. It is easier to choose a style with flat seams.