How to Get Sweat Stains Out of a White Shirt (and Keep Them Out)

To get yellow sweat stains out of a white shirt, make a paste of baking soda and a little water (or hydrogen peroxide, plus a drop of dish soap), work it into the underarm, let it sit for 30–60 minutes, then wash as usual in cool or warm water. Repeat before the shirt ever goes in the dryer, and don't use chlorine bleach, which can make the yellow worse. Most underarm yellowing comes from antiperspirant residue reacting with sweat and body oils, not from sweat alone, so the long-term fix is changing how you apply deodorant and how you wash.

Here's what causes the stains, a step-by-step method that works on most white shirts, what to avoid, and how to keep it from coming back.

What causes yellow sweat stains?

Sweat on its own is basically colorless. The yellow comes from a reaction: the aluminum compounds in most antiperspirants mix with sweat and body oils and build up in the fabric. Each wash removes some of it, but not all, so the stain darkens gradually over weeks and months. That's why a shirt can look fine for a while and then suddenly look dingy under the arms.

Two things speed it up: putting a shirt on before your deodorant is dry, and washing or drying in a way that sets the residue in place (more on that below).

How do I remove sweat stains from a white shirt? (step by step)

1. Check the care label and test first. Try any treatment on an inside seam if you're not sure how the fabric will react.
2. Rinse the underarms in cool water to loosen surface residue.
3. Apply a paste. Mix about three parts baking soda to one part water. For tougher yellowing on white fabric, use hydrogen peroxide instead of water and add a small squirt of dish soap, which helps break up the oils.
4. Work it in with an old toothbrush or soft brush, both inside and outside the underarm.
5. Let it sit for 30 minutes to an hour.
6. Wash as usual with a good detergent. An enzyme or oxygen-based detergent booster helps on older stains.
7. Check before drying. If the stain is still there, repeat the treatment. Hang the shirt to dry until you're sure the stain is gone, because heat can set what's left.

Very old, set-in stains may need two or three rounds, or an overnight soak in oxygen bleach (sodium percarbonate) dissolved in warm water. Some stains that have been baked in by years of hot dryer cycles won't fully come out.

Which method should I try first?

What should I not do?

• Don't use chlorine bleach on sweat stains. It can react with the residue and turn the yellow darker. Oxygen bleach is the better choice.
• Don't put a stained shirt in a hot dryer. Heat can set the stain. Air-dry until it's gone.
• Don't mix chemicals. Never combine chlorine bleach with vinegar or ammonia; the fumes are dangerous.
• Don't scrub hard enough to fuzz the fabric. Let the paste do the work.

Do performance (synthetic) dress shirts get sweat stains?

They can. Antiperspirant residue builds up on any fabric. The difference is that a polyester performance fabric wicks sweat away and dries quickly, so moisture doesn't sit in the fabric as long, and it tends to release residue in a normal wash more easily. Performance fabrics can hold on to odor, though, so wash them regularly in cold water and skip fabric softener, which can coat the fibers and trap smells. Our white performance dress shirts are machine washable in cold water, and the same baking soda method above works on them.

How do I prevent sweat stains in the first place?

• Let deodorant dry fully before you put a shirt on. This one change makes the biggest difference.
• Use less. A thin layer works as well as a thick one and leaves less residue.
• Try applying antiperspirant at night. Many dermatologists suggest it, because it has time to work while you sweat less.
• Consider an aluminum-free deodorant if yellowing is a constant problem. It won't stop sweat the same way, so it's a trade-off.
• Wash white shirts after every wear, and pre-treat the underarms every few washes before buildup becomes visible.
• Wear an undershirt if you sweat heavily. It's cheaper to replace than a dress shirt.
• Rotate shirts. Owning enough white shirts that each one isn't worn and washed constantly makes them all last longer. A shirt like the Range Shirt in White is designed for that kind of daily wear.

Frequently asked questions

Does vinegar remove sweat stains?

Vinegar helps loosen deodorant residue and removes odor, especially as a 30-minute soak before washing. For yellowing that's already visible, a baking soda or hydrogen peroxide paste usually works better.

Can hydrogen peroxide damage my shirt?

On white fabric it's generally safe in the small amounts used for spot treatment, but test it on a hidden area first. Don't use it on colored shirts, where it can lighten the dye.

Why do my white shirts turn yellow under the arms but nowhere else?

Because that's where antiperspirant meets sweat. The aluminum compounds in antiperspirant build up in the underarm fabric over many wears and washes.

Can I remove sweat stains from a shirt that's already been through the dryer?

Often, yes, but it takes more work. Try an overnight oxygen bleach soak, then the paste method, and repeat. Very old stains set by heat may only fade, not disappear.

How often should I wash a white dress shirt?

After every wear. Sweat and body oil build up even when the shirt looks clean, and that buildup is what turns into yellowing over time.

Related reading: How to Keep a White Dress Shirt White and Performance vs Non-Iron vs Cotton Dress Shirts.