Can thyroid problems cause hair loss?

Can Thyroid Problems Cause Hair Loss?

Medically reviewed on January 7, 2022. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Hair loss is one of the most common conditions amongst humans. By the age of 35, roughly two-thirds of men in the United States will experience some form of hair loss, and by age 50, 85 percent of men experience significant hair thinning. Women are not excluded from this condition either. Some estimates suggest that up to 32 percent of women over the age of 20 will experience some form of excessive hair loss [1].

Outside of certain autoimmune diseases, the exact cause of hair loss is not well-understood. Science generally agrees that it is a combination of genetics, hormones, personal health, and environmental factors. Considering how important the thyroid is, many wonder if their thinning hair and/or hair loss is a symptom of thyroid problems. Learn more about thyroid issues and thyroid-related hair loss below.


The Thyroid Gland

Your thyroid gland is located at the front of your neck, wrapped around your trachea. While relatively small in size, the thyroid function is mighty. The thyroid function is to produce important hormones that regulate your metabolism, which is the process by which your body converts food into energy [2]. Along with metabolism, thyroid hormones play roles in:

  • Regulating the heart and muscles
  • Supporting digestive function
  • Supporting brain development
  • Maintaining bone health [2]

An inactive or underactive thyroid can cause fluctuations and imbalances in thyroid hormones, which can have a severe effect on your hair growth and overall health [2].

Check if your thyroid hormones are balanced from the convenience of home with the Everlywell at-home Thyroid Test.

The Hair Cycle

It’s normal to lose some of your hair on a consistent basis. The average person loses 50 to 100 strands every day, but thousands of other hairs are growing to replace those. During the anagen phase, hair follicles are actively growing. The typical rate is about 1 cm every 28 days [3].

Once the hairs have reached their maximum growth potential, they reach the telogen phase. This is known as the resting phase and lasts for about 100 days, after which the hairs naturally shed on their own. The hair follicle then begins the hair regrowth cycle all over again [3].

Hair loss is characterized by a shortened growth phase and an extended resting phase. As the hair cycles, you essentially shed more hairs faster than your scalp can grow them back [3].

Thyroid Problems and Hair Loss

While the thyroid may seem entirely separate from the hairs on your head, the two are more connected than you may realize. Remember, the thyroid is involved with metabolism throughout the body, and this process includes supporting your hair follicles [3].

Thyroid hormones are directly involved with functions in the hair follicle. Too much or too little thyroid hormones can contribute to an extended resting phase, resulting in more hair shedding. This thyroid problem is known as telogen effluvium, which is also often triggered by extreme stress or traumatic moments [3].

The good news about telogen effluvium is that it is generally temporary, and it can be reversed once you address the underlying thyroid condition.

It’s important to understand that hair loss can have numerous causes and that it’s normal for most people to have thinning hair as they get older. However, if you’ve tried hair loss or regrowth treatments to no avail, it may be worth getting your thyroid levels tested with the Everlywell at-home thyroid test. This may explain underlying health issues you may have been experiencing along with hair loss.

How to Understand Thyroid Levels

Can Stress Cause Thyroid Problems?

Can Thyroid Problems Cause Headaches?


1. Hair Loss. ScienceDirect. URL. Accessed January 7, 2022.

2. Thyroid gland. You and Your Hormones. URL. Accessed January 7, 2022.

3. Tell Me More: How to Know if Your Thyroid's Causing Your Hair Loss. Keeps. URL. Accessed January 7, 2022.

Everlywell makes lab testing easy and convenient with at-home collection and digital results in days. Learn More