Does hypothyroidism cause hair loss in women?

As many as two thirds of women can experience hair loss during their life time. According to American Academy of Dermatology, about 40% of women have noticeable hair loss when they reach the age of forty. For many, thinning and loss of hair is not only a cosmetic issue that makes them feel unattractive and uncomfortable but is an emotionally stressful situation that can even cause depression.

Despite of widespread concerns among women about their hair problems, most doctors don’t take it seriously and often blame aging as a main cause. The truth is that 95% of women with hair loss have some sort of thyroid involvement which contributes to their hair issues.

Thyroid hair loss

Hypothyroidism causes hair loss because the slowing down of the metabolism affects scalp follicles and results in diminished hair strength and quality. At hypothyroidism, hair problems can start with thinning and changes in its structure when it becomes dry, brittle and coarse. In the advanced stages, hair falls out evenly or in large chunks that often can be noticed during brushing or hair wash.

Hair loss mostly occurs when hypothyroidism is undiagnosed or undertreated. Official normal TSH testing range is too broad and differs from lab to lab making the diagnosis of underlying thyroid condition more difficult. If a woman has subclinical hypothyroidism or her TSH is not in the optimal range which is around 1.0 it can result in low thyroid symptoms including loss of hair.

Low levels of metabolically active T3 hormone and thyroid hormone resistance can also cause hair loss in women. Adding a T3 medication can improve hypothyroid symptoms, quality of hair and stop hair loss. If hypothyroidism is properly treated the hair starts to regrow.

In addition, some drugs including thyroid replacement medication Synthroid states excessive hair loss as one of many possible side effects. Surprisingly, many patients and doctors are unaware of this fact.

Iron deficiency and thyroid hormone disorders are the two common conditions often associated with diffuse hair loss and most of the time there are no apparent clinical signs indicating it. Furthermore, sub-optimal and low iron levels are often in women with hypothyroidism and Hashimoto’s disease in particular.

There are 3 most common types of diffuse hair loss in women:

  1. Telogen effluvium which is sudden, rapid shedding of hair lasting for about 3 to 6 months.
  2. Chronic telogen effluvium occurs when the hair loss persists beyond six months and the condition becomes chronic.
  3. Female pattern hair loss which is a gradual diffuse hair loss with thinning of central scalp and widening of central parting line.

Besides iron deficiency anemia, hypo- and hyperthyroidism, malnutrition, vitamin and zinc deficiency has been most widely accepted as major causes of chronic diffuse hair loss.

Alopecia areata is a non-scarring hair loss disorder with the highest incidence in patients under 30 years of age and a lifetime incidence risk of 2% among the general population. It is an autoimmune disorder that is characterized by patchy hair loss or bald spots on the scalp.

Besides hair loss on the scalp some patients have nails, eyebrows, eyelashes and body hair affected. Alopecia areata frequently occurs in association with Hashimoto’s thyroiditis, clinical and subclinical hypothyroidism, anemias and skin disorders of autoimmune etiology.

Hormonal changes due to ovarian cysts, high androgen levels, birth control pills, pregnancy and menopause cause hormonal shifts that can result in hair loss. Fluctuations in estrogen, progesterone and testosterone levels affect hair growth and any event that causes an imbalance of those hormones can trigger the fallout.

Using of synthetic hormones in contraceptives disrupts natural hormonal pathways. Loss of scalp hair is one of known side effects when a synthetic progestogen is combined with estrogen in the birth control pills. Furthermore, discontinuing of oral contraceptives can also result in hair loss in some women due to adjusting of hormones to their natural levels that can take up to 5 years.

Other women go off birth control pills to get pregnant and are able to restore their hormonal levels quickly. They often associate their hair loss issues with pregnancy, when in fact it has happened due to the discontinuation of birth control pills.

Up to 50% of women notice that they are shedding more hair than usual during the first 6 months after giving birth. Postpartum hair loss is a temporary event that is caused by abrupt drop in hormones that are returning to the normal pre-pregnancy levels.

Low progesterone in perimenopause and menopause as well as in young women with hormonal imbalances can trigger hair loss. In un-ovulating women progesterone levels fall causing the body to increase the production of the adrenal cortical steroid called androstenedione which is an alternative precursor of androgen testosterone. This hormone promotes some androgenic male like properties including male pattern hair loss. By restoring the body’s progesterone levels androstenedione gradually decreases and re-growth of hair occurs usually within 6 to 12 months. Most women report improvement of hair thickness and texture while using the bio-identical progesterone.

Androgenic alopecia is caused by high levels of testosterone metabolite di-hydrotestosterone (DHT). This condition is very common in women with PCOS. About one third of women with PCOS have elevated thyroid antibodies. Furthermore, high levels of TSH and damage of the thyroid tissue were found in more than 40% of the PCOS women with Hashimoto’s disease. Both thyroid issues and high DHT in this group of patients can cause substantial hair loss.

Increased insulin production due to a diet high in carbohydrates stimulates the hormone production by the ovaries causing high androgen levels. At PCOS, conversion of testosterone to estrogen in the ovaries is impaired and results in an excess of testosterone. Male pattern baldness and hair loss are common symptoms of PCOS due to over conversion of testosterone to its metabolite DHT.

Reversing PCOS by following a sugar reducing diet, using supplements and regular exercise to address the insulin resistance is critical for restoring hormonal balance and thyroid support in women with PCOS. Herbal treatments for hair loss such as evening primrose oil are one of natural treatments well known for its inhibiting properties of the production of DHT in hair follicles and can help to prevent hair falls and stimulate re-grow.

Thinning and loss of hair can be an indicator for coexistence of other health issues. Besides hair problems, majority of women have other accompanying symptoms such as fatigue and weight gain. Establishing and correcting the underlying disease such as hypothyroidism and PCOS not only improves the general well-being but also stops hair loss in most cases.

P.S. Do you like what you read and want to see more?  Do you want to know about holistic approach to your health? Subscribe to the Outsmart Disease thyroid blog updates and get your FREE e-mail course Nutritional guide for Hashimoto’s disease


 The truth about women’s hair loss by Spencer David Kobren, McGraw-Hill; 1st edition, 2001

Women’s hair loss: The hidden epidemic by Dr. Michael Lorin Reed, Lock & Mane, LLC; 1st edition, 2009

Thyroid guide to hair loss: Conventional and holistic help for people suffering thyroid-related hair loss by M.J.Shomon, CreateSpace, 2008

Diffuse hair loss in an adult female: approach to diagnosis and management. Indian J Dermatol Venereol Leprol. 2009 Jan-Feb; 75(1):20-7; quiz 27-8.

Alopecia areata and autoimmunity: a clinical study. Indian J Dermatol. 2008; 53(2):70-4.

Clinical profile and impact on quality of life: Seven years experience with patients of alopecia areata. Indian J Dermatol Venereol Leprol. 2011 Jul-Aug; 77(4):489-93.

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