If you've ever removed your favorite white T-shirt only to find the fabric near your underarms marred by sweat stains, then we've got news for you: It's not perspiration alone that's to blame. In fact, your antiperspirant -- designed to prevent sweat -- is often the cause of these unsightly stains.
Before you toss your antiperspirant in the trash, however, check the label. If it reads "deodorant" only (and isn't combined with antiperspirant), you're probably in the clear. Deodorants prevent odor-causing bacteria, while antiperspirants prevent sweat. To do so, antiperspirants rely on aluminum-based compounds, such as aluminum chloride, to cause cells in your sweat ducts to swell and block sweat from escaping. When these active ingredients (which also happen to be quite acidic) bond with your sweat, they're prone to stain clothing. Aluminum compounds also have been linked to Alzheimer's disease and breast cancer. Fortunately, scientific reviews refute the dangers of absorbing aluminum through antiperspirants, so your biggest concern rests on stain removal [source: Kramer].
But, if you think waiting for your antiperspirant to dry will help prevent fabric stains, you're out of luck. Some of the liquid-based product will still get on your shirt -- even if you apply only a very thin layer. That's why it's a good idea to steer clear of the roll-on or gel forms of antiperspirants; they're more likely to spread onto clothing than the solid cake form [source: IHHS]. Of course, we're still not suggesting you slather on your antiperspirant and top it with your best formal wear. To minimize staining, apply a single layer of antiperspirant and wait for it to dry before dressing. It may help to apply antiperspirant before bed. It will have plenty of time to dry before morning, and may even be more effective [source: IHHS].
When you encounter an antiperspirant stain, rinse the fabric with cold water -- preferably right after removing your clothing [source: University of Illinois Extension]. And don't pre-treat the area with a stain remover. This move could, ironically, make the stain permanent. That's because the acidity of antiperspirants is what causes them to discolor fabrics -- whether white or color-rich. Chemical-laden stain removers, as well as hot or warm water, can launch a chemical reaction that binds the stain to your clothing [source: IHHS].
Delicate fabrics with a fresh stain may benefit from a pre-soak in an ammonia/water solution. That's because ammonia is alkaline and will help neutralize the acidic antiperspirant. A set-in stain needs a pre-soak in a baking soda, water and white vinegar solution [source: IHHS]. If you're dealing with a fabric that's only recommended for dry cleaning, don't substitute a hand-washing. Your neighborhood dry cleaner has a better shot at removing the stain.
If your clothes-staining worries linger, opt for clear antiperspirants. The switch won't prevent stains long-term (the active ingredients are still a concern), but it will keep your clothes from exhibiting those pesky white marks that tend to appear if you don't have five minutes for your underarms to dry before dressing.