Why Do the Armpits of my Shirts Always Turn Blue or Black?

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Dear Home-Ec 101,
A couple of months ago, blue stains started appearing in the armpits of my light colored shirts, and on the darker shirts, there were even darker, but more normal looking, stains after the shirts were washed. At first, I thought the issue was the natural deodorant I had started using, but even after I switched back to normal deodorant, but the stains kept appearing. Then I thought the issue might be a certain new shirt I had bought which has dark blue floral patterns, so I began washing my laundry separately in lights and dark loads. But the stains are still appearing even when I wash only white clothing together. The stains only show up in the armpits, and they’re extremely difficult to get out.

Nobody else in my family is facing the same issue. I’m kinda freaked out that I’m gonna lose a lot of clothing to this so please help!
I’ve researched for hours and cannot find anything relating to my problem.

Smurfette in Smyrna

Thank you for writing in. You’ve explained a question we’ve gotten more times than you’d believe over the years. It relates closely to two posts that have been on the site for a very long time.

How to Deal with Stubborn Body Odor in Laundry and Pillowcases and Oily Skin (the questions were submitted as follow-up comments or emailed responses to the post).

Many people have emailed, asking why their shirts’ armpits turn black despite changing deodorants or switching to no deodorants. Also, people have written complaining about their spouse’s side of the bed changing colors. We’ve never had a good answer and never had anyone so thoroughly document their issue. Thank you for playing the laundry detective for us; those clues helped!

Sometimes black armpit stains are caused by your deodorant; if it’s black, it is usually aluminum. You can test this theory by switching to an aluminum-free deodorant and wearing a new shirt.

Yellow stains along the collar and underarms are sweat stains, and we’ve covered how to get rid of those in the past.

But blue? Blue stains that weren’t caused by dye transfer? That was interesting, and it’s why we finally connected to the underlying cause.

First, the disclaimer: we are not medical professionals, and this is not medical advice or a medical site. There is a pretty rare condition, but it does happen, and it does cause a person’s sweat to change colors.

Also, the condition is usually not super obvious. It’s not like a person suddenly looks like an old Gatorade commercial.

It’s a lot more subtle. For example, if you hang out on pregnancy boards, you’ll find people freaking out that their white toilet seats are slowly turning blue (and this is how I figured it out).

The condition is called chromihidrosis. You can learn more about it here. The quick and dirty explanation is that the sweat glands begin producing more pigment than normal for some reason. Sometimes it’s because of an underlying issue, and other times it’s not. So, please make an appointment and take a couple of shirts with you, because Lord knows sometimes it can be hard enough to get a medical professional to listen when it’s something common.

Chromihidrosis can cause human sweat to turn blue, black, yellow, green, or brown.

There is also a slightly more common condition called pseudochromihidrosis, which is the sweat reacting with something on the skin and then changing color, rather than the sweat itself being a color.

From reading, not going to school, and learning about the condition, remember, we are not giving medical advice. However, there are treatments for underlying causes and treatments to help with the sweating itself if your body has just decided to add some entertainment value to your already interesting enough 2020.

Unfortunately, we don’t have a solution for the stains left by the pigment itself. First, we would treat it like a sweat stain, go back up and click the link at the yellow stains around the collar, and if that doesn’t work, try treating the stains like a dye stain.

Mix Dawn dish soap (the kind without bleach) 1:1 with white vinegar directly to the stain and blot, then rinse with clear water. Follow that with rubbing alcohol, which you’ll remove first by blotting with either a clean rag or folded paper towels, followed by rinsing with clear water. If you still have a stain, your last resort would be 1:1 Dawn dish soap and ammonia, followed by a thorough rinse with clear water.

And a little bit of good news, we’re pretty stylistically challenged, so we had to look it up, but it appears there is a blue for every color type. Yay? Enjoy your new wardrobe?

Good luck!

Send your questions to helpme@home-ec101.com!

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1 thought on “Why Do the Armpits of my Shirts Always Turn Blue or Black?”

  1. I found this post while frantically trying to figure out how to save a sweater given to my by a recently deceased grandparent; for no apparent reason, it had grown the most bizarre blue stains in the armpit area.

    It’s an off white, 60/40 cotton/poly blend from JC Penny, and not at all high end, but hugely sentimental, and I desperately needed it to not be ruined. Vinegar helped rather a lot, but not enough for me to be able to wear it again. And, unfortunately, alcohol of any sort is still a bit thin on the ground in my neck of the woods.

    What *did* work was LA’s Totally Awesome. I genuinely only tried it because it seemed the least likely chemical to accidentally make mustard gas, or worse, if I wasn’t careful, and I’m so very happy I did. There’s a bit of a shadow where the worst stain was, but really only noticeable if you know what to look for, and the rest is just *gone*.

    Crisis averted, and thank you for setting me on the right path-although now I probably ought to go have a word or two with the doctor.


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