Surprising things your body odor is trying to tell you

Worried about body odor? You're not alone. For 98 percent of the world, the daily battle against smelly armpits is real, a study cited by Smithsonian magazine revealed. The remaining 2 percent actually have odor-free pits. Despite being blessed with a gene that blocks armpit stink, though, the vast majority of them still get up every day and slather on deodorant. Of course, not all body odor emanates from the armpits. And if breath mints and body sprays are any indication, we're not keen on any kind of body odor.

Nevertheless, B.O. is not all bad. For one thing, it can offer actionable clues as to the state of our health. In fact, scientists have long associated certain diseases and conditions with distinct body odors (via 2014 study published in the Journal of Psychological Science). That makes sense when you consider body odor results from chemicals in our sweat glands interacting with bacteria on our skin, as Beverly Hills-based dermatologist Tsiporra Shainhouse told Health Digest. And those chemicals reflect our body chemistry, which can reveal much about our health. So what surprising things might your body odor be trying to tell you? Here's what the experts say.

An increase in body odor can be a sign of an overactive thyroid

Your thyroid is a small, butterfly-shaped gland located in the front of your neck. Tiny but powerful, it produces hormones that help regulate your body's metabolic functions, including how fast you burn energy. If the thyroid produces too much of these hormones (a condition known as hyperthyroidism), your heart rate, respiration, and digestion can speed up, Brenda Swanson-Biearman, a doctor of nursing practice and assistant professor at Duquesne University's School of Health Science, told Health Digest. As a result, your body temperature can become elevated, which can lead to increased sweating. The more you sweat, the more your sweat glands interact with the bacteria on your skin. The result? More body odor.

Of course, increased body odor is just one symptom of hyperthyroidism, Dr. Swanson-Biearman continued, and a subtle one at that. But if you're noticing it along with increased sweating, heat sensitivity, and an unusually rapid heartbeat, it is worth checking in with your physician, particularly if these symptoms are accompanied by swelling at the base of the neck, which can indicate your thyroid is inflamed.

A change in male body odor may be related to changing testosterone levels

"For males and females at any age, any change in 'stinkiness' can be a sign of hormonal changes," Katherine Boling, a family practitioner at Mercy Medical Center's Personal Physician Site in Lutherville, Maryland, told Health Digest. For example, if a man notices his body odor has become less pronounced, it could be a sign his testosterone levels are decreasing. But never is this phenomenon more pronounced than in tween-aged boys. When your sweet-faced "baby" boy suddenly begins emanating a brand new and distinctively not-sweet smell — particularly from his armpits — it's safe to assume he's entered puberty. 

Now brace yourself, because this is just the beginning. A boy's hormone levels, and particularly testosterone, rise markedly throughout puberty, Dr. Boling revealed to Health Digest. Testosterone causes the sweat glands to produce not only sweat, but also oils, which also interact with bacteria on the skin. Bottom line? When you first catch a whiff, there's no going back. Your boy is growing up.

Women's body odor can change throughout the month

Menstruation, ovulation, and pregnancy all come with their own subtle changes in body odor, Katherine Boling, a family practitioner at Mercy Medical Center's Personal Physician Site in Lutherville, Maryland, revealed in an interview with Health Digest. Many of these changes in smell can be attributed to fluctuations in reproductive hormones. 

The same is true of perimenopause, which refers to the years when a woman's body gradually becomes less fertile along the way toward menopause. Since perimenopause involves a decrease in estrogen relative to testosterone, and testosterone is associated with more pungent body odor, one sign perimenopause has begun is a gradual but persistent increase in the pungency of a woman's body odor

Still, every woman experiences perimenopause in her own unique way. Some don't even realize what's been happening until they look back and realize it's been over a year since Aunt Flo paid a visit. For women wondering how many childbearing years they have left, you should know common signs include increasingly irregular periods, thinning hair, frequent headaches, and weight gain, particularly around the waist.

This is why your post-workout body odor smells like ammonia

Ever finish up a CrossFit class and gotten a whiff of ammonia? That smell may have come from you. Gross as it may seem, there's often a logical explanation, board-certified family physician Nikola Djordjevic told Health Digest. In response to physical exertion, your body produces nitrogen, which your kidneys metabolize and excrete via urine. The more intense your workout, the more nitrogen that's produced. When that's more than your kidneys are accustomed to processing, some ends up coming out in your sweat. And when nitrogen is excreted through sweat, it becomes ammonia. Hence, the unmistakable smell. 

But as Dr. Djordjevi told us, it's generally not a problem unless you notice that ammonia smell at other times. In that case, it could be a sign that your kidneys aren't functioning optimally. That said, kidney disease typically presents with other symptoms, including blood in the urine, swelling of the feet and ankles, and a noticeable decrease in appetite. Since kidney disease can be serious and requires medical testing, you should consult your doctor if you have any of these symptoms in addition to ammonia body odor.

