If you’ve always been a good sleeper but suddenly 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 still tired after a full night’s sleep, or the need to sleep more than usual, you might have an underactive thyroid, in which your body doesn’t produce enough hormones.
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,” says Dr. Gupta.
Changes in bowel habitsTheDman/iStock
Frequent constipation could be a sign of an underactive thyroid. “Thyroid hormones also play a role in keeping your digestive track running,” says Dr. Gupta. “If you produce too little, things get backed up.” An overactive thyroid can create the opposite effect. “You’ll experience a regular bowel movement—not diarrhea—but the need to go more frequently, because everything is sped up,” says Dr. Gupta.
Thinning hair, particularly on your eyebrows, is a common sign of thyroid disease. 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. When thyroid hormones are imbalanced, too much hair rests at one time, which means hair looks thinner, notes EverydayHealth.com.
Sweating at random timesstokkete/iStock
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.
Clothes that fit tighter than usualPhotoTalk/iStock
If your jeans feel snug but you swear you haven’t changed your eating or exercise habits, an underactive 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.
Feeling ravenous but not gaining weightmichellegibson/iStock
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 are losing weight instead of gaining,” says Gupta.
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.
Too much energy (like you've guzzled 5 cups of coffee)digitalskillet/iStock
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.
Craving an afternoon nap every dayCentralITAlliance/iStock
Daytime tiredness or the urge to nap can be signs of an underactive thyroid. “The body needs these thyroid hormones to produce energy,” says Dr. Gharib.