Lots of guys can leave the gym after a beastly workout drenched in sweat, and smell pretty much perfectly fine afterward. Sure, you’ll be soaked, but you probably won’t reek.
But when you’re set to deliver a presentation in front of the entire company? That’s when your perspiration turns seriously putrid.
What’s the difference? Sweat is sweat, right?
Not so fast: Your body actually has two different types of sweat glands, explains George Preti, Ph.D., an organic chemist at the Monell Chemical Senses Center, where he researches the origin of human odors.
Eccrine glands produce the watery sweat that covers your body after a hard run. This sweat develops all over your skin, and cools your body down as it evaporates, whether it's because of exercise or heat.
But your apocrine glands, usually only found in your armpit area, are activated when you’re under psychological stress, explains Preti. This sweat produces a strong, sometimes even sulfurous odor when you’re anxious or scared.
Because stress also activates your body’s sympathetic nervous system, you might also notice your heart racing, sweaty palms, and a dry mouth, says Ramsey Markus, M.D., associate professor of dermatology at the Baylor College of Medicine.
The sweat that we produce when we work out is mostly comprised of water, but the sweat that comes from the apocrine glands has a higher concentration of fat, lipids, and proteins, says Dr. Markus, M.D.
That’s good news for bacteria, who love to feed on that mix, but bad news for the guy sitting next to you: Those bacteria produce fatty acids and ammonia, which creates a strong odor, he says.
While it may reek, stress sweat doesn’t actually produce that much wetness under your pits, Dr. Markus adds. You might just notice it more because of its strong stench. But if you consistently deal with excessive sweating (known as hyperhidrosis), you might experience both too much sweat and too much funkiness, he says, making it twice as uncomfortable. (Here’s why you may sweat more than other guys.)
So what’s the reason behind the raunch? Scientists aren’t sure why apocrine glands switch on the stink, but there might be an evolutionary reason behind it, says Preti. Animals tend to emit an odor when they’re stressed, too. That odor acts as a signal to its peers that something dangerous or fearful is happening, he explains.
Another theory suggests that our ancestors may have developed a similar stress reaction to being attacked by an animal, explains Dr. Markus. Scientists speculate that we may have evolved to produce this odor during stressful situations as a way to ward off predators.
How to Stop Your Stress Sweat
Luckily, there are things you can do to tame your B.O., even if you’re constantly anxious. For one, learning how to calm yourself down in a stressful situation doesn’t hurt. (Use this trick to de-stress in under two minutes.)
But learning how to control those emotions can take some time. Treating the underarm area directly can help you manage the odor and wetness quickly, says Dr. Markus.
That means you can’t let the weeds go untamed: If you don’t really groom your armpits, the excess hair in your underarms can trap the oil and give the bacteria more surface area to feast on the sweat, he explains. (Here’s the best way to trim your armpit hair.)
Then, it’s important to find an antiperspirant that works for you. Aluminum chloride, the active ingredient in most antiperspirants, actually plugs up your sweat glands—whether they’re apocrine or eccrine—and prevents any moisture from reaching your skin.
If you want to manage your odor, using a strong over-the-counter antiperspirant like Certain Dri can help minimize your sweating, and thus your B.O., says Dr. Markus.
If you’re dealing with more odor than wetness, try out the best deodorants for men, or look for an antiperspirant that also has a deodorant in it, suggests Dr. Markus.
Having a hard time finding an OTC product that works? Your dermatologist can recommend prescription solutions like Drysol, which contains a higher concentration of aluminum chloride than an OTC antiperspirant, or even Botox injections in your underarms if you need something stronger, he says.
But Botox can get pricey and the injections aren’t permanent, he says, so don’t write off OTC solutions without testing out a couple of options first. If the B.O. still sneaks up on you after trying several options, talk to your dermatologist. He or she can help you find a treatment that works best for you.
Deputy Editor, Prevention
Alisa Hrustic is the deputy editor at Prevention, where she leads the brand’s digital editorial strategy. She’s spent the last five years interviewing top medical experts, interpreting peer-reviewed studies, and reporting on health, nutrition, weight loss, and fitness trends for national brands like Women’s Health and Men’s Health. She spends most of her days diving into the latest wellness trends, writing and editing stories about health conditions, testing skincare products, and trying to understand the next greatest internet obsession.
