Guide
Why do my armpits smell like onions?
Your sweat doesn’t smell like onions when it comes out. Bacteria on your skin turn part of it into sulfur smells, the same kind of smell as onion and garlic. Some people’s bacteria make more of it than others. Stop the bacteria and you stop the smell.
First, the basics
It’s not your sweat. It’s what bacteria make from it.
Fresh sweat barely smells. Your armpits have a second kind of sweat that’s a bit thicker, and the bacteria living there feed on it.
When they break it down, some of what they leave behind smells like sulfur. That’s the onion note. It has nothing to do with being clean or not.
Researchers at Firmenich in Geneva measured it in 49 people. The women’s sweat held about ten times more of the odorless ingredient that bacteria turn into the onion smell. The men’s sweat leaned more toward a cheesy smell. So if you’re a woman and it smells like onions, that’s very normal.
What makes it worse
Six things that turn it up
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Food
Onion, garlic and strong spices leave sulfur in your body for a while, and some of it comes out in your sweat.
How to tellIt shows up a day after a big meal with lots of garlic or onion.
What to doNothing drastic. It passes in a day or two.
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Stress
Nervous sweat comes from the same glands that feed the onion bacteria. More of it means more smell.
How to tellIt’s worse on busy, tense or nervous days.
What to doUse a deodorant that stops the bacteria, so the extra sweat has nothing to turn into.
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Hormones
Puberty, your period, pregnancy and menopause all change your sweat, and with it the smell.
How to tellIt changed around the same time as a life change.
What to doIt’s normal. The same fix works: stop the bacteria.
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Your clothes
Synthetic fabrics like polyester hold on to smell, even after a wash.
How to tellYour shirt smells before you do, or right after you put it on.
What to doWear cotton or merino against your skin. Wash workout clothes inside out.
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Covering it with perfume
A scented deodorant sits on top of the smell. When the scent fades, the onions are back.
How to tellFresh at 9, onions by 3.
What to doSwitch to one that stops the bacteria instead of covering them.
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Damp or unwashed skin
Deodorant on top of an existing smell, or on damp skin, doesn’t do much.
How to tellIt smells soon after you put it on.
What to doWash with soap, dry completely, then apply.
How to stop it
A simple routine that works
1. Wash your armpits with soap in the shower.
2. Dry them completely. Bacteria love damp skin.
3. Put on a deodorant that stops the bacteria, not one that only adds a scent.
4. Wear breathable fabrics close to your skin.
5. Give it a week. You don’t need an armpit “detox”.
When it’s not the deodorant
When to see a doctor
If the smell is new, strong and doesn’t go away with washing, or you suddenly sweat much more than usual, see a doctor. Those can have causes no deodorant will fix.
How nuud works
Stop the bacteria, not the sweat
nuud is a deodorant cream that stops the bacteria that make the smell. It uses tiny bits of silver to do it, plus zinc oxide that works on the sweat so it doesn’t turn smelly.
No perfume on top, so there’s nothing to fade. One pea-size dab per armpit keeps you fresh for up to three days. You still sweat like normal. nuud stops the smell, not the sweat.
Start clean and dry
Apply after a shower, on dry skin.
Take a pea-size dab
That’s enough for one armpit. More doesn’t work better.
Rub it in
Rub it in until you can’t see it.
Questions
Onion smell questions
Is it normal for armpits to smell like onions?
Yes. It’s one of the most common armpit smells, especially for women. Bacteria turn part of your sweat into a sulfur smell that’s a lot like onion.
Can food make my armpits smell?
Yes. Garlic, onion and strong spices can make your sweat smell more for a day or two. It passes on its own.
Why do my armpits smell even after a shower?
Usually the skin isn’t fully dry, or your clothes are holding on to old smell. Dry completely, put on deodorant, and wear a fresh cotton shirt.
Why does the smell come back during the day?
If your deodorant only adds a scent, the scent fades and the smell comes back. A deodorant that stops the bacteria keeps it from coming back.
Do women’s armpits smell more like onions?
Often, yes. A study by Firmenich found women’s sweat holds about ten times more of the ingredient bacteria turn into the onion smell. Men’s sweat leans more toward a cheesy smell.
Will switching deodorant fix it?
It will if your new one stops the bacteria instead of covering the smell. Give it about a week.