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march 2023 | 5 Minute Read 

It’s no secret that glycolic acid is touted as a holy grail skincare ingredient by many and has gained virality on TikTok for being a multi-purpose “hack” product that can be used on the face, scalp, feet and armpits.  

When it comes to the armpits, many creators have recommended it either as a replacement for deodorant, or to brighten underarm darkness. However, although many have tried it and claimed success, many others, me included, have warned against its use on the underarms as it can make the condition worse and CAUSE severely darkened armpits! 

Why is it that glycolic acid can work for some and cause worse hyperpigmentation for others? In this blog, I’ll share why glycolic acid for underarms is not such a good idea and whether it can be used safely or if should it be avoided altogether. 

glycolic acid


Chances are you are no stranger to glycolic acid and have either used it or have seen people on TikTok and YouTube recommending it for your skin, hair and body care routines. Let’s break it down: 

Glycolic acid is a type of alpha-hydroxy acid (AHA) that is derived naturally from certain fruits, beets and sugarcane. It is a water-soluble, colorless, and odorless substance that is commonly used in skincare products for its exfoliating and brightening properties 

Glycolic acid works by breaking down the bonds between dead skin cells, allowing them to be easily removed from the surface of the skin. It also has antibacterial properties and has been proven to kill acne-causing bacteria at certain concentrations. 

Glycolic acid has one of the smallest molecules compared to other AHAs which means it can penetrate deeper into the skin 

That sounds like a good thing, right? Well, not always and I’ll explain why. 


Popular glycolic acid formulations that are being used to treat darkened armpits were simply not formulated for that area. Both the pH level and % concentrations were not designed to treat dark spot pigmentation in this highly complex area of the body. 


We all know the saying, too much of a good thing is a bad thing. The same is true when it comes to hyperpigmentation treatments in the underarms. Over-exfoliating is a big problem when it comes to hyperpigmentation treatments as it’s very easy to over-do it and sometimes you may not realize it right away. 

When glycolic acid is applied to the skin, it helps to remove dead skin cells and unclog pores, which can lead to a brighter and smoother appearance. However, in the armpit area, this exfoliation can also remove the top layer of skin, weakening the skin barrier and resulting in pigmentation-causing irritation and inflammation. 


The first mistake people make when using glycolic acid on the underarms, is using a concentration that is far too high for the sensitive and delicate underarm area (e.g. 7% or above). I even see 30% AHA acids being used on the underarms! This is surely asking for trouble. 


The next problem is the frequency of use. I see a recommended hack of using glycolic acid instead of deodorant, however this is not a good strategy. In order to have the intended odor-eliminating effect, you would need to use it every day. However, if you’re using a strong 7%+ concentration, using it every day will certainly lead to irritation, inflammation and rashes that cause darkened armpits. 


Another reason why glycolic acid may cause darkening of the armpits is due to its pH level. Glycolic acid is a highly acidic ingredient, with a pH level of around 3.5-4. Your underarm pH is around 6.5. 

This pH disparity and the acidity of glycolic acid can disrupt the skin’s natural pH balance, which can lead to irritation and inflammation. In response to this irritation, the skin may produce more melanin, which can cause the skin in the armpit area to become darker. 


Some people have sworn that glycolic acid worked for them and in some cases it truly can, however for some, it can make the condition even worse in the long run. 

rebound hyperpigmentation

Those with melanin-rich, skin of color and sensitive skin are prone to something that is called: rebound hyperpigmentation. It occurs when aggressive and harsh products (such as 7% glycolic acid) are used to treat pigmentation issues in the delicate areas of the body. This can happen from DIY and chemical brightening treatments in the underarms, bikini line and intimate areas.  

Initially you do see results at first as the brightening treatment is working on the surface of the skin, however these aggressive brightening treatments will stimulate melanin production and in the long term, the pigmentation returns. In some cases, it can be even worse than before due to the increased levels of irritation and inflammation. 


So, what can you do to prevent glycolic acid from causing darkened armpits? Firstly, we’ve established the skin on the underarms is different from anywhere else on the body, and as such, you need to refrain from putting facial skin products on the underarms. 

For this reason, I always recommend avoiding popular chemical exfoliating products that were formulated for the face on the underarms. 

Further to this, avoid DIY treatments like lemon and sugar scrubs as they can be equally harsh. 

is glycolic acid ever okay on the underarms?

Yes, only if it was used in a product that was developed specifically for the underarms, meaning the brand has formulated at a very low concentration and at the right underarm pH to avoid irritation. 



Slow, steady and gentle wins the race when it comes to treating darkened armpits. When planning your course of action for treatment options, you should first look and see if there are specialized products for the area you’re treating. 

A few years ago, it would have been difficult to find products that treat darkened armpits that were also specifically formulated to be gentle and effective for the delicate underarm area. This is exactly what inspired me when I was developing my underarm brightening system. 

It’s a two-step system that combines a kojic acid soap, formulated at a gentle and safe dose to brighten, followed by my niacinamide deodorant that also contains brightening alpha arbutin.  

These two products work synergistically, combining a wash-off and leave-on system so they can be used every day and do not cause additional irritation on the underarms that leads to rebound pigmentation. 


Glycolic acid is a wonderful skincare ingredient; however, I warn against its use in the underarms for its potential to cause serious irritation, inflammation, rashes and recurring hyperpigmentation that can be worse. Instead, look for underarm brightening products formulated specifically for this purpose that you know will be gentle and safe enough to use without side effects. 

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All content found on this website is created for informational purposes only. The content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this Website. 


Clean beauty industry maven and product developer Madame Sweat (Mary Futher) founded kaia naturals after spending 20 yearsworking for global beauty companies. She now shares advice on modern hygiene etiquette for grooming, hosting, home and travel on Instagram, TikTok and her popular blog called The House of Hygiene.