Back to Basics: An Introduction to the Thyroid

By: Mary Shomon, Thyroid Expert

Average Read Time: 6 minutes

Metabolism’s Master Gland

The thyroid is your master gland of metabolism. It has a crucial job: producing the hormone that helps ensure that oxygen and glucose get into your cells. Every cell, organ, tissue, and gland needs that oxygen and glucose to function. Your brain needs thyroid hormone for you to think clearly. Your heart needs thyroid hormone to beat properly. Your skin, hair, nails, digestion, sex drive need thyroid hormone…you get the drift.

So, even though your thyroid is a small, butterfly-shaped gland in your neck, it plays a major role in your health. But how does it all work?

When it’s working right, it is a perfectly balanced system. Your pituitary gland knows when you need thyroid hormone. It then releases a hormone called TSH (Thyroid Stimulating Hormone), which goes to your thyroid and says, “Make more thyroid hormone!”

Your thyroid gland gets the message and goes to work. The thyroid uses iodine from your diet and combines it with tyrosine to manufacture thyroid hormones (mainly T4 and T3), which are then released into your bloodstream. While it travels around the bloodstream, the T4 is converted into T3, the active thyroid hormone. T3 is like the key to the door. It helps ensure that cells get the oxygen and glucose they need to do their job.

When there’s too much thyroid hormone circulating, the pituitary drops down on production of TSH to tell your thyroid, “Slow down on making that thyroid hormone.” T4 and T3 production slows down, and things return to balance. It’s like your home thermostat. Set it to 70, and the heat or air conditioning will go on and off to keep you at the right temperature.

However, when the thyroid is not working properly, it can become a significant health issue.


Sometimes your thyroid isn’t producing enough thyroid hormone. (Or there is a problem along the way, like your pituitary isn’t doing its job, or the T4 isn’t converting to T3, or the cells are pushing back against receiving the oxygen and glucose.)

The resulting situation is called hypothyroidism – an underactive thyroid.

Hypothyroidism has many causes. A few of the most common include:

In the U.S., the most common cause of an underactive thyroid is, however, an autoimmune disease called Hashimoto’s thyroiditis. With Hashimoto’s, your immune system gets confused. Instead of targeting the usual villains like bacteria and viruses, it decides that your thyroid doesn’t belong, and starts to attack it with proteins called antibodies. Eventually, these Thyroid Peroxidase (TPO) antibodies can slow down your thyroid, make it shrink, and even destroy its ability to function, making you hypothyroid.

Without oxygen and glucose, your cells are cut off from their power source, and everything slows down. As a result, signs and symptoms of hypothyroidism start to develop. Just a few of the common symptoms include:


Sometimes your thyroid produces too much thyroid hormone. The resulting situation is called hyperthyroidism – an overactive thyroid.

Hyperthyroidism has many causes:

The most common cause of an overactive thyroid is, however, an autoimmune condition called Graves’ disease. With Graves’ disease, your immune system gets confused and starts hammering your thyroid with proteins called antibodies, specifically the Thyroid Stimulating Immunoglobulin (TSI) antibodies. They stimulate your thyroid and tell it to make more thyroid hormone. Your gland pumps out more and more thyroid hormone, making you hyperthyroid.

Flooded with too much oxygen and glucose, your cells are like a car when you have pedal to the metal. Everything speeds up, too quickly. The signs and symptoms of hyperthyroidism manifest. Just a few of the common symptoms include:

up next: Hyperthyroidism and Graves’ Disease 101

Other Thyroid Conditions

There are a few other thyroid conditions that don’t fit neatly into the hypothyroid or hyperthyroid category. Thyroid nodules are common, and found in all types of thyroid issues. Most are benign, but some can produce thyroid hormone, or impair your gland’s ability to function.

Thyroid cancer is rare, but on the rise, and cancerous nodules are usually treated with surgery to remove the entire thyroid gland.

