What Causes Sweaty Underarms? An Expert Explains

The first step to addressing a problem is understanding what it is. Excessive armpit sweating is also called axillary hyperhidrosis, and it could be focal or “localized to the armpit only, caused by hyperactive nerves,” or it could be secondary, wherein “excessive sweating affects the whole body, including the armpits.”

Dr. Chesca explains, “Primary focal hyperhidrosis is caused by faulty nerve signals that ‘switch on’ sweat gland activity, even during periods of rest.” It is worth noting that this is largely genetic and could be passed on through generations in families. On the other hand, secondary hyperhidrosis may be “a manifestation of medical conditions or certain substances.” Examples of the former are thyroid gland overactivity, menopause, low blood sugar, neurologic conditions, or anxiety, and that of the latter are caffeine, spicy food, or certain medications.

As mentioned, sweating is a normal bodily response to regulate temperature. For people with hyperhidrosis, however, “the sweat glands receive excessive or inappropriate signals, so sweating continues even when the body no longer needs to cool down further.”

Constantly managing underarm sweat can be a hassle for some, especially given the time, resources, and effort it requires. However, choosing to ignore the problem may cause more to arise. As explained by Dr. Chesca, “Persistent moisture could lead to irritation, chafing, overgrowth of microorganisms, which could worsen odor or cause other skin problems.”

“Psychological and emotional impact” is also an often-overlooked effect. “People with hyperhidrosis could get extra conscious about wearing certain fabrics, cuts, or colors of clothing which reveal visible sweat marks. They may worry about certain social situations or constantly worry about how they sweat or look.” The medical expert adds, “The constant friction, irritation, and inflammation in this area could leave hyperpigmentation, especially in Filipino skin, as a response to injury,” which could add onto the psychological and emotional toll.

Taking care of the underarm area starts with the basics. As enumerated by Dr. Chesca, these include “cleansing with a gentle cleanser, keeping the underarms clean and dry, wearing breathable fabrics, and changing out of sweaty clothes as soon as possible.” Deodorants and antiperspirants are also typically part of underarm routines, and while they are often used interchangeably, they address different concerns.

“Deodorants mainly help with odor through antibacterial ingredients, masking fragrances, or odor-neutralizing agents. Deodorants themselves don’t directly cause sweat glands to produce more sweat. At the same time, they don’t directly lessen sweat gland activity.” A deodorant may not be working well for you if you experience persistent odor despite regular reapplication. “You may also notice that the product leaves a residue, triggering itching and irritation, or may stop working after a few hours,” says Dr. Chesca.

It’s worth noting that “sweat itself is largely odorless.” The medical expert expounds, “Odor develops when sweat interacts with bacteria on the skin. If odor remains a problem, it may be worth reassessing the product, application habits, and getting down to the cause of odor through a consultation with a board-certified dermatologist.”

A pro tip from the expert: “It’s best to use antiperspirants at bedtime because that’s when they’re most effective. Sweat production is much less when you’re resting, giving the aluminum salts in antiperspirants more time to work in the sweat ducts without being washed or diluted by moisture and perspiration. This then leads to more effective temporary reduction in sweating the next day. You can wash the area with a gentle cleanser the following morning.”

Antiperspirants are formulated specifically to address sweat. They work by “forming gel-like plugs near the top of sweat ducts, as their salts dissolve in sweat and moisture upon contact with the skin. With the ducts temporarily blocked, there is less flow of sweat towards the outside of the body.” The plugs dissolve after the skin sloughs off, making the effect temporary and warranting reapplication after 24 hours. Dr. Chesca suggests using an antiperspirant with aluminum salts as a first-line option if your main concern is sweating.

If sweating remains excessive after applying the aforementioned measures, it may be time to seek medical advice. “A dermatologist-guided treatment plan could include prescription topical medications, botulinum toxin injections, energy-based treatments like radiofrequency microneedling, or even surgical procedures for cases that do not respond to less invasive treatments.”

Any redness or irritation that occurs must be addressed early since “Filipino skin and darker skin types heal with hyperpigmentation.” Dr. Chesca adds, “It’s just as important to get to the root cause of irritation to avoid repeated exposures, especially since irritant substances are more likely to cause barrier damage when they interact with sweat.”

She also suggests seeing a dermatologist “if there is persistent excessive sweating, if the sweating happens even when you’re cool or at rest, if it repeatedly soaks through clothing, or if it interferes with your daily activities and confidence.” It’s also best to observe if you are consistently planning your outfits and activities around sweating, with the goal of avoiding visible sweat marks. According to the dermatologist, that may also be a sign that it’s time to consult a professional.

There are also medical conditions that can accompany excessive sweating, so it’s best to watch for physical symptoms like tremors and palpitations. It would be “very important” to seek medical evaluation if this is the case.

She concludes, “You don’t have to necessarily ‘live with’ excessive sweating on the armpits. It’s worth seeing a board-certified dermatologist for effective treatment options beyond simply switching deodorants or avoiding certain situations and clothing.”

Preview has curated a list of affordable antiperspirants, deodorants, and hybrids that contain aluminum salts that can help address underarm sweat. Shop ahead.

The Original Nourished and Smooth Stick by Dove has a moisturizing cream formula that not only softens and smoothens the skin, but also provides support and recovery for the delicate area, especially after shaving. With nourishing ingredients and antiperspirant properties, it provides underarms with 48-hour protection against uncomfortable wetness.

Want to feel fresher the more you move?  The Rexona Powder Dry + Brightening Spray boasts Motionsense Technology, a patented system of microcapsules that burst and release freshness with movement. That said, it offers strong protection against sweat and odor.

The Unscented Roll-On by Milcu is both a deodorant and antiperspirant, formulated to prevent odor and keep sweat under control. Being unscented, it works especially well for those with skin that’s sensitive to fragrances.

The Secret Platinum Protection comes in a soft, solid stick format that is fast-absorbing and leaves no residue on clothes. Apart from providing strong protection against moisture and odor, it is also infused with a fresh, clean scent.

If you want to stay feeling dry and smelling fresh, the Old Spice Captain can certainly help. As both an antiperspirant and a deodorant, it delivers long-lasting freshness and all-day sweat defense to keep you confident through any activity.