Ear, Nose and Throat

Thyroid Problems: Fluctuating Weight, Hair Loss and More

Originally published January 31, 2017

Last updated August 16, 2022

Reading Time: 3 minutes

A small, butterfly-shaped gland tucked right underneath your Adam’s apple can have a huge impact on your health.

Your thyroid produces hormones that control everything from digestion and heart function to muscle control and metabolism. When the thyroid produces too many or too few hormones, you can experience a wide range of health issues.

If you suspect you may have thyroid trouble – especially if someone in your family has been diagnosed – your primary care physician can use a simple blood test to assess your thyroid function. Depending on your diagnosis, you have many treatment options. The experts at the USC Caruso Department of Otolaryngology-Head and Neck Surgery are continually researching new treatments and therapies for thyroid conditions.

There are many types of thyroid conditions, but the two most common are hypothyroidism and hyperthyroidism. Women are more likely to develop thyroid trouble, particularly after pregnancy and menopause.


Hypothyroidism, or underactive thyroid, can slow your metabolism and cause many problems, including:

Hair loss – When your metabolism slows, your body may invest more energy trying to keep vital functions going rather than maintaining healthy hair. You may experience hair loss, or your hair may become brittle or coarse. Frequently feeling cold – Low metabolism can make you feel sluggish and you may struggle to stay warm.

Weight gain – If you haven’t been eating more or exercising less, yet find yourself gaining weight, an underactive thyroid may be suppressing your metabolism.

Muscle or joint pain – When the thyroid isn’t working properly, you may experience swelling and inflammation in the joints and muscles, which can cause aches and pains, plus plantar fasciitis in the feet or carpal tunnel in the wrists.

Constant fatigue or depression – A malfunctioning thyroid can decrease the amount of serotonin produced by your brain, potentially causing fatigue, sadness or depression.


When the thyroid is overactive and produces too many hormones, your metabolism will speed up, causing different symptoms:

Constant hunger and/or weight loss – Hyperthyroidism can make you lose weight and be constantly hungry, even if you’re eating as you always have. You may also have more frequent diarrhea or bowel movements.

Rapid or irregular heartbeat – Your heart may feel like it’s pounding, and you may have trembling in your hands and fingers. You may also sweat more.

Anxiety or irritability – A fast metabolism may make you feel nervous, anxious or irritable.

Fewer or lighter periods – Women with hyperthyroidism may have fewer or lighter menstrual periods, potentially affecting ovulation and leading to infertility. Thyroid trouble may also lead to low sex drive or miscarriage.

Is your thyroid working properly?

A simple blood test through your primary care physician can check your thyroid function, and many thyroid conditions can be managed with medication. If you think you may have thyroid trouble, request an appointment with a Keck Medicine of USC physician through the online form, or by calling (800) USC-CARE.

The American Thyroid Association Office on Women’s Health, U.S. Department of Health and Human Services Thyroid Foundation of Canada