13 Thyroid Symptoms to Watch Out For

Updated: Mar. 16, 2022

The thyroid, a butterfly-shaped gland in the neck, produces hormones essential for metabolism and brain activity. Symptoms of a thyroid problem are often vague, but if you notice any of the following signs persisting, or have more than one, endocrinologists recommend seeing a doctor to request a simple blood test to gauge your hormone levels.

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Sleep changes

If you’ve always been a good sleeper but recently find you can’t snooze through the night, it could signal a thyroid problem. An overactive thyroid pumps out certain hormones (triiodothyronine, known as T3, and thyroxine, known as T4) in excess, which can overstimulate the central nervous system and lead to insomnia, says Hossein Gharib, MD, a Mayo Clinic endocrinologist.

On the flip side, if you still feel tired after a full night’s sleep (or need to sleep more than usual), you might have an underactive thyroid, in which your body doesn’t produce enough hormones. Everyone should know these important thyroid facts.

Woman at a table in a dark room with head on hand.

Sudden anxiety

If you’ve never struggled with anxiety but start to feel consistently anxious or unsettled, your thyroid might be hyperactive. Too many thyroid hormones often cause patients to feel jittery or anxious unrelated to anything specific, says Ashita Gupta, MD, an endocrinologist at Mount Sinai Roosevelt Hospital in New York City. “There’s more brain stimulation so it excites you to the point where you don’t feel good about it,” she says. Adopt these habits for a healthy thyroid.


Changes in bowel habits

Frequent constipation could be an underactive thyroid symptom. “Thyroid hormones also play a role in keeping your digestive tract running,” says Dr. Gupta. “If you produce too little, things get backed up.”

An overactive thyroid can create the opposite effect: diarrhea.

Man checking his receding hairline in the mirror.

Thinning hair

Thinning hair, particularly on your eyebrows, is one of the many thyroid symptoms to watch out for. An underactive or overactive thyroid throws off your hair growth cycle, says Dr. Gupta. Usually, most of your hair grows while a small portion rests, however, when your thyroid hormones are imbalanced, too much hair rests at one time. This causes you hair to look thinner. Make sure you know these silent signs of thyroid cancer.

Man at desk checking out a sweat mark on his shirt.

Sweating at random times

Excessive sweating when you’re not exerting yourself is a common sign of a hyperactive thyroid. “The thyroid regulates the body’s energy production. Higher than normal hormone levels mean your metabolism is revved up, which causes people to feel overly warm,” says Dr. Gupta.

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Unusual weight gain

If your jeans feel snug but you swear you haven’t changed your eating or exercise habits, an under active thyroid might be to blame. “Lack of hormones decreases metabolism and calorie burning, so you may see gradual but unexplained weight gain,” says Dr. Gharib.

Man in jeans stretching out the loose-fitting waistband with his hand..

Feeling ravenous but not gaining weight

On the other hand, if you’re suddenly able to squeeze into smaller-size clothes that haven’t fit in years—without a major change to your diet or workout regimen—you may have an overactive thyroid, which causes an increase in metabolism. “People often report that their appetite is up and they’re eating a lot, but they are losing weight instead of gaining,” says Gupta. These are the foods thyroid experts avoid.

Closeup of man's head cradled in his hand.

Brain fog

When your thyroid isn’t working right, neither is your brain. With an underactive thyroid, some people report feeling a “brain fog,” says Dr. Gupta. Others report experiencing subtle memory loss (such as that “it’s on the tip of my tongue!” feeling), or overall mental fatigue. An overactive thyroid can make it difficult to concentrate.

Large man gripping his crest.

Too much energy (like you’ve guzzled five cups of coffee)

An overload of thyroid hormones speeds up your body processes. “People say they feel like they’ve had too much caffeine or have heart palpitations even when they’re relaxed,” says Dr. Gupta.

Woman with tilted head presses her fingers against her tired eyes.

Craving an afternoon nap every day

Daytime tiredness or the urge to nap can be an underactive thyroid symptom. “The body needs these thyroid hormones to produce energy,” says Dr. Gharib. Don’t miss these healthy habits for a happy thyroid.

Woman presses her hand against her belly.

Out-of-wack periods

Your thyroid also helps control your menstrual cycle, says the federal Office of Women’s Health. If your periods become heavier, longer, or occur closer together, your thyroid might not be producing enough hormones. But if your periods get lighter or occur further apart, an overactive thyroid might be producing too many hormones.

A woman having an ultrasound.

Infertility or miscarriage

Women who have difficulty conceiving with no family history of infertility—or who miscarry in the early stages of pregnancy—should get a thyroid screening, says Dr. Gupta. “Low hormone levels affect ovulation and predispose you to infertility or miscarriage,” says Dr. Gupta. “If you have thyroid disease, [thyroid] hormone supplementation can be very beneficial while trying to conceive and during pregnancy.” Also, be aware of these other health problems that you can blame on your thyroid.

Crawling baby.

Developmental delays in children

Thyroid problems often manifest differently in children, says Dr. Gupta, because kids won’t always be able to express their symptoms. “If you notice that they are growing significantly slower than their peers, complaining about muscles soreness, or if teachers say they’re jumpy and unfocused, that could be a sign that they have low hormone levels, which can affect their development,” says Dr. Gupta.

A handful of pills.

How to treat a thyroid problem

Overactive and underactive thyroid symptoms are both easily treated.

If your thyroid is overactive: One of the most common treatments is iodine ablation or medical destruction of the thyroid gland. It is an alternative to surgery and does require you to be treated with thyroid hormone for the rest of your life. Doctors also prescribe anti-thyroid medication that slows down the production and release of T4 and T3 hormones. Once hormone levels are balanced, patients can eventually stop taking the medicine, says Dr. Gharib. However, if hyperthyroidism is ignored and left untreated, sometimes surgery to remove some or all of the gland is required, according to the Mayo Clinic.

If your thyroid is underactive: This typically requires lifelong treatment with a synthetic thyroid hormone called levothyroxine. The oral medication restores hormone levels and helps reverse symptoms such as weight gain, fatigue, brain fog, and constipation. However, make sure you also look out for these hidden health dangers of a “normal” thyroid.

Reader's Digest
Originally Published in Reader's Digest