Smell like rotten eggs? Your body odor may be a warning from your liver

In the course of everyday life, we're exposed to toxins. Some come from our own bodies, including the toxic byproducts of digestion and respiration. Others, though, we voluntarily expose ourselves to, such as alcoholic beverages, medications, and food additives. Still others, such as VOCs and PFCs, are simply present in the environment.

The liver's job is to process and rid the body of toxins, board-certified family physician Nikola Djordjevic told Health Digest. Therefore, if liver function is compromised, toxins can build up in the body. That can result in an unpleasant odor emanating from the skin and/or the breath, which some describe as musty and others compare to rotting eggs. 

That being said, liver problems seldom present with body odor as the sole symptom. Rather, they typically involve a yellowing of the skin or eyes (jaundice) accompanied by abdominal swelling, upper-right quadrant pain, loss of appetite, nausea, mental confusion, and difficulty concentrating. If you notice these symptoms — with or without musty or rotten-egg body odor — a doctor's visit is warranted.

Fishy body odor is an unmistakable sign of this condition

An overall fishy body odor usually means only one thing, board-certified family physician Nikola Djordjevic told Health Digest: a metabolic disorder known as trimethylaminuria in which the body can't metabolize a substance called "trimethylamine." Trimethylamine is a gas used in industrial manufacturing, but it's also a byproduct of digestion. Produced by gut bacteria, it's then metabolized into a harmless substance and excreted from the body. In rare cases, the body is unable to metabolize triethylamine. When triethylamine builds up, it results in a telltale "fishy" body odor emanating from the skin, urine, breath, and even the reproductive fluids.

This fishy smell may be the only symptom, but it's such an unpleasant symptom that, chances are, you're going to check in with your doctor ASAP. Most doctors would immediately recognize trimethylaminuria, although a definitive diagnosis requires a urine test. While there's no cure for trimethylaminuria, it can be controlled through dietary changes, including cutting out seafood and foods containing choline, nitrogen, or sulfur.

Localized fishy body odor points to certain infections

While trimethylaminuria can cause an all-over fishy body odor, certain vaginal infections can cause a more localized fishy smell, Cynthia Wesley, a North Carolina-based obstetrician-gynecologist, told Health Digest. The most common of these is bacterial vaginosis (BV), she explained. BV occurs when the good and bad bacteria of the vagina become imbalanced. That can be precipitated by anything that would tend to disrupt the vaginal flora, including douching or having sex with multiple partners, although BV is not transmitted sexually. 

A slightly less common cause of fishy vaginal odor is trichomoniasis, aka trich, which is a sexually transmitted infection — and a common one at that. In addition to the distinctive fishy odor, both BV and trichomoniasis can cause external irritation and discharge. Both also require antibiotic treatment. Accordingly, Dr. Wesley strongly encourages any woman who is experiencing fishy vaginal odor to schedule an appointment with her gynecologist.

Some medications can cause changes in body odor

If you've been noticing changes in your body odor, it's possible the cause is a medication you're taking, Katherine Boling, a family practitioner at Mercy Medical Center's Personal Physician Site in Lutherville, Maryland, explained to Health Digest. That's because many medications are known to affect body odor. For example, many commonly prescribed antidepressants are associated with increased sweating and can thus cause an increase in body odor. The same is true of many migraine medications.

The sleep supplement valerian has a smell that's been described as reminiscent of dirty socks, smelly cheese, and vomit. Since some of its metabolites are excreted through the skin, those taking it should be prepared for their skin to smell, well, like dirty socks, smelly cheese, and/or vomit.

If the chemical smell of some chemotherapy drugs seems to linger on the skin, it's because they do. As they're metabolized, some of the metabolites get excreted through the skin. Drugs that affect hormone levels, including birth control pills and hormone replacement therapy, can also change a person's body odor.

You are what you eat, or at least you'll smell like it

What you eat can have a significant impact on how you smell, at least temporarily, Beverly Hills-based dermatologist Tsiporra Shainhouse told Health Digest. Some foods, such as meat, garlic, and curry, can leave a distinctive odor on your skin as they're digested. Others, like asparagus, can affect the smell of your urine. When your body breaks down onions, sulfur-like compounds are excreted through your skin, throughout your digestive tract, and through your breath, with the effects lasting sometimes for days. And when you drink alcohol, it's metabolized by your body into the chemical acetate, which has a signature sweet smell that's easily noticed by others on both your skin and your breath.

By the same token, some foods may actually enhance body odor. For example, citrus fruits like lemons and oranges may help limit muskier smells that might be lingering on skin by helping "flush water through your body," David Colbert, a New York City-based dermatologist and internist told Women's Day. Further, a 2014 study published in Journal of Food Science revealed that eating raw apple, parsley, spinach, or fresh mint can help neutralize "garlic breath."

