Thyroid and Hair Loss: Investigating the Link

Texture of hair can also change with thyroid dysfunction

Checking hair in mirror
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Some hair loss is a normal part of life. But when your hair loss becomes excessive and/or distressing, it's time to see your doctor for an evaluation as there are a number of potential culprits—one being your thyroid. 

Hair Life Cycle

To understand how hair loss manifests, it's important to first understand the anatomy or life cycle of each hair on your body. 

There are three phases of the hair life cycle:

At any given time, about 90 percent of the hair on your scalp is in the growth phase (called the anagen phase) meaning the hair is actively growing; the rate of growth and duration depends on the type of hair and where it's located.

The catagen phase, which lasts about three weeks and includes less than one percent of the hairs on your scalp, is the "in-between" or transition phase, upon which the hair has stopped actively growing.

The last phase (called the telogen phase) occurs over three months and is considered the resting phase, as the hair gets prepared to shed. Typically, about 50 and 150 telogen hairs are shed per day

The big picture here is that everyone loses hair—it's perfectly normal, and once your hair is shed, it's replaced by new hair.

Of course, when hair shedding becomes excessive or it's not growing back, health etiologies need to be addressed by your doctor—and often, your thyroid gland is top of the list.

Hair Loss and Your Thyroid

If you have thyroid disease and have noticed hair loss, it's normal to experience a range of emotions like anxiety, fear, or even anger. 

You may also be concerned about changes in your hair's texture, noticing that it has become dry or coarse (with hypothyroidism) or extra soft and fine (with hyperthyroidism).

While prolonged thyroid disease may cause diffuse hair loss, it's important to note that with treatment of your thyroid dysfunction, regrowth will typically occur (although it may take months and it may be incomplete).

Keep in mind, as well, that a loss of body hair from areas (other than your head) can also be seen. A unique and characteristic symptom of hypothyroidism is the loss of the hair on the outer edge of your eyebrows—a subtle clue that tips off some patients and doctors into checking a thyroid-stimulating hormone (TSH).

Hair Loss and Other Autoimmune Conditions

Besides the all over hair loss sometimes seen with thyroid disease, there are other medical conditions (linked to autoimmune thyroid disease) that may cause hair loss.

For example, in alopecia areata, a person does not experience generalized hair loss, but rather discrete, round areas of hair loss on the scalp or other areas of the body.

Lupus is another autoimmune condition (linked to autoimmune thyroid disease) that can cause hair loss. Although hair loss occurs through scarring, which means that the hair follicle is replaced by scar tissue, so hair loss is permanent.

Other Causes of Hair Loss 

Keep in mind that besides thyroid and other autoimmune diseases, there are many other causes of hair loss.

Some of the more common ones include:

  • Hormonal changes (for example, after a woman gives birth or menopause)
  • Nutritional deficiencies (for example, iron, zinc, and vitamin D)
  • Certain medications (for example, certain high blood pressure medications or blood thinners)
  • Genetic factors, meaning some types of hair loss are hereditary

Overcoming Hair Loss

If you are concerned about the amount of hair you are losing, here are some vital steps to take:

Get Evaluated by a Dermatologist

Even if you are in the midst of dealing with a thyroid problem, it's still a good idea to see a dermatologist. A good dermatologist can access whether there are additional issues contributing to your hair loss.

Consider Treatment

Depending on the cause of your hair loss, your doctor may recommend treatment, either an over-the-counter medication, prescription medication, or both.

Two examples of medications used to treat hair loss include:

  • Rogaine (Minoxidil) is available without a prescription. Rogaine is applied to the scalp (as a solution or foam). Keep in mind that it's common when people start Rogaine to experience increased hair shedding for the first month or two. This is believed to be due to the release of telogen hairs, as new hairs transition over to the growing (anagen) phase.
  • Propecia (Finasteride) is a prescription drug taken in pill form that is used mostly to treat male pattern baldness (called androgenetic alopecia). It cannot be used by women who are pregnant or considering pregnancy. 

A Word From Verywell

If you've been checked out by the dermatologist and determined to have thyroid-related hair loss, you will have to be patient. It's likely that for most of you, your hair loss will slow down and eventually stop once your thyroid hormone levels are optimized. This can take a few months, however.

In the meantime, hair thickening products, a change of style that doesn't pull on your hair, or wearing a weave or hair extensions may help you look your best.

View Article Sources
  • American Academy of Dermatology. (2018). Hair Loss. 
  • British Thyroid Foundation. (2018). Hair Loss and Thyroid Disorders. 
  • Cheung EJ, et al. Vitamin and Mineral Deficiencies in Patients With Telogen Effluvium: A Retrospective Cross-Sectional Study. J Drugs Dermatol. 2016 Oct 1;15(10):1235-1237.
  • Safer JD. Thyroid hormone action on skin. Dermatoendocrinol. 2011 Jul-Sep;3(3):211-15.
  • Shapiro J, Hordinsky M. Evaluation and diagnosis of hair loss. Callen J, ed. UpToDate. Walthmam, MA: UpToDate Inc.