Maybe you noticed an offensive odor wafting off your workout top as it went airborne toward the hamper. Or perhaps you caught a bitter whiff of yourself on a run, thanks to a sideward gust of wind. Or, you just feel generally encased by bad body odor. Whatever the stank-uation, if your sweat is giving off pee-yew vibes, you’ve probably got some questions about why you smell so bad and what you can do about it.
To help you get to the bottom of the sweat-induced BO, we called up a team of experts to put together this guide. Ahead, learn about why you sweat in the first place, plus the five most common causes of sweat gone sour.
Remind Me: Why Do We Sweat?
Sweating is an evolutionary response designed to help regulate your body temperature. When the body’s internal temperature starts to rise above the 98 degrees Fahrenheit it generally sits at, the brain tells the eccrine glands that it’s time to start cooling you down, explains holistic physician Dr. Sony Sherpa, M.D. How do the glands do this? By producing sweat.
When you sweat, the eccrine glands release a mixture of water and some salts, she explains. There are two to four million of these glands located throughout the body, but they are most dense in your armpits, palms, and soles of your feet.
Read More: How To Dress For Success At The Gym
“When this liquid evaporates, which happens when excess heat being produced by your body turns the sweat to vapor, it takes some of the body heat with it, helping regulate the body’s core temperature and keep you cool,” Sherpa explains. (Scientifically, this part of the process is known as heat vaporization).
Also important to know: The body doesn’t just produce sweat when it’s hot out or the air is humid. It also produces sweat during stressful situations. Eccrine sweat glands, as well as a second type of sweat gland known as apocrine glands, also get activated when there’s a rush of adrenaline and other stress hormones throughout the body, notes Sherpa. This activation attempts to preemptively keep the body comfortable and cool during times of stress (think fight or flight).
Common Causes Of Stinky Sweat
A number of different factors influence your odor. Here are the main culprits.
1. You’re Stressed
Stress sweat, generally speaking, has more of an odor than the sweat you produce in response to heat and humidity. The culprits here are those apocrine glands, which secrete sweat in response to stress, but not heat. The apocrine sweat glands are larger than the eccrine sweat glands, and populate the parts of the body with denser layers of hair follicles, like the pubis and armpits, explains Sherpa.
The presence and growth of body hair in these regions causes the sweat that comes out of apocrine glands to be richer in proteins and fats (also known as lipids), she says. When this sweat combines with the pre-existing bacteria around these regions, the result is smellier than regular eccrine sweat, explains registered dietitian Melissa Baker, R.D.N., an expert with FoodQueries.
The Fix: “Adding any stress-reducing activity into your routine can be helpful,” says wellness expert and board-certified dermatologist Zein Obagi, M.D., founder of ZO Skin Health in Beverly Hills. What qualifies as stress-busting varies from person to person, but common stress-relief activities include gentle exercise (think yoga and walking), meditation, grounding, and journaling. Chilling out your stress response also chills out your sweat-induced B.O.
Read More: 6 Physical Signs You’re Way Too Stressed
Because the presence of bacteria in and around these apocrine gland-jammed regions contributes to the odor, “making changes to your personal hygiene practices can have a noticeable impact,” says Obagi. Specifically, washing more frequently, using chemical-free soaps, detergents, and deodorants, wearing breathable clothing, and swapping skivvies regularly can all really make a difference.
2. You’re Snacking On Sulfur-Rich Foods
The common refrain that “what goes in must come out” doesn’t refer exclusively to bowel movements; sometimes what we consume is eliminated from our system via sweat.
One of the main culprits of stink-released-through-sweat? Sulfur compounds. When you consume foods that contain a lot of sulfur, like garlic and onions, you may smell it in your sweat in the days that follow, according to Obagi. “After the compound has been metabolized by the body during digestion, it can get released through your sweat glands,” he says. The odor of these compounds can be a little unpleasant; in fact, it’s reminiscent of rotten eggs.
The Fix: Many foods that are rich in sulfur are also rich in flavor. So while your meals certainly won’t benefit from you cutting out foods rich in sulfur compounds (such as garlic, onions, some cruciferous vegetables, and some spices), your body odor might.
How long it takes the body to metabolize sulfur compounds varies, but on average it takes about two days to move the compounds through your system, Obagi suggests. That’s why he recommends avoiding these sulfurous foods a few days ahead of big events or social outings if you’re concerned.
There is also some research that suggests that the fat in milk, raw apples, parsley, and mint may help the body break down these stink-causing compounds more quickly, hopefully helping to minimize the duration of any eggy stench.
