19 signs your thyroid isn’t working right

The thyroid, a butterfly-shaped gland in the neck, can have a dramatic impact on a huge variety of bodily functions, and if you're a woman over 35 your odds of a thyroid disorder are high—more than 30 percent, by some estimates.

At least 30 million Americans have a thyroid disorder and half—15 million—are silent sufferers who are undiagnosed, according to The American Association of Clinical Endocrinologists. Women are as much as 10 times as likely as men to have a thyroid problem, says integrative medicine specialist Dr. Robin Miller, co-author of The Smart Woman’s Guide to MidLife & Beyond.

Located above the Adam's apple, your thyroid produces thyroid hormone (TH), which regulates, among other things, your body's temperature, metabolism, and heartbeat. Things can start to go wrong when your thyroid is under- or over-active. If it's sluggish, it produces too little TH; amped-up and it produces too much. What causes your thyroid to go haywire? It could be genetics, an autoimmune attack, pregnancy, stress, nutritional deficiencies, or toxins in the environment, but experts aren't entirely sure. Because of thyroid hormones far reach in the body—from brain to bowels—diagnosing a disorder can be challenging. Here's how to tell if your thyroid could be on the blink.

You're exhausted

Feeling tired and having no energy are issues associated with lots of conditions, but they're strongly linked with hypothyroidism, the disorder that's the result of too little thyroid hormone. If you're still tired in the morning or all day after a full night's sleep, that's a clue that your thyroid may be underactive. Too little thyroid hormone coursing through your bloodstream and cells means your muscles aren't getting that get-going signal. “Fatigue is the number one symptom I see,” says Miller. “It’s the kind of fatigue where you’re still tired in the morning after a full night’s sleep—that’s a clue that you’re not simply sleep deprived; your thyroid may be underactive.”

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You're feeling down

Feeling unusually depressed or sad can also be a symptom of hypothyroidism. Why? It's thought that the production of too little thyroid hormone can have an impact on levels of "feel good" serotonin in the brain. With an underactive thyroid turning other body systems down to "low," it's not surprising that your mood might sink there, too.

You feel jittery and anxious

Anxiety and "feeling wired" are associated with hyperthyroidism, when the thyroid gland is making too much thyroid hormone. Flooded with consistent "all systems go" messages, your metabolism and whole body may spin into overdrive. If you feel like you just can't relax, your thyroid may be "hyper."

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Your appetite or taste buds are altered

An increased appetite can be a sign of hyperthyroidism when too much thyroid hormone may have you feeling hungry all of the time. The only upside is that the "hyper" part of the disorder typically offsets the caloric impact of an increased appetite so the end result isn't weight gain.

An underactive thyroid, on the other hand, can mess with your sense of taste and smell.

Your brain feels fuzzy

Sure, it could be caused by sleep deprivation or aging, but cognitive functioning can take a hit when your thyroid is out of whack. Too much thyroid hormone (hyperthyroidism) can cause difficulty concentrating and too little (hypothyroidism) may cause forgetfulness and general brain fog. “When we treat patients for hypothyroidism, they are often surprised at how fast their brain fog goes away and how much sharper they feel,” Miller says. “Many women think it’s just something that comes along with menopause when it really is a sign of a thyroid problem.”

You've lost your interest in sex

Having little or no desire in the sack could be a side effect of a thyroid disorder. Too little thyroid hormone could be a contributor to a low libido, but the cumulative impact of other hypothyroidism symptoms—weight gain, low energy, and body aches and pains—could also play a part.

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You're feeling all fluttery

That fluttery feeling you're having may be heart palpitations. It can feel like your heart is actually fluttering or skipping a beat or two, or beating too hard or too quickly. You may notice these feelings in your chest or at pulse points in your throat or neck. Heart flutters or palpitations can be a sign of too many thyroid hormones flooding your system (hyperthyroidism).

Your skin is dry

Skin that's dry and itchy can be a symptom of hypothyroidism. The change in skin texture and appearance is probably due to slowed metabolism (caused by too little thyroid hormone production), which can reduce sweating. Skin without enough moisture can quickly become dry and flaky. Likewise, nails can become brittle and may develop ridges.

Your bowels are unpredictable

People with hypothyroidism sometimes complain of constipation. The disruption in hormone production has likely caused a slowdown of digestive processes.

“There’s just no motility in your gut,” Miller says. “This is one of the top three most common symptoms of hypothyroidism I see.”

On the reverse side of the spectrum, an overactive thyroid gland can cause diarrhea or more frequent bowel movements, which is why they're symptoms of hyperthyroidism.

Your periods have changed

Longer menstrual periods with a heavier flow and more cramps can be a sign of hypothyroidism, where thyroid hormones are in short supply. Periods may be closer together.

With hyperthyroidism, high levels of TH cause menstrual irregularities in a different way. Periods are shorter, farther apart and may be very light. “I always ask my patients about their cycles and if they’re regular,” says Miller. She finds a strong link between irregular cycles and thyroid problems. And if periods are extra-heavy, she checks for anemia, too.

