Do you have an underactive thyroid?

No appetite but still gaining weight? Or maybe you feel sluggish or cold all the time. An underactive thyroid — or hypothyroidism — could be the reason.

The thyroid plays a big role in how your body functions. When it slows down, your body can feel it in many ways. An underactive thyroid affects everything from mood and energy levels to heart rate and your period.

Having an underactive thyroid can be scary. The good news is that hypothyroidism can be managed with the right treatment.

What’s your thyroid?

Your thyroid is a butterfly-shaped gland. It sits at the base of your neck against and around your windpipe. And it’s responsible for making thyroid hormones. These hormones tell other cells in the body how to use energy.

“Thyroid hormones control our bodies,” says Rajiv Datta, MD. He’s a surgeon at Mount Sinai South Nassau in Oceanside, New York. “They regulate our metabolism, body temperature, heart rate, mental health and weight. Everything is controlled by thyroid hormones.”

Whether you have a new prescription or need a refill, the Optum Store can help you save on your thyroid medication — and have it shipped right to your door.

Symptoms of an underactive thyroid

Hypothyroidism happens when your body doesn’t make enough thyroid hormones. This causes many of your body’s functions to slow down. The symptoms can include:

• Fatigue
• Constipation
• Muscle aches and cramps
• Dry skin
• Swelling around the face
• Weight gain
• Depression
• Slowed heart rate
• Feeling cold or shivering
• Irregular period
• Hair loss (on the head)
• Dry, brittle hair

“Hypothyroidism is like running a car, but the engine is running much slower than we need it to,” explains Dr. Datta. The condition can become serious if it’s not treated.

Who’s at risk for an underactive thyroid?

“Underactive thyroids are about 10 times more likely to impact women than men,” says Alan P. Farwell, MD. He’s an endocrinologist at Boston University School of Medicine in Massachusetts. This is true for most autoimmune diseases, he adds.

Some other causes include:

• Hashimoto’s disease. This autoimmune disease is a common cause of hypothyroidism, says the American Thyroid Association. Antibodies that usually attack bacteria and viruses in your body get confused. And they attack the thyroid instead.
• Thyroiditis. This condition causes inflammation in the thyroid. At first, it releases too much thyroid hormone. But the thyroid eventually becomes underactive.
• Prescription medication. Certain medications may affect your thyroid. These include medications for bipolar disorder, cancer and heart disease. That’s per the National Institute of Diabetes and Digestive and Kidney Diseases.
• Congenital disorder. This condition is often seen in newborns. They may not have a thyroid. Or it’s not fully developed at birth.
• Iodine deficiency. Iodine is important for thyroid function. And not having enough may lead to hypothyroidism.
• Medical procedures. Some people with thyroid nodules or thyroid cancer need to have part or all of the gland removed. This can lead to hypothyroidism. Radiation can also cause physical damage to the gland.

In many cases, there’s no reason for an underactive thyroid. It just happens. This is especially common in women nearing menopause.

Treating the condition

Doctors can often tell that you have an underactive thyroid before you show symptoms. This is because thyroid hormones are in the bloodstream. Your doctor can order a basic blood test to find out more, says Dr. Datta. Certain low hormone levels may point to hypothyroidism.

Your doctor may prescribe a medication known as thyroid hormone replacement. “Thyroid hormone replacement is very similar to the hormones made by your body,” says Dr. Datta. “It’s a very safe medication.” Medications include:

• Levothyroxine
• Liothyronine and levothyroxine
• Desiccated thyroid extract

All 3 treatments successfully ease the symptoms of an underactive thyroid, according to the Endocrine Society.

“It will take a few months [to feel relief],” says Dr. Datta.

So don’t panic if you’re still not feeling great in a week. With the right medication, an underactive thyroid can be easily managed. Visit your doctor to discuss your symptoms and treatment options.

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Additional sources
Causes: National Institute of Diabetes and Digestive and Kidney Diseases (2021). “Hypothyroidism (Underactive Thyroid)”
Autoimmune disorders: American Thyroid Association (n.d.). “Hypothyroidism (Underactive)”
Treatments: Endocrine Society (2021). “Combination thyroid hormone therapies treat hypothyroidism as well as levothyroxine”