What Causes Pit Stains & How to Keep Them Off Dress Shirts

dress shirt pit stains

Discoloration and odors from sweat stains can age your favorite shirts prematurely. If you want to keep your threads looking (and smelling) fresh for as long as possible you need to learn how to prevent pit stains.

Causes of Armpit Stains

The first step in preventing stains is identifying pit stain causes. Once you know why they occur, you can take steps to prevent or reduce the problem.

Sweat Composition

Sweat comes from two types of glands, eccrine and apocrine. The eccrine glands are what get you sweating during physical activity. These glands cover a smaller area, such as the palms or armpits. Eccrine gland sweat is mostly water.

The apocrine glands cause perspiration while experiencing stress, fear, or anxiety. This sweat composition is fattier, including more proteins and nutrients. As a result, the sweat is thicker, has a stronger odor, and more likely to cause a stain.

Either type of sweat composition can cause a stain, although apocrine stains set in more easily. 

Antiperspirant Chemicals

The chemicals in some antiperspirants can interact with your sweat, causing a reaction that can stain shirts. You can try switching up your brands, trying a natural deodorant, or doing an armpit detox to see if this resolves your pit stains.

Sweat Volume

The more you sweat, the greater the risk of staining your clothes. Moisture-wicking fabrics can actively remove sweat, reducing the risk of a stain. Other fabrics, even natural ones, cannot wick away significant volumes of sweat fast enough. 

To prevent pit stains from a large volume of sweat you need fast-acting sweat-wicking clothing and/or to find a way to reduce sweat. If a significant amount of perspiration builds up on your shirt, it is best to wash it soon to prevent the stain from setting in.

Washing Techniques

Improper washing techniques are a common cause of premature staining. Failing to fully remove sweat and bacteria allows discoloration and odors to remain. The more improper wash cycles a shirt goes through, the worse this problem becomes.


As much as we all love a little fun in the sun, that same sunshine can do real damage to our clothes. Fading can happen easily with too much exposure to UV rays and the sun can cause discoloration on clothing that uses bleach. This is especially true for white shirts. 

If you use bleach on your shirts, it’s best to avoid hanging them out in the sun to dry.

Pit Stain Prevention

Sweatproof Undershirt

A good sweatproof undershirt is the simplest and one of the most effective ways to prevent pit stains on any clothes. Worn under your favourite shirts, you can protect them from staining while actively wicking away sweat. As a result, you have dryer pits, greater comfort, and less body odor.

Shop advanced sweatproof undershirts, tees, and polos from Neat Apparel. Our moisture-wicking fabric has proven comfort and efficacy.

Deodorant Habits

Deodorant use is pretty simple. As a result, most of us were never really taught how to properly use and choose it. Try to change up your habits and see how they affect your sweat, and how your sweat interacts with the deodorizing chemicals.

A few ways to vary things up include wearing less, trying a different type, or even trying natural. As well, if you find your deodorant or antiperspirant starts wearing off fast, consider multiple applications throughout the day. Everyone’s body is different and “24-hour protection” for one person may only be a few hours for another.

Trim Your Armpit Hair

Armpit hair can be helpful. It prevents chafing and provides protection from bacteria. But when there’s too much, it can be more of a hindrance than a help. Armpit hair traps moisture which can lead to sweat pooling, causing stains and odors. Too much hair can also prevent proper antiperspirant application, making it less effective.

When trimming your armpit hair it’s best to avoid stubble. Stubble can irritate the skin. Instead, leave the hair at a controlled length or shave it off completely.

Act Fast

If you don’t use sweat-wicking shirts, stains can set in quickly. The sooner you can wash out a stain, the better the chance you have to prevent pit stains from setting. Even applying water can help if laundry is not an option. At the very least, it’s good to get out of the shirt instead of continuing to sweat into it.

If pit stains are a common problem, consider carrying a backup shirt with you to change into while your shirt dries. Of course, a sweatproof undershirt can help avoid this issue altogether.