Hair loss can occur when the thyroid gland is not working properly. It can be a sign of either hypothyroidism or hyperthyroidism.

The thyroid gland is a butterfly-shaped gland situated in the lower front part of the neck.

The thyroid gland makes thyroid hormones, which the body uses for energy, to stay warm, and to keep the organs and muscles working properly.

The most common thyroid-related problems result from an abnormal production of thyroid hormones. Hypothyroidism, or an underactive thyroid, involves insufficient amounts of thyroid hormone. Hyperthyroidism, or an overactive thyroid, occurs when the thyroid gland produces too much hormone.

Having an overactive or underactive thyroid gland may cause hair loss in some people.

Typically, autoimmune conditions are the most common causes of abnormal thyroid hormone levels. For example, Hashimoto’s thyroiditis often causes hypothyroidism, while Graves’ disease is commonly responsible for hyperthyroidism.

In this article, we examine the link between thyroid function and hair loss. We also look at possible treatment options and home remedies for thyroid-related hair loss.

A man experiencing hair loss because of a problem with his ThyroidShare on Pinterest
Hair loss is a possible symptom of hypothyroidism or hyperthyroidism.

The thyroid hormone plays an essential role in the development and maintenance of the hair follicles. Follicles are the small pockets under the skin from which hairs grow. Severe or prolonged hypothyroidism or hyperthyroidism may result in hair loss.

Hair roots usually rotate the work of making hair. For example, hair roots on the head typically grow hair for a few years and then take a break.

When the body has too much or not enough thyroid hormone, it can “shock the system” into a state of telogen effluvium.

Telogen effluvium is a scalp disorder where the hair roots enter the resting stage of the hair cycle too early. As many as 70% of scalp hairs can fall out within about 2 months during a state of telogen effluvium.

When someone has one type of autoimmune condition, they are more likely than other people to develop another. For example, people with Hashimoto’s thyroiditis may also develop autoimmune alopecia, which results in diffuse hair loss. Alopecia areata causes hair loss in a more localized pattern.

Hair loss is also a possible side effect of some antithyroid drugs, including methimazole and propylthiouracil (PTU). Doctors prescribe antithyroid drugs to treat an overactive thyroid.

Some hair loss is perfectly normal. People can expect to lose 50–100 hairs from their bodies every day as part of the normal hair growth cycle.

People with telogen effluvium often find that their hair comes out in handfuls. It is usually most noticeable on the scalp but can affect hair on any part of the body.

Someone with autoimmune alopecia may notice that they lose discrete, often circular, patches of hair.

It is unusual for hair loss to be the only symptom of an overactive or underactive thyroid.

Other common symptoms of hypothyroidism include:

  • feeling cold
  • unexplained weight gain
  • tiredness
  • drier-than-usual skin
  • forgetfulness
  • low or depressed mood
  • constipation

Other common symptoms of hyperthyroidism include:

  • nervousness
  • irritability
  • increased sweating
  • fast heartbeat
  • hand tremors
  • anxiety
  • difficulty sleeping
  • thinning of the skin
  • fine or brittle hair
  • muscle weakness
  • more frequent bowel movements
  • unexplained weight loss
  • tiredness
  • swelling around the eyes, with occasional protruding of the eye, and “stare” (in the case of Graves disease)

People who have underactive or overactive thyroid glands may also experience abnormalities in their menstrual patterns.

It is worth noting, that hair loss, as well as hyper-and hypothyroid symptoms, are nonspecific and might be due to other conditions as well. Therefore, a person must visit their doctor to have their thyroid levels checked before a doctor can make a diagnosis.

Treating thyroid-related hair loss requires treating the thyroid problem.

A doctor will usually prescribe a synthetic hormone called levothyroxine sodium (Levothroid, Levoxyl, Synthroid, or Unithroid) to treat an underactive thyroid

Treatment for an overactive thyroid varies from person to person. Some of the most common methods include:

  • Antithyroid drugs. Antithyroid medications, such as methimazole (Tapazole) and PTU, work by blocking the gland’s ability to make the thyroid hormone.
  • Radioactive iodine. Doctors sometimes recommend internal radiation therapy. This damages the cells in the thyroid gland and reduces the amount of hormone that the gland produces. The treatment aims to induce hypothyroidism, which a person can then manage with thyroid hormone replacement.
  • Surgery. Surgery involves the removal of some or all of the thyroid gland, which may lead to hypothyroidism.

People living with thyroid disorders that can lead to hair loss often require medication to manage their condition.

In general, eating a balanced diet can help to promote growth and improve the condition of hair. A healthful and balanced diet is one that contains protein, fruits, vegetables, grains, and a moderate amount of fat.

Foods that can increase the chances of having healthy hair include:

Fish: Oily fish contains omega-3 fatty acids that can help prevent a dry scalp.

Dark green vegetables: Vegetables such as spinach have high levels of vitamins A and C. These vitamins can improve the condition of hair.

Protein-rich foods: Eating foods rich in protein can help prevent weak and brittle hair. Dairy foods, legumes, nuts, and lean meats all contain high levels of protein.

Biotin-rich foods: Biotin is a vitamin that is important for hair growth. Biotin deficiency can lead to brittle hair or hair loss. Sources of biotin include whole grains, liver, egg yolk, soy flour, and yeast. Biotin is also available in many over-the-counter (OTC) hair vitamins. However, biotin can affect the results of thyroid blood tests, so anyone having a blood test should stop using or consuming products containing biotin for a few days beforehand.

Calcium-rich foods: Calcium is key to hair growth. Good sources of calcium include dairy products, such as milk and cheese.

An overactive or underactive thyroid is not the only cause of hair loss. Other reasons for hair loss may include:

  • pregnancy or childbirth
  • getting older
  • stress
  • illnesses
  • surgery
  • nutritional problems
  • iron deficiency
  • anemia
  • an excessive amount of male hormones
  • genetic predisposition
  • dermatologic scalp problems

If a person has symptoms of an overactive or underactive thyroid, they should speak with their doctor.

A doctor may review a person’s medical history and conduct a physical exam.

A doctor will also order blood tests that measure levels of thyroid-stimulating hormone (TSH) and the thyroid hormone thyroxine. Whether these hormone levels are high or low determines whether a person has an overactive or underactive thyroid.

Without medical attention, the problem and its symptoms will usually get worse.

Thyroid-related hair loss will usually improve once a doctor treats the underlying health condition.

According to the American Osteopathic College of Dermatology, hair shedding decreases 6 to 8 months after treatment.