Thyroid hair loss: what’s the connection?

It can feel unnerving if you start to notice thinning hair, and you may wonder what could be causing it. In some cases, hair loss can be caused by an underlying condition, like a thyroid disorder. Keep reading to learn all about thyroid-related hair loss and how to treat it. 

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The small, butterfly-shaped thyroid gland in our necks usually goes unnoticed until it causes problems. And whether the thyroid is producing too much or too little of the hormones that are important to so many different functions in our body, problems with thyroid function can affect hair growth, texture, pigmentation, and can even cause hair loss. 

The thyroid gland makes hormones called T3 and T4, which, among other things, regulate the body’s metabolism. 

Having too much of these hormones (a condition called hyperthyroidism) or too little of these hormones (hypothyroidism) can directly impact the hair growth cycle, potentially leading to hair loss (van Beek, 2008). 

Unlike the most common cause of hair loss, androgenic alopecia (better known as male or female pattern baldness), thyroid-related hair loss typically results in overall thinning of the hair (also known as diffuse hair loss), rather than a bald spot at the crown, a receding hairline, or isolated patches with no hair at all. 

Hair loss is more likely to develop when a thyroid condition has gone untreated, but it’s not the only symptom of thyroid disorders. 

If you have hypothyroidism (underactive thyroid), you may experience any of the following symptoms (Wilson, 2021):

• Sensitivity to cold or cold intolerance

• Fatigue

• Weight gain

• Dry skin

• Constipation

• Voice changes

Hyperthyroidism (overactive thyroid) may come with the following symptoms (De Leo, 2016):

• Heart palpitations (being aware of your heartbeat)

• Fatigue

• Tremor

• Anxiety

• Trouble sleeping or sleep disturbances

• Weight loss

• Heat intolerance

• Sweating

• Excessive thirst

Hair loss can develop for several reasons besides your thyroid health. Other possible causes of hair loss include:

• Genetics: A family history of male pattern baldness and female pattern baldness can increase your risk for hair loss.

• Alopecia areata: This is an autoimmune condition that causes hair loss.

• Hormonal changes: Pregnancy, endocrine disorders like polycystic ovarian syndrome (PCOS), or other hormonal changes can result in hair loss. 

• Nutrient deficiencies: Poor nutrition can lead to hair loss, including not getting enough fatty acids, iron, zinc, protein, or B-vitamins.

• Anemia: This is a condition where you don’t have enough red blood cells to deliver adequate oxygen to the cells.

• Scalp damage: Trauma to the scalp and hair follicles, like burns or scarring, can lead to hair loss and prevent that area from being able to regrow hair.

In most cases, thyroid-related hair loss may be treatable. Treatment depends on the thyroid condition you have. 

Hypothyroidism treatment

The standard treatment for an underactive thyroid is thyroid medication to replace these hormones. Synthetic thyroid hormones help replace the hormones your body isn’t producing, reversing the symptoms of hypothyroidism (Wilson, 2021). 

The most common treatment for hypothyroidism is levothyroxine (brand names include Synthroid, Levothroid, and Unithroid), a synthetic form of T4 (Shakir, 2021). Rarely and only under certain circumstances, a healthcare provider may recommend treatment with T3 instead, which is known as liothyronine (brand names include Cytomel and Triostat). While desiccated thyroid (brand names include Armour Thyroid and Westhroid), which is derived from animals, was once commonly used, it’s not prescribed as often today.

Treatment for overactive thyroid depends on the cause but may include (De Leo, 2016):

• Antithyroid drugs: These types of thyroid medications help reduce thyroid hormone levels in your body. Examples include methimazole and propylthiouracil.

• Ablation: This procedure uses radioactive iodine to destroy part or all of your thyroid gland to help reduce thyroid hormone levels.

• Surgery: A thyroidectomy, a procedure to remove part or all of the thyroid gland, may be recommended.

If you have thyroid-related hair loss, you’ll likely see hair regrowth after treating the underlying thyroid disease. In some cases, though, your hair loss could also be from one of the other causes of hair loss. 

Here are some common ways to treat hair loss from other causes:

• Minoxidil (Rogaine) is a topical solution applied directly to the scalp, which may help stimulate hair growth.

• Finasteride (Propecia) is an oral prescription medication to treat male pattern baldness.

• Nutrition supplements—If your hair loss is caused by a nutrient deficiency, like a lack of biotin, taking a supplement may resolve the hair loss. Speak with your healthcare provider about getting tested before starting a supplement regimen since only a small subset of people don’t get enough of their daily vitamins from the food they eat.

Losing your hair can be a stressful experience. Fortunately, if a thyroid problem causes your hair loss, the symptoms can likely be reversed. Your healthcare provider can help you create a treatment plan.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

May 05, 2022

Written by

Ashley Braun, RD, MPH

Fact checked by

Yael Cooperman, MD

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About the medical reviewer

Yael Cooperman, MD, Ro

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.