Tired of pit and sweat stains ruining all your good shirts? Here’s a helpful guide on how to keep sweat from staining and damaging your shirts. 

We explain where sweat stains come from, how to prevent them and how to get rid of those that have already formed. 

Why Do Sweat Stains Form?

Sweat is colorless, so why do yellow pit stains form on shirts? 

Pit stains form when substances in your sweat — salts, lipids and proteins — react with aluminum in antiperspirants. The reaction produces yellow substances that stain the shirt. 

Note: In some cases, sweat stains can also occur in the absence of antiperspirant. A mixture of sweat, body oils and dirt can leave behind stains. 

Several factors can make sweat stains more likely or make them worse. 

• Using too much antiperspirant. This causes some of it to transfer onto your shirt where it can cause yellow stains once you sweat. 
• Having hairy armpits. Some of the antiperspirant sticks on the hair, making it easier for pit stains to form.
• If you are a heavy sweater, then you are more likely to have pit stains on your shirts. You may also notice that pit stains only show up in the summer, when you sweat more from the heat. 
• Lifestyle factors like diet and excessive alcohol consumption can also increase the likelihood of pit stains by making you sweat more. 

5 Tips to Prevent Sweat Stains on Your Shirts

1. Wear an Undershirt 

Good undershirts are designed to wick or absorb sweat from the skin and keep it from reaching the outer shirt. 

An undershirt works as a barrier, keeping both sweat and antiperspirant from getting onto your shirt. Some undershirts such as those from Thompson Tee even incorporate sweat-proof armpits to provide stronger protection against sweat. 

Here’s a guide we wrote on how to shop for a good undershirt. One of the recommendations is to avoid cotton undershirts if you sweat heavily or for intense activities that cause a lot of sweating. Cotton gets saturated easily and can cause sweat patches and stains on your shirt. 

Our very own Apollo undershirt is highly breathable, wicks away sweat and it’s odor-resistant to keep you smelling fresh. 

2. Use Antiperspirant Properly 

Getting yellow pit stains on your shirt doesn’t necessarily mean that you have to stop using antiperspirant or switch to one of those natural options that don't really work. 

Just changing how you use antiperspirant can prevent pit stains from forming. Here are some tips on how to use antiperspirant properly to prevent sweat stains. 

• Don’t over apply antiperspirant. A light application is enough for antiperspirant to work well. 
• If you use gel or spray antiperspirant, let it fully dry before you put on clothes. This prevents the antiperspirant from transferring onto the shirt. Do this even if you are wearing an undershirt. You don't want your white undershirts getting unsightly pit stains. 
• Some people find that switching to a dry or solid antiperspirant gets rid of sweat stains. It doesn't transfer onto clothes as easily as gel antiperspirant.    

3. Switch to Aluminium-free Antiperspirant 

If switching to solid antiperspirant doesn't stop the stains, consider going aluminum-free. 

Just keep in mind that aluminum-free antiperspirants are actually deodorants. They can keep you from smelling sweaty, which is what deodorants do, but they won’t keep you from sweating.  

You may still get sweat patches on your shirt, but the yellow pit stains will be gone. 

4. Don’t Leave Shirts Unwashed for Too Long

Sometimes, pit stains will form after you’ve taken off your shirt. While it’s in the hamper, sweat compounds continue to react with aluminum, resulting in stubborn pit stains. 

Getting into a habit of laundering your shirts as soon as possible after you take them off will reduce the risk of pit stains. And even if some stains appear, they usually come off easily in the wash. 

5. Reduce Your Sweating 

Reducing how much you sweat can prevent pit stains. One simple way to do this is wearing more breathable clothing. This keeps you cool and reduces sweating. 

Also watch your diet. Foods like caffeine, spicy foods and junk foods can make you sweat more or make your sweat more likely to form stains (by changing sweat composition). Cutting down on your alcohol intake will also reduce how much you sweat.

How to Get Rid of Pit Stains

If your shirts are already marred with pit stains, don't worry, they are not permanent. But depending on how deeply set they are, you may need to apply several rounds of treatment to get rid of them. 

Here are a few things to try. 

• For fresh stains that have not completely set in, a regular laundry cycle can get rid of them. Rub some white vinegar on the stains before throwing the shirts in the wash.
• For more stubborn stains, soak the shirts in water containing oxygen bleach such as Oxiclean for an hour or overnight for extra-tough stains. Do not use chlorine bleach; it can worsen pit stains. 
• Aspirin also works. Crush two tablets in a cup of hot water. Rub the mixture on the stains and leave it overnight before washing the shirts.