What is the Thyroid Gland?
The thyroid is a butterfly-shaped gland in the front of your neck, just above your windpipe, that makes special chemicals called hormones that control how fast your body uses energy and helps you grow. 1
Where is it Located?
- The thyroid sits in the lower front part of your neck, right above the tube you breathe through (called the trachea) 2
- It weighs about as much as three nickels (15-20 grams) in grown-ups 1
- It looks like a butterfly with two wings (called lobes) on either side of your neck 1, 3
What Does the Thyroid Do?
The thyroid makes hormones that act like tiny messengers telling almost every part of your body how fast to work. 1
Main Jobs:
- Controls your body's energy - like a thermostat that decides how fast your body burns food for energy 1, 4
- Helps you grow taller and makes your bones strong 1
- Helps your brain work better - including memory and being smart 1
- Helps your teeth grow properly 1
- Makes almost every cell in your body work the right speed 4
How it Works:
- The thyroid needs a special ingredient called iodine (found in fish, dairy, and salt) to make its hormones 2
- It also needs iron and selenium (other nutrients from food) to work properly 2, 5
- Your brain sends signals to tell the thyroid when to make more or less hormone 4
What Diseases Can Affect the Thyroid?
When the Thyroid Makes Too Little Hormone (Hypothyroidism):
- You feel very tired and cold all the time 6
- You might gain weight even though you're not eating more 6
- This happens when you don't get enough iodine in your diet 2, 5
When the Thyroid Makes Too Much Hormone (Hyperthyroidism):
- Your heart beats too fast and you feel nervous 6
- You might lose weight even though you're eating normally 6
- Sometimes lumps in the thyroid (called nodules) make too much hormone 7, 8
When the Thyroid Gets Lumps (Nodules and Goiter):
- The thyroid can grow bigger or develop bumps inside it 5, 7
- Most lumps are not dangerous, but doctors need to check them 7, 8
- Not getting enough iodine makes the thyroid grow bigger trying to work harder 2, 5
- This is more common in women, especially as they get older 5, 7
Thyroid Cancer:
- Sometimes the lumps can be cancer, but this is rare 2
- Between 118,000 and 166,000 people have thyroid surgery each year in the United States 2
- Thyroid cancer rates have been increasing, especially in women 2
- Most thyroid cancers can be treated successfully with surgery and special medicine 2
How Are Thyroid Diseases Treated?
For Low Thyroid Hormone:
- Doctors give you a pill with thyroid hormone (called levothyroxine or L-T4) that you take every day 2
- This replaces the hormone your thyroid isn't making enough of 2
For Too Much Thyroid Hormone:
- Doctors can use radioactive iodine medicine that shrinks the overactive parts - this works 98% of the time 8
- Sometimes surgery is needed to remove part or all of the thyroid 8
For Lumps and Cancer:
- Surgery to remove the thyroid (called thyroidectomy) is the main treatment 2
- After surgery, you might get radioactive iodine to kill any remaining bad cells 2
- Then you take thyroid hormone pills for the rest of your life 2
Important Things to Know About Surgery:
- Experienced surgeons who do lots of thyroid surgeries have fewer complications - surgeons who do more than 100 surgeries per year have the lowest complication rate (4.3%) 2
- Sometimes the nerves near the thyroid that control your voice can be injured during surgery, which happens in about 3-5% of cases 2
- Your calcium levels might drop temporarily after surgery because tiny glands near the thyroid (parathyroids) can be affected 2