Why do so many of us get an armpit rash and irritation from certain antiperspirants and deodorants? It's a frustrating question with a simple answer. In this (extensively researched) video, Carpe cofounder Kasper Kubica dives into why it's so easy to get a rash or burn in your armpits from antiperspirants and deodorants; and what you can do to get back to a pain free underarm. Let us know in the comments what questions you'd like us to answer next about a burning armpit or anything else!

Tired of being too sweaty? Try the sweatstopping products scientifically optimized to get you dry and keep you dry at https://mycarpe.com

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Uter, W., Johansen, J. D., Börje, A., Karlberg, A.T., Lidén, C., Rastogi, S., Roberts, D., & White, I. R. (2013, July 27). Categorization of fragrance contact allergens for prioritization of preventive measures: Clinical and experimental data and consideration of structure–activity relationships. Wiley Online Library. Retrieved September 16, 2021,
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Every day I see so many people posting photos of armpit rashes that they got from deodorants or antiperspirants, and this keeps happening! What is it that they’re putting in these deodorants and these antiperspirants that’s causing these rashes?

So my name is Kasper Kubica; I’m the cofounder of Carpe, which makes sweatstopping products for all over the body. And I’ve been studying deodorants and the science of sweat for about seven years now. So I’m not a doctor – this is not medical advice – but I study this a lot and I’m excited to talk about it.

In this video, we’re going to cover:
Intro (00:00)
Why deodorant rashes are so common (00:30)
What types of deodorant rashes there are (01:24)
What most often causes the rashes (02:15)
What you can do about it (03:53)

Why are Deodorant Rashes so Common?

So it turns out that deodorants and antiperspirants are among the most common cosmetics to cause rashes, to give any sort of irritation or reaction. There’s basically two reasons for this: One is that the skin in your armpits is uniquely sensitive and soft and thin, and the second is that it’s occluded – meaning that whatever you put there kind of gets trapped there by your underarms all day.

So this means that even if you’re using something that wouldn’t give you a reaction on another part of your body that’s maybe more exposed, underarm skin is uniquely predisposed to really suss out any allergies or irritations that you may have to a particular ingredient.

Maybe you’re allergic to eucalyptus oil and you’ve used a eucalyptus shampoo for a while and you’ve never had a reaction; now you use a deodorant with eucalyptus oil and you have a rash. That makes perfect sense, right? Because with the shampoo, you’re washing it off, it’s not sticking around. With the armpit deodorant or antiperspirant, it’s staying there, it’s getting rubbed in, it’s occlusive, and that skin is super sensitive.

So deodorants, regardless of who you are, are very likely to be the product that lets you discover you have some kind of skin allergy.

What Types of Rashes are There?

There are four types of allergic reaction, commonly agreed – this is kind of debated, like, how do you classify allergies. But broadly speaking, you’ve got irritant contact dermatitis and then four types of allergic contact dermatitis. The two that matter are Type I and Type IV.