This sweet odor can signify diabetes

High blood sugar levels, a condition known as hyperglycemia, can cause sweet-smelling breath that some describe as "fruity." Although hyperglycemia can be caused by a number of conditions and circumstances, it's the "hallmark of diabetes," Omiete Charles-Davies, a medical doctor and surgeon who leads the team at onedoctor.app, told Health Digest. That's why breath that smells sweet, in the absence of other explanations, has long been considered an early warning sign of diabetes, the doctor revealed.

Additionally, a 2014 study published in Journal of Breath Research found a link between a sweet-smelling chemical marker in the breath of children with type 1 diabetes and the buildup of potentially harmful chemicals in the blood when insulin levels are low. In so doing, the researchers have opened the door to identifying a rapid, non-invasive test that can effectively diagnose type 1 diabetes before serious illness sets in.

Already been diagnosed with diabetes? Don't ignore "acetone breath"

In diabetes, the body's inability to make or use insulin effectively means that sugar is stuck circulating in your blood, rather than getting to your cells for energy. Without glucose unavailable for energy, the body begins to burn fat instead, which creates a buildup of acids in the blood known as ketones. That buildup of ketones is associated with what Omiete Charles-Davies, a medical doctor and surgeon, refers to as "acetone breath." Acetone is the active ingredient in nail polish remover and has a distinct, fruity-chemical odor. 

If you've been diagnosed with diabetes, and notice your breath has begun to smell like acetone, you might be suffering from diabetic ketoacidosis, Dr. Charles-Davies revealed to Health Digest. This is especially true if you know you've missed an insulin shot, or if you feel tired, weak, excessively thirsty, and confused. This condition is a medical emergency, the doctor added, and requires quick resolution by a qualified physician.

Stress causes a new brand of body odor

In the 1980s, Dry Idea ran television ads that included the tagline, "Never let them see you sweat." Now maybe a really effective antiperspirant can keep armpit sweat to a minimum and maybe it's possible to fake a calm demeanor. But it's time someone told you: You've got a "tell" — and that's the way you smell when you're experiencing stress

"We have two different types of sweat glands in our bodies, eccrine and apocrine," New York City-based dermatologist Joshua Zeichner told Health Digest. "But only apocrine responds to stress, and when it does, it has a pronounced odor." And depending where those apocrine glands are located (some are in your groin, for example), it's going to be difficult to keep them from doing their sweaty thing. 

In addition, Katherine Boling, a family practitioner at Mercy Medical Center's Personal Physician Site in Lutherville, Maryland, told us  that the release of cortisol in response to stress also affects body odor because, along with adrenaline, it pumps you up for "fight or flight" by raising your body temperature and causing your muscles to tense. The result? More stinky sweat.

This mistake leads to "unmistakably terrible" body odor

Over the years, Katherine Boling, a family practitioner at Mercy Medical Center's Personal Physician Site in Lutherville, Maryland, has had a number of female patients come see her with the complaint of a terrible smell emanating from "down there." The moment they walk into her office, Boling already knows exactly what the problem is — before she's even performed an examination. "Did you forget to remove your tampon the last time you had your period?" the doctor will ask, but she already knows the answer is a resounding, if somewhat mortified, "yes." And an exam confirms as much. 

"It is an unmistakably terrible smell and it permeates the entire room," Boling divulged to Health Digest. "It happens more than you might think." Luckily, none of Dr. Boling's patients have suffered lingering consequences as a result of their forgetfulness. That may be attributable to their coming in to see her as soon as they notice the smell — and that's what Dr. Boling would recommend for all women in that situation. Don't hesitate; run to see your doctor. And try to remember to remove your tampons in a timely fashion, of course.

You may produce a distinctive body odor when you're sick

Although certain diseases and conditions are known to result in characteristic odors emanating from the body of a person who's sick, could it be that all sickness are associated with some level of smell?  Katherine Boling, a family practitioner at Mercy Medical Center's Personal Physician Site in Lutherville, Maryland, told Health Digest that whenever she's cared for sick patients in the hospital, she's noticed that those with fever all have a distinctive body odor.

Interestingly, Christopher Dietz, a physician and medical director for MedExpress, told Fatherly"Humans have pretty good noses, and there is research to suggest that people who are sick, or are about to get sick, smell differently than people who are healthy." Although fevers did not come into play, one study also demonstrated similar findings, as Mats Olsson, an experimental psychologist at the Karolinska Institute in Sweden, told CNN. He explained, "On average, people smell more aversive when they're sick."

This may actually act a form of protection. "When we're healthy and we smell something unpleasant, we're likely to avoid it," Dietz revealed. "Which, in this case, helps keep us away from germs that can cause sickness."