If your thyroid–a butterfly-shaped gland in the neck that helps control metabolism–is underactive, you may experience weight gain, constipation, cold sensitivity, or fatigue (hypothyroidism). If it's overactive, you may lose weight quickly, sweat a lot, have a fast heartbeat, or feel nervous or moody (hyperthyroidism). Luckily, thyroid treatments are often effective.

Featured Stories

19 Signs Your Thyroid Isn’t Working Right
Crabby, gaining weight, and unable to concentrate? It could be a problem with that little gland in your neck.
11 Celebs With Thyroid Disease–and How They Knew Something Was Wrong
Don’t ignore extreme exhaustion and unexplained fluctuations in weight. They could signal trouble with a tiny organ in your neck that keeps your metabolism humming along.
9 Things You Need to Know About Your Thyroid
Got weight gain or unexplained fatigue? That butterfly-shaped gland in your neck may be to blame. Here's what it controls, how to tell if it's healthy—and how to keep it that way.
15 Thyroid Cancer Facts Everyone Should Know
Thyroid cancer diagnoses are on the rise, and most cases are in younger adults. Here's what you should know about detection, treatment, and recovery.
If You Get Frequent Headaches, You May Want to Have Your Thyroid Tested
New research has found that people with headache disorders (especially migraines) are more likely to be diagnosed with hypothyroidism.

More on Thyroid

I Survived Thyroid Cancer—but Dealing With the Side Effects Has Been Harder Than I Ever Imagined

Writer Christine Coppa had her thyroid removed because of cancer. Here, she explains what life is like without this important gland, her struggle with weight gain and mood changes, and what she wants others to know about surviving the big C.