12 Signs Your Thyroid Isn't Working Right

1. 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.”

2. 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.

3. 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.

4. 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."

5. 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.

6. 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.

7. 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.

8. 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.”

9. 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).

10. 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.

11. 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.

12. 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.