The Many Reasons Why One Armpit Can Smell Worse than the Other

• The likeliest reason one of your armpits smells more than the other is because you’re using that arm more often.
• Your underarms sweat and release odor naturally when you do strenuous activity or are hot.
• The best way to prevent body odor is to wear a deodorant, bathe, and change your clothes regularly.

Reasons Why One Armpit Smells More

You’ve used that side of your body more. This is the leading reason for one armpit smelling worse than the other. No one uses each side of their body the same way every day. You could be sweating more on one side than another, and that’s completely normal! For example, carrying something heavy in one arm or leaning against one arm for extended periods could cause one pit to sweat more. Stop armpit sweating by switching things up by using each arm equally. Maybe you swap which arm you hold your bag in or lean against your other arm.

Your one armpit is hairier than the other. Armpit hair can trap sweat and cause odors. If one of your underarms is fuzzier than the other, it may smell more. The less hair your armpits have, the less likely they are to smell. Prevent this by checking each armpit in the mirror after removing the hair, ensuring each pit is nice and smooth.

You forgot to put on deodorant. During your morning rush, perhaps you forgot to put deodorant or antiperspirant on both armpits—it happens! This may be the cause of your one smelly armpit, especially if it’s not something that happens often. Fix your morning whoopsie by putting on more deodorant, making sure to swipe or spray both armpits this time.

You’re experiencing hormonal changes. How you feel mentally and physically can play a big part in how you smell. Believe it or not, one armpit may smell worse than the other if you’re stressed, anxious, or going through puberty. Licensed dermatologist Alina Goldenberg explains that excessive sweating is often “related to stress or anxiety-provoking situations and is the body’s main response to stabilizing your temperature.” Chat with your doctor if the odor doesn’t go away on its own, especially if you're experiencing other hormonal symptoms like acne, weight gain or loss, or fatigue.

You might have a minor infection. You’re more prone to ingrown hairs if you shave or wax your underarms. The action of pulling your skin while removing hairs can cause irritation and possibly lead to ingrown hairs and infections, which may omit an unusual odor. You may have an infection if your armpits are red, swollen, or tender. Prevent this by taking a break from shaving and waxing and seeing your doctor.

There’s an underlying condition. In some cases, having a strong odor coming from one armpit and not the other could be a sign of an illness or disease. Diabetes, kidney disease, liver disease, an overactive thyroid, and hyperhidrosis can all cause strange or pungent body odor and excessive sweating. Alina Goldenberg, a licensed dermatologist, recommends “an evaluation with a dermatologist to determine the best combination of treatment for you,” especially if you have any one of these conditions (or believe you may have one).

How can you prevent this?

Use deodorant. An effective and easy way to prevent one armpit from smelling worse than the other is to wear deodorant regularly. Use a stick or spray deodorant every morning to keep yourself smelling clean and fresh throughout the day. Opt for an antiperspirant deodorant to help target sweat glands and prevent excessive sweating and odors.

Bathe regularly. Practicing good hygiene is the best way to prevent body odor. Shower or take a bath at least several times a week, or whenever you’ve done strenuous activity. Scrub your skin with a soapy washcloth to remove body odor-causing bacteria.

Wear clean, dry clothes. The dirt and sweat on your clothes can let off a foul odor, so change them regularly. This is especially important after exercising or being in the heat for long periods of time. Along with this, invest in clothing made of cotton, silk, and wool to help keep your armpits dry and prevent odors.

When to See a Doctor

See a doctor if you experience frequent and extreme body odor. It’s normal to stink every once in a while, especially after working out or being in the sun; however, if you tried the above tactics to prevent body odor and still experience it, it’s likely time to seek help. Intense or abnormal body odor and excessive armpit sweat could be signs of an underlying condition. As licensed dermatologist Alina Goldenberg advises, “It is important to be evaluated by a dermatologist to determine the cause, as there are some cases of excessive sweating which can be secondary to underlying systemic medical conditions (such as hyperthyroidism, pheochromocytosis, and, in rare situations, certain cancers).”