3. You’re Boozing Regularly
This won’t come as a surprise to anyone who’s ever hit a Sunday morning group fitness class after a night out, but consuming an excessive amount of alcohol can contribute to wonky body odor.
The reason: The body metabolizes alcohol differently than other foods and drinks because it views booze as a toxin, says Baker. As a result, the body goes into overdrive trying to metabolize alcohol and get it out of its system as soon as possible. The thing is, the body can only metabolize about one standard serving of alcohol per hour.
So, when you imbibe heavily, your body leans on another process—known as oxidation—to help get alcohol out of your system. During oxidation, the body breaks the toxins in alcohol down into diacetic acid, carbon dioxide, and water, explains Baker. The body can then excrete these particles through your urine, breath, and, yep, sweat. “When the diacetic acid is excreted through sweat glands, it changes your sweat composition, which can alter its smell and lead to a different—often stronger—odor than usual,” she says.
The Fix: Imbibe mindfully. According to the U.S. Dietary Guidelines, that means one drink maximum per day for women and two for men.
Whether you stick to those recommendations or choose to consume more, staying hydrated can help minimize the next-day sweat stink, according to Baker. Drinking plenty of water alongside your alcoholic beverages keeps you better hydrated, which then helps reduce the concentration of diacetic acid in your sweat later.
4. You’re Nutrient Deficient
Nutrient deficiencies can cause a number of unsavory symptoms, such as slow wound healing, hair loss, generalized fatigue, and irregular heartbeat. One more to add to the list? Stinky sweat. Deficiencies in zinc and vitamin C, in particular, have been linked to changes in body odor, according to Baker.
Both zinc and vitamin C play a role in immune system regulation, Baker explains. As a result of the impact they have on the immune system, deficiency in either may lead to an imbalance in the body’s microbial flora, which can then impact body odor. “Vitamin C deficiency may also impair the body’s ability to break down certain substances, which can affect the way sweat smells,” she adds.
The Fix: The solution here is two-part. First, talk to a healthcare professional, advises Baker. “Nutritional deficiencies can be caused by underlying health issues, rather than being just a direct effect of what you are (or aren’t) consuming,” Baker says. As such, if your sweat reeks, she recommends talking to a professional, getting your nutrient levels checked, and ruling out any other possible underlying cause.
Beyond that, Sherpa recommends eating a wide variety of fruits and vegetables. “Choose to consume a balanced diet rich in fruits, vegetables, whole grains, and lean proteins will help you avoid deficiencies, as well as support overall well-being.”
5. Your Hormones Are Fluctuating
How your sweat smells may also be connected to changes in hormone levels, according to registered dietitian and nutritionist Krutika Nanavati, Ph.D. “Hormonal fluctuations, such as those that occur during puberty or menopause, can affect sweat production and scent,” she explains. (For that same reason, hormone disorders can also impact body odor.)
The same is true throughout a woman’s menstrual cycle. “The degree to which body smell is impacted may vary between individuals,” says Sherpa. “However, studies do suggest that fluctuations in hormone levels throughout the menstrual cycle indeed influence body scent.”
Read More: 9 Lifestyle Tweaks To Make For Healthier Hormones
Check this out: In one small study published in the journal Ethnology, researchers out of the Charles University in Prague monitored a group of women’s armpit scent throughout their menstrual cycles. Researchers found that their sweat smelled most strongly during menstruation and hypothesized that it could be a biological signal of fertility to potential mates.
Not to mention, some people also experience hot flashes and night sweats right before or during. their period. These can lead to excessive sweating, which can make body odor more noticeable, adds Nanavati.
The Fix: Ultimately, the best thing you can do about scent changes during that one week of the month is to accept them. You have little control over the natural hormonal ebbs and flows of your cycle, says Nanavati.
You may also take comfort in the fact that research shows that estrogen and progesterone hormone levels can impact how just sensitive your schnoz is to smells. As such, it’s possible that your body odor isn’t actually perceptibly different to the people around you during your period, but rather that you’re just more sensitive to it.
The Bottom Line
Obviously, stinky sweat can be an uncomfortable conundrum to deal with. If you’re struggling to figure out the root cause of any sudden changes in your scent or can’t seem to kick an unusually intense odor, check in with a healthcare professional who can help you dig into any underlying culprits you might be missing. Otherwise, rest easy knowing that last night’s garlic bread was well, well worth any eggy sweat you might be dealing with today—and that your sweat should be back to normal before you know it!