You have painful extremities or muscles

Sometimes you stub a toe or work out too hard—that kind of pain can be explained away. But if you have mysterious or sudden tingling or numbness—or actual pain—in your arms, legs, feet, or hands, that could be a sign of hypothyroidism. Over time, producing too little thyroid hormone can damage the nerves that send signals from your brain and spinal cord throughout your body. The result is those "unexplained" tingles and twinges.

You have high blood pressure

Elevated blood pressure can be a symptom of a thyroid disorder. Both hyperthyroidism and hypothyroidism have been fingered as culprits. By some estimates, people with hypothyroidism have two to three times the risk of developing hypertension. One theory is that low amounts of thyroid hormone can slow heart beat, which can affect pumping strength and blood vessel wall flexibility. Both may cause a rise in blood pressure.

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Your thermostat is on the fritz

Feeling cold or having chills is associated with hypothyroidism. The system slow-down caused by an underactive thyroid means less energy is being burned by cells. Less energy equals less heat.

On the other hand, an overactive thyroid puts energy-producing cells into overdrive. That's why people with hyperthyroidism sometimes feel too warm or sweat profusely.

You're hoarse or your neck feels funny

A change in your voice or a lump in your throat could be a sign of a thyroid disorder. One way to check is to take a good look at your neck to see if you can detect any signs of thyroid swelling. You can do a physical check of your own thyroid at home with these directions from The American Association of Clinical Endocrinologists:

Using a hand mirror, watch your throat as you swallow a drink of water. You're looking for any bulges or protrusions in the thyroid area, which is below your Adam's apple but above your collarbones. You may want to try this several times to get a hang of where your thyroid really is. If you see anything that's lumpy or suspicious, see your doctor.

Your sleep schedule is messed up

Want to sleep all of the time? It could be hypothyroidism. A sluggish thyroid can slow bodily functions down to the point where sleeping (even in the daytime) seems like a brilliant idea.

Can't sleep? It could be hyperthyroidism. An overactive thyroid can cause anxiety and rapid pulse, which can make it hard to fall asleep or even wake you in the middle of the night.

You've gained weight

Going up a few dress sizes can be caused by so many things that it's unlikely your doctor will look at weight gain alone as a potential thyroid disorder symptom. However, weight gain is one of the top reasons women show up in Miller’s office for a thyroid checkup. “They’ll tell me that they aren’t eating any more than usual, but they’re gaining weight,” she says. “They are exercising, but they are getting nowhere. They can’t lose it.” It’s almost always due to an underactive thyroid, she says.

On the other end of the scale, a sudden weight loss can signal hyperthyroidism.

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Your hair is thinning or falling out

Dry, brittle hair that breaks or falls out can be a sign of hypothyroidism. Too little thyroid hormone disrupts your hair growth cycle and puts too many follicles into "resting" mode, resulting in hair loss—sometimes all over your body including at the outside of your eyebrows. “Lots of my patients come in and tell me that their hairdresser sent them,” says Miller. “They’ll say, ‘My hair stylist said I’m losing my hair and I needed to go ask my doctor about my thyroid.’ The hair salons are more aware of thyroid problems than some doctors!”

An overactive thyroid can also do a number on your hair. Hair issues due to hyperthyroidism typically show up as thinning hair just on your head.

You have trouble getting pregnant

If you've been trying to have a baby for an extended period of time with no luck, an under- or over-active thyroid could be a contributing factor. Difficulty conceiving has been linked to a higher risk of undiagnosed thyroid problems.

Both hypothyroidism and hyperthyroidism can interfere with ovulation, which impairs fertility. Thyroid disorders are also linked to pregnancy complications.

You have high cholesterol

High levels of low-density lipoprotein (LDL) cholesterol that haven't responded to diet, exercise, or medication have been linked to hypothyroidism. Elevated levels of the "bad" cholesterol can be caused by an underactive thyroid and are cause for concern. Untreated hypothyroidism can lead to heart problems, including an enlarged heart and heart failure.

Get your thyroid tested

If you have one or more of these symptoms and suspect it's your thyroid, see your doctor and ask for a thyroid stimulating hormone (TSH) test, Free T3, and Free T4 tests, says Miller. Based on test results, your symptoms, and your physical exam, you may be prescribed synthetic hormones. Testing and treating a thyroid disorder takes a bit of trial-and-error so expect to visit the doctor a few times before the dosage is right.

Push for thyroid treatment

Expect to have to be your own advocate when it comes to your thyroid. Some doctors may be resistant to a thyroid diagnosis, although the American Associated of Clinical Endocrinologists narrowed the TSH range for acceptable thyroid function from 0.5-5.0 to 0.3-3.04 in 2003. That means more women fall into a range that can be treated. “Find a doctor who treats the person, not just the lab tests,” says Miller. “If you’re feeling better at a certain dosage—that should carry just as much weight as the lab results.”

This article originally appeared on Health.com.