The thyroid, part of the endocrine system, is located in the lower neck just below the Adam’s apple and plays a vital role in the body. Thyroid hormones regulate energy levels and the reproduction of all cells, and every part of the body requires thyroid hormones for proper functioning, including the hair follicles, so imbalanced thyroid levels and hair loss often go hand in hand. Hyperthyroidism (overactive thyroid) can result in diffusely thinning hair everywhere on the head, while hypothyroidism (underactive thyroid) can cause hair loss on the head and elsewhere on the body. Thyroid disease may cause dry, itchy scalp and brittle hair, as well as weight gain or loss, fatigue or sleeplessness, and many other symptoms.
Can Thyroid Problems Cause Hair Loss?
In a 2008 study, the Journal of Clinical Endocrinology and Metabolism presented crucial evidence that thyroid hormones directly target human hair follicles. This research demonstrates that the thyroid hormones thyroxine (T4) and triiodothyronine (T3) modulate multiple aspects of hair biology, from the hair growth cycle to the pigmentation of hair.
Hair growth depends on the proper functioning of the thyroid gland, so abnormal levels of thyroid hormone produced by this gland can result in hair changes, along with other side effects. When there is too much thyroid hormone (hyperthyroidism) you may see thinning hair all over the scalp. Whereas, women with hypothyroidism may see more extreme hair loss, not just on the scalp but elsewhere on the body.
Thyroid Medications and Hair Loss
Ironically, not only do imbalances of thyroid hormones cause thinning hair, but thyroid medications themselves can cause hair loss. However, users generally report that hair loss is more common within the first month of starting the medication, and is generally temporary. As thyroid hormone levels stabilize, hair growth generally returns to normal.
Hypothyroidism and Hair Loss
As we’ve said, thyroid levels and hair loss are inextricably linked. Hair loss due to thyroid is linked to hypothyroidism, low levels of thyroid hormones, which reduces the ability of the body to regenerate cells. Women are five times more likely to be diagnosed with hypothyroidism than men and the odds increase with age. According to the American Association of Clinical Endocrinologists, the autoimmune disease Hashimoto’s thyroiditis is responsible for up to 80% of hypothyroid cases in the US and in the developed world. In the developing world, hypothyroidism often is caused by iodine deficiency. Endocrinologists advise that individuals with one autoimmune disease are more at risk for other autoimmune diseases. For instance, the hair loss condition alopecia areata is an autoimmune disorder in which the immune system attacks the hair follicles. Thus, women who have hypothyroidism due to Hashimoto’s thyroiditis may be more susceptible to developing alopecia areata.
Low Ferritin, Nutrient Deficiency and Hair Loss
Nutrient deficiencies are also a common issue for people with hypothyroidism. Not only are nutrients essential for thyroid function, but they play an important role in healthy hair growth. In particular, low ferritin (the stored form of iron on the body) is one of the most common causes of hair loss in women. Low ferritin is also a common problem for people with hypothyroidism. If you are experiencing excessive thinning hair or hair loss, ask your doctor to test not only your iron but your ferritin levels. Dr. Philip Kingsley, a world-renowned trichologist (hair and scalp expert) explains the link between ferritin levels and hair loss: “Correct ferritin levels maximize your hair’s anagen, or growing, phase of the hair growth cycle and encourage your hairs to grow to their full length. When you aren’t getting enough iron through your diet, your body takes ferritin stored in non-essential tissue, like your hair follicles, and gives it to essential tissue, such as your heart. Because your hair bulb is where all your hair cells are produced, this leeching of ferritin can cause your hair to shed before it reaches its maximum length.” Supplement a healthy balanced diet with a clinically tested hair growth supplement that contains iron, B vitamins, marine extracts, zinc and vitamin C.
Thyroid with Itchy Scalp and Brittle Hair
If in addition to thinning hair or hair loss, your thyroid hormone imbalance is causing itchy, dry scalp, add a topical hair serum for women with menthol to your hair care routine. If your thyroid condition is causing dry, brittle hair, use a gentle shampoo and moisturizing conditioner that is SLS-free and SLES-free, which will help minimize irritation on dry, sensitive scalp.