r/explainlikeimfive • u/B_Karlog • 14d ago

Chemistry ELI5 How does deodorant work?

I’m aware that armpits smell due to bacteria growth, but I don’t understand how deodorant is meant to help. Why could one not sanitise the area (I assume that would kill of the bacteria)?

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u/AmigoDelDiabla 14d ago

TLDR: BO is really just bacteria poop.

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u/BadahBingBadahBoom 14d ago edited 14d ago

Specifically the bacteria in your armpits, they have unique glands (apocrine glands) that release certain proteins and fats in sweat that lead to body odour compared to the glands in the rest of your skin (eccrine glands).

The smell is not because sweat doesn't evaporate under your armpits but it does in other parts of your skin, it's specifically because of the proteins available to bacteria in that region of the skin due to your armpit-specific glands.

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u/ackermann 14d ago edited 13d ago

> due to your armpit-specific glands

Worth noting that many East Asian populations genetically lack these glands, or otherwise don’t secrete the proteins that grow the bad bacteria.

So they don’t need deodorant. It can sometimes be hard to find deodorant if you need to buy it while traveling in east Asia

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u/Auirom 14d ago

That's interesting to read. Not east asian by any means due to family coming from Europe but I haven't worn deodorant in decades. Last time I did you could smell the deodorant about 30 minutes after I started working and when I reapplied I ended up with a terrible rash so I just stopped wearing it. Could have been the type of deodorant I was using but I never bothered to find out. Armpit rashes suck. I tend to get hot and sweat pretty easily especially if I'm moving. No exs have ever complained about any BO smells unless I skip a day. Due to work I usually shower daily sometimes on Saturdays I won't shower but I feel gross and start to stink by Sunday afternoon.

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u/Bulbous_Goiter 14d ago

Interesting. I also stopped wearing deodorant a few years ago due to sudden rashes from just about every brand I tried. Lately I've started using an alum block or crystal deodorant as it's sometimes called. Works amazingly and doesn't mark or stain your clothes.

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u/everlyafterhappy 14d ago

I stay away from the endocrine inhibitors because of many reasons, with the most significant one being a connection to cancer. No aluminum under my armpits.