Is Sweat or Deodorant Responsible For My Pit Stains?

Technically, it's neither.


That yellow, crusty residue taking up permanent residence inside your favorite shirts is due to an unfortunate reaction between sweat and antiperspirant, and you may be surprised to learn that deodorant is just an innocent bystander.

Deodorants are designed to do only what their name implies — deodorize by eliminating, absorbing or masking the smells that accumulate in your armpits. Antiperspirants also are self-explanatory; they minimize the amount of sweat that seeps out of your skin and onto your shirt.

But antiperspirants aren’t perfect. They still allow some sweat to escape, and they turn that sweat yellow. “The yellowing is due to perspiration chemically reacting with either the aluminum or the zirconium — or both — in the antiperspirant,” says cosmetic chemist Mort Westman.

If you’re committed to wearing antiperspirant, rather than deodorant, there’s no great way to prevent the stains. There is, however, hope for your already stained shirt, at least per the Stain Solutions group at the University of Illinois:

  1. Scrape off your crusty sweat from the shirt.
  2. Soak the shirt in water, dish soap and ammonia.
  3. Rub the stain and soak again.
  4. Rinse and soak in an “enzyme product” — we’re talking stain removers here.
  5. Finally, wash the shirt normally.

If this regimen sounds like it will induce a gnarly headache, save yourself some time and just buy cheap undershirts. Life hack!