Sweat marks that stay after washing

Short answer: Sweat marks are salt and protein mixed with skin oil. Soak the garment in lukewarm water with an enzyme detergent before washing as usual.

Why an ordinary wash is not enough

A short cold wash does not lift the oil, and the salt crystallises in the fibre. The result is a stiff, pale area that grows more visible with every wash. It shows most on the back of t-shirts and in shirt collars.

Soaking does the work

Fill a bowl with lukewarm water and a dose of enzyme detergent. Put the garment in and leave it for two hours or overnight. The enzymes break down protein and oil so the following wash can rinse them away.

For stiff, old marks

Mix a paste of bicarbonate of soda and water, spread it on the area and leave it an hour. Rinse and then wash at the highest temperature the fabric allows. Repeat rather than reaching for bleach, which yellows the mark. See bamboo t-shirts for men.

How to get fewer of them

Wear a thin undershirt under your shirt, change more often in warm spells, and let clothes dry fully before they go in the basket. See bamboo undershirts for men and bamboo undershirts for women.

Frequently asked questions

Why do sweat marks turn yellow

Rarely because of the sweat itself. It is aluminium from antiperspirant reacting with protein.

Does washing hotter help

Only if the oil has been loosened first. Otherwise heat bakes the mark in.

Can underarm marks be removed completely

Fresh ones yes. Old stiff marks usually get lighter but rarely disappear.