Look at natural deodorants in more detail and you’ll also find that many formulas are free from phthalates, parabens, or talc, while underscoring plant-derived ingredients that target various underarm concerns. For instance, tea tree oil, which is known for its antibacterial properties, per the Mayo Clinic, is often included, while other essential oils derived from bergamot or rosemary provide fragrance. Arrowroot powder and charcoal are also formulated in some natural deodorants to help absorb moisture, Hadley King, MD, clinical instructor of dermatology at the Weill Medical College of Cornell University, tells SELF. The latter boasts antibacterial benefits, she adds.
Other ingredients you might find include alpha hydroxy acids (AHAs), which are chemical exfoliators, like glycolic or lactic acids, that help dissolve dead skin cells.1 Another perk? “AHAs can lower the armpits’ pH levels, making the environment less hospitable to bacteria responsible for the odor,” Dr. King explains.
Natural deodorants are often made with common irritants that can cause an armpit rash.
Natural deodorants often contain baking soda, or sodium bicarbonate, to help neutralize body odor. Its alkaline nature, which is more basic than the skin’s natural pH, can easily prompt a skin reaction, Neelam Vashi, MD, associate professor of dermatology at Boston University School of Medicine and director of the Boston University Cosmetic and Laser Center at Boston Medical Center, tells SELF. Due to baking soda’s well-known reputation as a potential irritant, some natural deodorant brands now offer baking-soda-free products for sensitive skin.
Other things to watch for on the label? Dr. Alexiades says vitamin E is a common ingredient that can irritate the skin or set off an allergic reaction. Other irritants or allergens can largely be found under the essential oil umbrella, such as limonene which can be found in rosemary extract, as well as lemongrass, lavender, tea tree, sandalwood, and peppermint oils, which are less likely to cause a deodorant rash but can still be culprits.
Finally, coconut oil, which usually acts as a skin conditioner in natural deodorants, may also cause irritation or an allergic reaction thanks to certain ingredients commonly added to it, Mayra Maymone, MD, a researcher at the University of Colorado dermatology department, tells SELF. She adds that lichen extract is a lesser-known plant-derived ingredient that may offer antibacterial benefits, but can similarly lead to skin issues.
Ingredients in traditional deodorants can sometimes cause an underarm rash and irritation too.
It’s quite common for people to have unique sensitivities in the underarm area to ingredients you might not find as irritating elsewhere on the body, says Dr. Alexiades. “The armpit is a delicate area: The skin is thin, folding of the underarm occludes products placed there, meaning anything that you place there penetrates and stays in contact much more than other areas, and it gets damp with perspiration, causing even more opportunity for ingredients to react,” she explains.
Add in substances like aluminum chloride, which has also been linked to skin reactions, and fragrance, which is high on the list of potentially irritating ingredients, and you can see why a deodorant rash may be in the cards. What’s more, aluminum-based deodorant may still contain plant-derived ingredients commonly found in its natural counterparts, so you’ll still want to scan for things like charcoal, essential oils, and other plant extracts.
What types of skin reactions should you watch for?
If you get an armpit rash from deodorant, it’s most likely a case of contact dermatitis, Dr. Skelsey says, adding that any of the ingredients mentioned above—and countless others—can trigger this reaction. One of the telltale signs of contact dermatitis is that the reaction will tend to be exactly in the pattern of application of the deodorant, Dr. Alexiades explains.