Anyone who has ever woken up to armpits that randomly smell like an old Subway sandwich, and/or Googled “can you change the smell of your BO?”, welcome! Today, fellow smelly people, we’re investigating the common causes of BO, and what to do about them. To sniff out the answers, we turned to Ruvini Wijetilaka, MD, of Parsley Health.
“First, just some background info about sweat glands,” Dr. Wijetilaka says. “There are two major types: apocrine glands and eccrine glands.”
Most of our sweat glands are eccrine glands. They occur all over the body, with the exception of a few areas, like lips and nail beds. These ones produce watery sweat to help us cool down when our body temps rise—like when we’re working out or, say, boiling in a heat wave.
Apocrine glands develop after puberty in areas with lots of hair, like armpits and groin. These guys secrete (sorry, there’s really not a better word to use) a milky fluid when our bodies react to an emotion, like stress or excitement.
Sweat itself isn’t the cause of bodily stinkiness, however. “Sweat is usually odorless when secreted from the sweat gland,” Dr. Wijetilaka says. “Bacterial breakdown of secreted sweat is the primary mechanism leading to body odor.” Basically, BO happens when sweat meets bacteria on our skin and the more bacteria, the stronger the smell. Fun fact: bacteria particularly love sweat from the apocrine glands because it contains lots of protein. Yum.
“The main things that influence body odor are diet, exercise, and intense emotion/stress that entails sweating,” Dr. Wijetilaka says.
She gives the following examples:
- Diet (e.g., garlic, onion, curry, alcohol ingestion)Medications (e.g., penicillin, bromides)
- Toxins (e.g., heavy metals)
- Stress/elevated cortisol
Dr. Wijetilaka adds that poor gut and oral health can also lead to body odor. “Remember, if the gut microbiome isn’t properly working, this could affect the skin, as there is a correlation between the gut and skin microbiome,” she says. And since bad breath-causing oral bacteria affects the gut microbiome, she recommends getting our teeth cleaned professionally two times a year.
So, does this mean it’s possible to change our BO? Not exactly. “You can’t change your body odor, but you change certain lifestyle habits to help mitigate the smell,” Dr. Wijetilaka says. An obvious action is to wash our stinky bits daily, which helps get rid of the bacteria that cause the smell. Removing hair in those areas can also help reduce odor, she says, as hair traps odor. Several studies (note: subjects were all men) found that shaving or waxing armpits followed by washing with soap improved the effectiveness of just washing with soap for up to three days post-shave.
Interestingly enough, chewing on parsley can also improve body odor, Dr. Wijetilaka says. It usually takes two to four weeks to see a difference.