Armpit Sweat - How to Prevent it?
By Cynthia Bailey MD.
How common is hyperhidrosis (excessive sweating) and can you do anything to prevent it? As a dermatologist who has always been sweatier than most people I know, I make this topic something that I keep up. I personally don't like armpit marks on my clothing, I'm not fond of how deodorant and antiperspirants ruin fabric and I've tried everything available over the course of my career to control this hyperhidrotic superpower that I was born with. In this article, I'm going to share with you what I know about controlling armpit sweat.
How common is excessive armpit sweating?
In my experience, axillary hyperhidrosis is more common than we have thought in dermatology. Published medical studies estimating a low prevalence are, “outdated and underestimate,” according to a more recent medical study. (1)
- This same study estimates the incidence of axillary hyperhidrosis in the U.S. at approximately 5%.
- According to another study done in both China and Canada, the incidence was found to be slightly over 15%!
Other sources cite the incidence as much less.
Do men or women sweat more in the armpits?
Both genders are affected - the saying that "men perspire and women glow" is just a saying - we all sweat - and some of us sweat a lot!
Are some ethnicities more likely to have excessive armpit sweat than others?
There is significant ethnic variation in the incidence of hyperhidrosis. For example, it is 20 times more frequent in the Japanese than other ethnic groups. Sources cite armpit (axillary) hyperhidrosis as occurring in approximately 5% of the population. The term hyperhidrosis involves more than armpit sweating, though.
What is hyperhidrosis?
Hyperhidrosis is the medical name for excess sweating. It can involve either axillary skin (armpits), palms or facial skin, or it can be generalized.
The diagnosis of hyperhidrosis is made if a person has excessive sweating for over six months without an obvious cause AND the sweating has two or more of the following characteristics:
- It impairs daily activities.
- It occurs symmetrically on both sides of the body (like both armpits) at least once per week.
- It begins before age 25, stops when you are asleep, or you have a family history of the same thing.
When in life does hyperhidrosis start?
Hyperhidrosis usually starts before the age of 30. When hyperhidrosis develops after the age of 30, it is called Late Onset Hyperhidrosis.
What causes hyperhidrosis?
Hyperhidrosis may run in families, and one of the genes for inheriting it has been identified. (5)
You can also have hyperhidrosis due to medicines, illnesses etc. But this type is called secondary hyperhidrosis. In secondary hyperhidrosis treatment would be aimed at the condition causing the sweating, not at the sweat glands and ducts, which are the target with treatment for hyperhidrosis.
How do anti-perspirants work to control sweat in hyperhidrosis?
Anti-perspirants work by blocking the sweat duct, called the eccrine gland shown in the diagram as a sweat pore. This sweat pore is different than a hair follicle, which is the classic 'pore' plus oil gland. The eccrine gland is also different from the body odor glands, called apocrine glands. Apocrine glands open into hair follicles primarily in the groin and armpits.
Eccrine glands are found on all areas of body skin and they open directly to the skin surface. The function of sweat production is to help with your body's thermoregulation (temperature control); evaporation of sweat on your hot skin is cooling.
The active ingredients in antiperspirants are metallic aluminum salts.
The original aluminum salts were either aluminum chloride or aluminum chlorhydroxide. These ingredients can be irritating to skin, especially in higher concentrations. Another less irritating aluminum salt is aluminum zirconium tetrachlorohydrex glycine (meaning the aluminum is coupled with zirconium instead of chloride).
Do anti-perspirants stop sweat?
No. Aluminum salts do not stop sweat production; sweat is still produced from the gland, but it can’t exit through the duct to the skin. The blockage is temporary which is why anti-perspirants need to be reapplied either daily or weekly depending on the type of product.
Anti-perspirants are medicines and there are different concentrations of active ingredients.
Anti-perspirants are regulated strictly by the FDA as drugs (3). There are 18 different aluminum salts allowed to claim anti-perspirant effectiveness. Some are more commonly found in commercial anti-perspirants than others.
The most common aluminum salts in anti-perspirants are:
- aluminum chloride,
- aluminum chlorhydroxide, and
- aluminum zirconium tetrachlorohydrex glycine.
The maximal percent of anti-perspirant active ingredient allowed by the FDA for each of the 18 salt varies according to FDA regulations.
In general, the concentration ranges for non-prescription anti-perspirant products run from 15 to 25%.
These active ingredients are combined with other ingredients to create a final product, and it is the overall formulation that determines effectiveness and/or skin irritation.
When you are looking at a store shelf full or seemingly endless options for anti-perspirants, the results really boil down to the different concentrations of the active ingredients listed on the labels. Read the labels and looks for that information! Then look for the claim "all day" or "extra effective" - Dermatologist Dr. Cynthia Bailey
Is there really a difference between "all day protection" and "extra effective" anti-perspirants?
Yes. The FDA strictly regulates the claims that an anti-perspirant can make, and these must be substantiated by testing.
Products that have demonstrated standard effectiveness will provide a 20% reduction in sweat over 24 hours. You will see them labeled with statements such as “all day protection,” “lasts 24 hours,” etc.
If 30% reduction of sweat over 24 hours has been demonstrated, then a claim of “extra effective” can be made.
What is a clinical strength anti-perspirant?
Interestingly, when you go anti-perspirant shopping, you are more likely to see products labeled as “clinical strength,” and I do not see a strict definition for this in the FDA regulations. When I read the ingredients listed on these products, I find that within an anti-perspirant brand, this term is usually reserved for their products with higher concentrations of their chosen active aluminum salt(s). It doesn't make sense beyond marketing in my opinion. For example, at my local store, I've found:
- Secret Original Solid which contains 15% aluminum zirconium tetrachlorohydrex gly.
