The Science Behind Pit Stains & How to Stop Them

Are you bothered by pit stains? We’ve all been there. It’s embarrassing to flash yellow sweat stains when raising your hand during a meeting or waving to a friend.

And don’t even get us started on laundry day. Pit stains are an absolute pain to clean, or even impossible to get out altogether. It’s painful (and wasteful) to throw away an almost perfectly good shirt.

We’ve got good news, though. Pit stains don’t have to plague your day-to-day life! Read on to discover the science behind pit stains and the best ways to prevent and remove yellow underarm stains from clothing.

Together your antiperspirant, sweat and cotton undershirt are a deadly yellowing combination that make those tough to get out.

How Armpit Stains Form

What causes yellow armpit stains? Newsflash: It’s not just sweat.

Here’s the basic science: pit stains occur when the proteins in your sweat react with the aluminum and other chemicals in your antiperspirant.

Aluminum is the active ingredient in most over-the-counter and prescription antiperspirants, while your sweat consists of water, ammonia, urea, salts and sugar. Sweat, on its own, is actually odorless and colorless.

As the composition of your sweat mixes with the ingredients of your antiperspirant, the result is a pesky yellow pit stain that’s tough to get out. And if you regularly wear white undershirts, you’ll notice that the stain is much more apparent.

How to Avoid Pit Stains

So what’s the best way to stop and prevent yellow underarm stains?

Here are our top three tips for keeping pit stains at bay:

Make the switch from antiperspirant to deodorant Take proper care of your clothing Wear a sweat proof undershirt for protection

More tips on how to stop pit stain inducers.

1. MAKE THE SWITCH FROM ANTIPERSPIRANT TO DEODORANT

Looking to stop pit stains at the source? Cut back on applying aluminum-based antiperspirant to your underarms, and use deodorant instead.

Note that deodorant and antiperspirant are two different products. Deodorant masks body odor, while antiperspirant blocks your sweat glands to prevent perspiration. If you deal with axillary hyperhidrosis or excessive sweating, this tactic might not work as well for you.

If you’re looking for an effective, reliable deodorant, here are a few of our favorites:

Although most deodorants are aluminum-free, keep in mind that overusing deodorant can still produce yellow stains. Overapplying can cause the product to rub off on your shirt and reduce its effectiveness.

Additionally, remember that deodorants (and antiperspirants) work differently for everyone. What works for one person may be ineffective for you. Don’t give up on finding the right product for your needs!

2. TAKE PROPER CARE OF YOUR CLOTHING

By following proper laundry protocol, you can reduce the occurrence of pit stains (or even avoid them altogether).

If you’re prone to pitting out, follow our suggestions for taking good care of your shirts and preventing pit stains:

Don’t wait too long to wash sweaty shirts - the stain will have time to set in permanently. (Plus, damp sweat is a breeding ground for bacteria.)

Make sure to pre-treat severe stains before tossing the shirt in the wash. Products like OxiClean can be effective, but only when used correctly. You can also try other DIY methods, like aspirin or a vinegar and baking soda combination.

Skip the bleach. Although bleach has whitening effects, it actually worsens pit stains on fabrics like spandex, wool, silk or leather. The same goes for drying your clothes out in the sun.

Dry on low heat or air-dry if possible - heat can make stains more difficult to remove if they’ve already set in.

Take your shirt to the dry cleaner if necessary, and let the cleaners know to pay special attention to any severe stains.

More on how to remove sweat stains from clothing.

3. WEAR A SWEAT PROOF UNDERSHIRT FOR PROTECTION

A sweat proof undershirt is the easiest, most economical way to stop pit stains from showing through your clothes.

Recurring pit stains and constant laundering can drastically reduce the lifespan of your shirt. Wearing a sweat proof undershirt protects your outer layers of clothing, meaning you won’t have to launder as often or use chemical-based products to remove stains aggressively. Plus, you’ll save hundreds (or even thousands) of dollars that you spend on replacing your shirts every few months.

For the best sweat proof undershirt, look no further than the Thompson Tee. The Thompson Tee is the only patented sweat proof undershirt on the market. Each sweat proof Thompson Tee contains Hydro-Shield technology that can withstand and block 100% of armpit sweat and odor from reaching your outer layers. Absolutely no more pit stains - guaranteed.

Ready to eliminate pit stains for good and regain your confidence? Try a Thompson Tee for 20% off with code TEES20.

Be sure to check out our resource pages for more information about sweat and sweat stains.