Why Do Your Armpits Smell Bad? Causes and Solutions

Your armpits smell when the bacteria on your skin mix with the sweat your body produces. While having smelly armpits from time to time is a common occurrence, there are some underlying conditions or other factors that can contribute to the odor.

You have about two to four million sweat glands in your body. These glands are primarily eccrine and apocrine sweat glands, with quite a few in your armpits.

Your apocrine sweat glands are typically the ones associated with smelly armpits and that odorous sweat smell. Although the liquid these glands secrete is odorless, once it comes in contact with the bacteria on your skin, it can develop a smell.

While having armpit odor on occasion is normal, some underlying conditions or other factors can contribute to excessive or frequent odor. These include:

• Hyperhidrosis: If you sweat excessively, you could have a medical condition known as hyperhidrosis. This condition affects about 5% of the population and can lead to smelly armpits.
• Menopause: Some people will experience postmenopausal hyperhidrosis, a type of secondary hyperhidrosis that occurs during the transition into menopause. This condition causes the glands to sweat excessively, which can cause increased armpit odor.
• Eating certain foods: The foods you eat can affect your gut and lead to an unpleasant odor in your armpits. Onions and garlic are common culprits, but other foods can contribute to the smell.
• Stress or anxiety: Being stressed or anxious can cause you to sweat more than usual and lead to a smell in your armpits. Research shows that up to 32% of people with social anxiety disorder experience secondary hyperhidrosis.
• Underlying medical conditions: If you have liver disease, kidney disease, or diabetes, you may notice more odor in your armpits. A rare genetic disorder known as trimethylaminuria can also cause a strong, fishy body odor.
• Certain medications: Sometimes, the medications you take can cause an odor in your armpits. For example, certain antibiotics, pain relievers, antidepressants, and chemotherapy drugs can worsen body odor.

When managing underarm sweating and odor, the first line of treatment is an antiperspirant. These products control how much sweat you produce and are available over-the-counter in clinical strength and from a healthcare provider in prescription strength.

The best way to use an antiperspirant is to apply it to totally dry skin before bed. Applying it to moist skin can cause irritation. You may also want to consider shaving or waxing your armpits. One study found that this could significantly reduce armpit odor because it is easier to clean waxed or shaved skin.

It can be helpful to manage your stress and anxiety. This will help with sweating and ultimately reduce odor in your armpits. Try using deep breathing and other relaxation techniques. Yoga, mindfulness, meditation, and progressive muscle relaxation also help reduce sweat and could eventually lead to fewer instances of smelly armpits.

If using antiperspirants and managing stress and underlying health conditions does not alleviate excessive sweating and armpit odor, talk to a healthcare provider about more advanced treatment options. Here are some possibilities:

• Botox injections: These injections treat excessive sweating by temporarily reducing the amount of sweat you produce. It may take a few days before you see results. When used under the arms, Botox can reduce sweating for three to 10 months.
• Topical gel: The prescription medication Sofdra (sofpironium) is applied to the skin and reduces how much sweat your body can make. It’s approved by the U.S. Food and Drug Administration (FDA) and is available by prescription. The gel can be used by people as young as 9 years old who have primary hyperhidrosis in their underarms.
• Medicated cloths: Skin cloths known as Qbrexza (glycopyrronium) are FDA-approved to control sweat and odor. A dermatologist (a medical doctor specializing in skin conditions) can prescribe them. To use, simply wipe one pre-moistened medicated cloth on your underarms once a day.
• Microwave thermolysis: This is an in-office procedure during which a dermatologist uses a device that destroys sweat glands with heat to reduce sweating. It usually takes one or two office visits to see results. The device can help remove odor and may remove hair.
• Sweat control patch: This patch is left on for three minutes and contains sodium that interacts with the water in your sweat. Essentially, this causes an injury to your sweat glands, which causes them to stop working for two to four months.
• Oral medications: A dermatologist can prescribe several medications that make it hard for your body to sweat. It’s important to avoid hot environments, as your body will struggle to cool itself effectively, which can lead to a heat-related illness.
• Surgeries: Several different surgeries can help control sweating and, ultimately, underarm odor. Due to the risks associated with these procedures as well as their permanence, these treatments must be reserved for severe cases of odor and sweating.
• Portable sweat machine: This device, known as an iontophoresis machine, is sometimes used on the underarms but is technically approved for use on the hands and feet. People use the machine for 20-30 minutes, two to five times a week, to reduce sweating. However, it may not be the most effective option for underarm sweat.

In addition to addressing any underlying conditions like hyperhidrosis, diabetes, or menopause, you can take a few steps to help further prevent armpit odor. Here are some things to consider:

• Wash your body after physical activity
• Use antibacterial soap when needed
• Change out of wet clothes after swimming or sweating
• Avoid spicy, onion-heavy, or garlic-rich foods 
• Wear shirt inserts that prevent sweat from getting on your shirt; you can change them when they become sweaty
• Choose breathable or moisture-wicking clothing
• Shave under your arms frequently

Your apocrine sweat glands are usually the ones associated with smelly armpits. When you sweat, these glands release an odorless liquid that then interacts with bacteria on your skin, forming an odor.

Often, excessive sweating (hyperhidrosis) is the cause of strong or frequent armpit odor. Underlying health conditions, such as diabetes, liver disease, and trimethylaminuria, can also lead to increased odor.

To manage and prevent smelly armpits, start with an effective antiperspirant as well as daily bathing, breathable clothing, and shaving. You can also talk to a dermatologist about advanced treatments like Botox, topical gels, and medicated cloths. In extreme cases, surgery is also an option.