The good thing to remember is that a little bit of smell is natural, and everyone has been there. “Body odour is caused by bacterial breakdown of sweat,” explains Dr. Shari Lipner, MD, Ph.D., a dermatologist at Weill Cornell Medicine and NewYork-Presbyterian. There are a few main glands that produce sweat: Eccrine and apocrine. But when it comes to B.O., the apocrine gland is the main culprit, explains Dr. Richard Firshein, D.O., a leading expert in integrative and precision-based medicine and founder of Firshein Center. These are the glands in our armpits and groin area, which is why this is where we usually apply deodorant.
But why do humans tend to smell a little raunchy as the day wears on? There are a few reasons.
B.O. is a natural body function
“Body odour is normal,” Firshein says. “There are a lot of reasons people think we have body odour, and they range from the release of pheromones to preventing predators from thinking we might be a good meal. They run the gamut.”
The good news is that even though body odour is annoying, it’s pretty natural. It ramps up during puberty — and (luckily for us!) it happens for the rest of our lives. Still, some B.O. is worse than others for a reason.
You're going through puberty
There's a reason most six-year-olds don't wear deodorant — B.O. gets worse with puberty. Beginning when we're pre-teens, our hormones cause us to begin to sweat more in the armpit and groin area. And, as the University of Wisconsin-Madison puts it, "New hormones produced during puberty cause teen sweat to contain chemicals that aren’t present in childhood. These chemicals produce stronger odours as they break down."
You're eating the wrong foods
Firshein says that there are certain foods we eat that may cause B.O. The worse smells happen when your body can’t properly break down and secrete specific compounds in your food.
Some foods that are known for causing problems are those with sulphur in them, such as red meat, eggs, onions, broccoli, and garlic, Firshein says.
"Each food has a specific type of bacteria, that can produce a slightly different smell," Firshein says. To reiterate: Body odour is caused by bacterial breakdown of sweat, and eating different foods will shift the kinds of bacteria interacting with that sweat. It's like the circle of life, but with sweat and smell.
You're drinking too much
Firshein says that when you drink a lot of alcohol, your sweat becomes more acidic, which will translate into body odour. The more alcohol you drink, the more acidic you may smell (and the more deodorant you may want to roll on!).
Just when you thought stress couldn’t be any more damaging — it can worsen B.O. Stress does not actually cause body odour, but likely worsens it, Lipner explains. Those crazy apocrine glands we talked about activate when you’re under psychological pressure, and stress tends to send your sympathetic nervous system into high gear. “If you have a stressful encounter or a near accident, your smell can get acidic,” Dr. Kristine Blanche, PA.-C., Ph.D. is the CEO of Integrative Healing Center, says. “The body goes into fight or flight, and it changes the whole dynamic within the body, your heart rate will go up, and it there can be changes the different pH of your body, taking you from alkaline to acidic.”
There’s a bigger issue going on with your health
It’s natural for your body odour to change when you hit puberty. But if it’s happening later in life, it could signal of a larger problem with your health, Blanche says.
People who have diabetes may experience more body odour than some people, Firshein notes. Lipner adds that it could be an endocrine disorder such as hyperthyroidism, or even a neurologic condition.
Blanche recommends trying to first mix up what you eat if a drastic change in body odour occurs — see a doctor if the problem persists after that.