Why is it that some people's sweat stains turn their shirts yellow, but other don't?

Answer 1

This usually happens under the arms within the armpit. I believe it is more to do with the reaction of perspiration with under arm deodorant that tends to stain clothing, especially light colours. Try changing your brand of deodorant when you start wearing brand new clothes to see if there is a difference long term, I can recommend the brand called 'Mitchum' if you can find it dependant on what Country you live. No point in expecting it to lessen the yellow on existing clothes though as they will stay yellow but may lessen with washes.

Answer 2

a