Several types of thyroiditis (viral, bacterial, and autoimmune inflammatory conditions in your thyroid gland) can cause pain, sensitivity in the neck, and trigger both hypothyroid and hyperthyroid symptoms.

But let’s be clear: most paths lead to hypothyroidism because the treatment for cancer, problematic nodules, and resistant thyroiditis is usually surgery. And after you’ve lost your thyroid gland, you end up hypothyroid.

Treating Hypothyroidism

Hypothyroidism is treated medically by replacing the hormone that your body is missing. This is called thyroid hormone replacement therapy. In the conventional medical world, that means levothyroxine, a synthetic version of the T4 hormone. (You may know the brands of levothyroxine tablets, Synthroid and Levoxyl, or the liquid capsule form, Tirosint.)

On the integrative front, if you’re hypothyroid, you’re more likely to be on a combination treatment of synthetic T4 and T3. The synthetic T3 hormone is liothyronine. The brand name in the U.S. is Cytomel, and some patients also take prescription compounded T3 medication. T3 can help people who are low in this active thyroid hormone, and resolves symptoms better for some patients.

Another option for thyroid hormone replacement is the drug called natural desiccated thyroid (NDT). This prescription drug is made from the dried thyroid gland of pigs, and has been on the market to treat hypothyroidism for more than 100 years. NDT includes natural forms of both the T4 and T3 hormones, and some patients prefer this medication and get better symptom relief. Holistic and integrative doctors are more likely to prescribe it, compared to conventional doctors. NDT is controversial, however. Some insurance, HMO, and public health programs refuse to include it as a treatment option or cover the cost.

Conventional medicine doesn’t address the autoimmunity, and this is where the integrative and holistic approaches shine. Alternative therapies such as low-dose naltrexone, selenium supplementation, and special diets are some of the ways that the immune dysfunction can be addressed.

Treating Hyperthyroidism

Hyperthyroidism is typically treated three ways. Antithyroid drugs – mainly methimazole (Tapazole) and, less commonly, propylthiouracil (PTU) – can be taken to slow down the thyroid gland. Sometimes, you will go into remission after taking these medications. Radioactive iodine (RAI) is a liquid or pill form of iodine that delivers radioactivity specifically to your thyroid gland. Finally, surgery to remove all or part of your thyroid gland can be a treatment. As noted earlier, the permanent treatments usually end up with you becoming hypothyroid for life and requiring daily thyroid hormone replacement treatment.

Conventional medicine doesn’t address the underlying Graves’ disease, but integrative practitioners have had some good results lowering antibodies with low-dose naltrexone, herbal remedies, special Graves’ disease diets, and other approaches.

What Next?

We’ve touched on just a few of the many issues related to hypothyroidism and hyperthyroidism and their treatments. If there’s anything we can tell you going forward, it’s that you should take to heart the following three pieces of advice:

  1. Learn everything you can about your condition and your options. Information is power with any health condition, and it lets you be an effective advocate.
  2. Partner with a great healthcare provider for your thyroid diagnosis and treatment. The right provider can make all the difference.
  3. Put it all together! You will hear some practitioners say, “Thyroid disease is easy. Just take a pill every day, and you’ll be fine.” For most thyroid patients, medical treatment is only one facet of a multi-part, total approach to feeling vibrant, healthy, and happy. Your nutritional status, the foods you eat, your level of activity, how you manage stress, your attitude, and your support networks are all crucial to living well after a thyroid diagnosis.

Ready to start putting together your own total approach? Let’s get started! Next stop: The Beginners’ Bundle.


About the Author

Mary Shomon is a patient advocate and New York Times bestselling author of 13 books on health. Mary has been researching, writing and teaching about thyroid disease, hormonal health, weight loss, and autoimmune disease for two decades. In addition to her books, you can find her writing at and, and catch her PBS Healthy Hormones television specials. Follow Mary on Facebook.