- Dove’s Cool Care Essentials Anti-perspirant contains 15.2% aluminum zirconium tetrachlorohydrex glycine.
“Clinical Strength” anti-perspirants:
- Secret Clinical Strength Solid contains 20% aluminum zirconium tetrachlorohydrex Gly,
- Dove Clinical Protection contains 15 to 20% aluminum zirconium tetrachlorohydrex glycine, and
- Certain Dri “Prescription Strength Clinical” contains about 12% aluminum chloride
Are there stronger prescription Anti-perspirants?
Yes, commercial made products are made by the company Person and Covey. They are aluminum chloride solutions formulated in anhydrous alcohol, which increases effectiveness while minimizing irritation. That said, I have prescribed these for years and tried them myself. They can be quite irritating.
Drysol is the strongest, commercially-available prescription anti-perspirant and contains 20% aluminum chloride. Other prescription anti-perspirants in the 10-30% range can be prescribed by your doctor but are not premade commercial products. They must be made individually for you by specialized pharmacies (called compounding pharmacies). This practice is becoming rare.
Another milder prescription anti-perspirant made by Person and Covey is Xerac AC, which contains 6.25% aluminum chloride. This sounds low, but even at this concentration, it is effective and available only by prescription. It is less irritating than Drysol or custom, higher-concentration products and is often the first prescription product that your doctor may recommend.
How do you use prescription antiperspirants?
Drysol and prescription anti-perspirants are used differently than non-prescription products. They are to be applied to the affected area nightly for a week or so until sweat is reduced (meaning the ducts are blocked). After that, the solution is often applied only once or twice a week.
The solution is to be washed off six to eight hours after application. Use must be postponed if irritation develops.
Is Botox only for people with hyperhidrosis, or can people who are just really sweaty use it, too?
Botox, and other similar injectable 'neurotoxins' reduce sweat production in general, regardless of whether it is excessive. They are only FDA-approved for use in people suffering from hyperhidrosis. However, Botox can reduce sweat from baseline production to as little as 25 or even as low as 10% (4). I personally am a big fan of neurotoxin injection treatment of axillary hyperhidrosis. It's the only thing that's saved my clothing!
How long does Botox sweat treatment last?
Reduction in sweat can last from 3 to 9 months before you need another treatment. It lasts about 8 to 9 months for me. Some people can see reduction in sweat for up to 16 months. (5)
How does Botox in the armpits help prevent/reduce excessive sweating?
Hyperhidrosis happens because the nervous system is not functioning correctly in an area of skin with a lot of sweat glands. The sweat glands are turned on by a very specific type of nerve connection using a signal that involves secretion of the nerve’s chemical neurotransmitter (a chemical messenger that talks specifically to nerves). Botox is a 'neurotoxin' and it blocks this neurotransmitter from turning on the sweat gland at the connection site only in the area where it was injected. The blockage lasts for the time that the treatment lasts. After that, your body makes a new connection that needs re-blocking by another series of injections. That's why the effects of Botox wear off!
There are other neurotoxin brands such as Xeomin and Dysport that are FDA approved and used by dermatologists to treat hyperhidrosis. Again, the blockage is not permanent which is why Botox wears off, and you need additional treatment when excess sweating returns - drats!
At what point should someone see their doctor for excessive armpit sweat?
If you are unable to adequately control excessive armpit sweating with over-the-counter commercial anti-perspirants then your dermatologist can help. They can prescribe stronger anti-perspirants or you can consider Botox injection treatment. Interestingly, hyperhidrosis is not often the main reason that brings a person into my dermatology office, it's usually a secondary question during their appointment. The good news is that we have ways to help.
Does controlling armpit sweat stop body odor?
No! Darn but no it does not. Armpit body odor happens when normal skin bacteria breakdown secretions from the apocrine glands, releasing smelly substances. Body odor is an entirely different subject. Many anti-perspirants will also claim to be both an anti-perspirant and "deodorant". The deodorant function is usually the inclusion of something that acidifies the skin such as alcohol to help discourage bacteria. Deodorants are also usually loaded with fragrance to disguise body odor, which, in my opinion, doesn't really work.
My tip to help reduce body odor is to use a zinc pyrithione cleanser in the armpit during the shower. Zinc pyrithione reduces the presence of microbes using a non-antibiotic mechanism of action. I find that this helps to reduce body odor. I use my Foaming Zinc Cleanser that I also use as a dandruff shampoo and as a way to help fight fungal acne. It's a great product to have in the shower to serve multiple needs.
What's the bottom line with excessive armpit sweat?
Reading labels and using a strong non-prescription anti-perspirant is the first line of treatment. Prescription anti-perspirants are available and injectable neurotoxins work well. Body odor can still be a problem even without sweat and using a pyrithione zinc cleanser is a great way to help reduce body odor.
- James Doolittle, Patricia Walker, Thomas Mills, Jane Thurston, Hyperhidrosis: an update on prevalence and severity in the United States, Archives of Dermatological Research, December 2016, Volume 308, Issue 10, pp 743–749
- James, W. D., Berger T. G, Andrews’ Diseases of the Skin, Clinical Dermatology, 12th edition, Copyright 2016 Elsevier, Inc., Pages 771-772
- Amanda-Amrita D. Lakraj, Narges Moghimi, and Bahman Jabbari, Hyperhidrosis: Anatomy, Pathophysiology and Treatment with Emphasis on the Role of Botulinum Toxins, Toxins (Basel). 2013 Apr; 5(4): 821–840. Published online 2013 Apr 23. doi: 10.3390/toxins5040821 PMCID: PMC3705293 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3705293/
- Hodge BD, Brodell RT. Anatomy, Skin Sweat Glands. StatPearls. London: StatPearls Publishing; 2019.