Underarms and why clothing discolours there
Short answer: Yellow or grey patches under the arms are usually caused by a mixture of sweat, deodorant residue and a wash that does not remove everything. It is an ordinary mechanism and not a sign of poor clothing.
What happens in the underarm
The underarm is a warm, enclosed place where the body produces sweat and where clothing sits close and stays all day. Sweat itself is almost odourless and colourless, but it mixes with the skin's natural oils and with residue from deodorant or antiperspirant. The mixture works into the fabric and can over time cause a discolouration that is hard to remove. It is thus an interplay of factors and not just a question of how much you sweat.
Deodorant and fabric
Some deodorants and antiperspirants contain substances that bind to the fibres and leave a hard, yellowish coating. Give the product a few minutes to dry before you get dressed. Do not use too much, and try a different type if you have trouble with stains. See bamboo T-shirts for men. A light T-shirt shows discolouration faster than a dark one, so it can be an idea to have several colours.
Washing that gets everything
Wash the garment after each wear, so sweat and residue do not dry in. Turn it inside out so the underarm has maximum contact with the water. Pretreat stains with a mild stain remover or a soft brush and a little detergent before you put the garment in the machine. See bamboo long sleeve T-shirt for men. Avoid too high a temperature, which can fix proteins in the fabric. Wash at 30 to 40 degrees with an ordinary detergent that suits the fabric.
Stains that are already set
If you already have stains, you can soak the garment in lukewarm water with a gentle product. Rub carefully with a soft brush and rinse thoroughly. Do not use strong products, which can damage the fibres or change the colour of the fabric. Try first on a hidden spot. Some stains never disappear completely, and then you can use the garment as an innermost layer, where the discolouration is not seen. Viscose from bamboo is more vulnerable when wet, so go easy on it while it soaks.
Fit and air circulation
A loose cut at the underarm lets in more air, and air helps sweat evaporate. Tight clothing keeps moisture close to the skin and leads to discolouration faster. Check that the sleeve does not press and that the fabric can breathe. See bamboo sweatpants for men for relaxed clothing at home, when you want to give the top a rest. When you rotate between several pieces, each one has time to dry completely.
Care that extends the life
Hang clothes up to dry and avoid the tumble dryer at high heat, which can set stains. Avoid fabric softener, which can leave a coating on the fabric and make it less breathable. Change clothes when you have sweated a lot, and let them air before you put them in the laundry. If you sweat unusually much, or if the smell of the sweat changes, talk to your doctor, as it may have other causes.
Frequently asked questions
Why do T-shirts turn yellow under the arms
Because sweat, skin oils and deodorant residue form a coating in the fabric, which discolours over time.
Can I remove yellow stains that are already there
Often partly. Soak, rub gently and wash again. Try a hidden spot first and do not use strong products.
Does choosing looser clothing help
Yes. A loose cut lets in more air, so sweat evaporates more easily and settles less in the fabric.
You can find the full range at Bamboo-Clothing.com.
