What is the thyroid?

The Thyroid is a butterfly shaped gland located in the neck just behind the larynx (voice box). The thyroid is divided into 2 main regions, the right and left lobes which are connected by a narrow passage called the isthmus. The thyroid consists of tiny sacs called follicular cells which secrete thyroid hormones into the blood when stimulated by TSH (thyroid stimulating hormone) which is produced by the pituitary gland. The thyroid gland is also able to store large quantities of its hormones.

Hormones produced by the thyroid include:

  • Thyroxine (T4) – T4 is stored by the thyroid and some other tissues of the body which is later converted into T3.
  • Triiodothyronine (T3) – T3 is the active thyroid hormone which is released upon stimulation by TSH.
  • Calcitonin – counteracts the effects of parathyroid hormone (PTH) of the parathyroid glands (smaller glands found behind the thyroid). Calcitonin reduces blood calcium and phosphate levels when they are too high.

What does the thyroid do?

Nearly every cell in the body has receptors for thyroid hormones. The main function of the thyroid is to increase the basal metabolic rate of cells. In simple terms this means a cells capacity to consume oxygen increases, producing energy in the form of ATP (Adenosine triphosphate), which increases the rate of a cells various processes.  Protein, carbohydrate, and lipid metabolism increases, T3 is also involved in cellular growth, neural development, thermoregulation, and increases the body’s sensitivity to catecholamines, such as adrenaline which will increase heart rate. In a nutshell, if your body was a factory, your thyroid would be in charge of production! Speeding things up when demand is high and slowing things down again when needed…… so, it is a pretty important gland!

What thyroid issues can cause hair loss?

There are numerous conditions which can affect the thyroid gland, and some are incredibly rare. This post will focus on the most common issues affecting the thyroid.

Hypothyroidism (underactive thyroid):

When the thyroid doesn’t produce enough thyroid hormone (T3/T4) it is considered underactive, a condition known as hypothyroidism. As a result, overall metabolic rate reduces, causing symptoms such as fatigue, weight gain, muscle weakness/pain, depression, and hair loss. Hypothyroidism can affect men, women, and children, but is more commonly seen in women between the ages of 40 and 50.

How can hypothyroidism affect my hair?

Hair cells are busy cells! They are the second fastest dividing cells of the body and require a huge amount of energy to do their job. A reduced metabolism, doubled with the fact that growing hair is not a priority to your body and its survival…… and it is easy to see how an underactive thyroid can cause hair loss! An underactive thyroid mostly causes a type of hair loss called telogen effluvium, were the growing (anagen) phase of numerous scalp hairs is arrested and moved into their resting (telogen) phases prematurely. Affected hairs will then exit the scalp roughly 3 months later, causing an overall increase in shedding during this period.

Not everyone with an underactive thyroid will experience hair loss, but for those that do hair loss is typically diffuse with some increase in shedding. The scalp is most often affected, and sometimes the eyebrows (particularly outer third of the eyebrows) can become thinner. Hair can appear weak and brittle (especially towards the front), and a dry itchy scalp may also be a symptom in some people. Hypothyroidism can also be a trigger for alopecia areata (patchy hair loss).

Can hair loss caused by hypothyroidism be treated?

Yes it can! The treatment for hypothyroidism is usually by replacement of the thyroid hormone thyroxine with a medication called levothyroxine. Hypothyroidism is a lifelong disease, which requires continuous medication, but if the condition is managed well the symptoms should start to improve in time, including the hair loss! Topical medications, as well as other non-medical based therapies can be used to promote hair growth in some cases. Maintaining a well-balanced diet, and care of self will also help during the recovery process. Specific blood tests should also be ordered to rule out the possibility of other factors that may be affecting the hair.

What can cause hypothyroidism?

  • Hashimoto’s disease (an autoimmune condition)– This is a very common cause of hypothyroidism, where antibodies of the immune system attack the thyroid blocking the action of TSH on thyroid cells, preventing the production of thyroid hormones.
  • Malfunction of the hypothalamus or pituitary gland
  • Genetic abnormality
  • Treatment for hyperthyroidism – Some people may initially over-respond to hyperthyroid treatment, which can send the thyroid into an underactive state, until a suitable level of medication is found.
  • Radiation therapy
  • Thyroid surgery
  • Some medications – such as lithium containing medications.

Hyperthyroidism (over active thyroid):

Hyperthyroidism is the term used to describe an overactive thyroid (over production of thyroid hormones). Symptoms can include breathlessness, fatigue, heart palpitations, irregular menstrual periods, hyperactivity, weight loss, and exophthalmos (bulging eyes). Hyperthyroidism can occur in either sex and at any age, however it tends to be more common in women and younger age groups.

How can Hyperthyroidism affect my hair?

Hair loss is more commonly seen with underactive thyroid conditions; however, any type of thyroid issue can potentially cause some hair loss. Hair loss experienced is usually a diffuse thinning/shedding throughout the scalp (telogen effluvium), which for many seems to start quite suddenly. The cause of hair loss with an overactive thyroid is often the medication used to treat the condition (usually Carbimazole).

Can hair loss caused by hyperthyroidism be treated?

In the case of medication causing the hair loss, this can sometimes resolve on its own, or an alternative medication can be discussed with your GP. As with an underactive thyroid, the hair loss is a symptom so in most cases hair loss will improve once the condition is successfully managed. Some causes of hyperthyroidism may require a surgical procedure which can also trigger acute increase of hair shedding, which is a temporary issue. Blood tests to rule out other common causes of hair loss should also be done, as the symptoms of thyroid disorders often mimic other conditions.

What can cause hyperthyroidism?

  • Grave’s disease (Autoimmune condition) – by far the most common cause! Grave’s disease occurs when the immune system mistakenly attacks the thyroid causing the over production of thyroid hormones. This condition quite often precedes an underactive thyroid state.
  • Benign thyroid nodules
  • Iodine containing medicine
  • Pituitary adenoma – a benign tumour of the pituitary, causing an increase in TSH (thyroid stimulating hormone)
  • Thyroid tumours (rare)

How can I look after my thyroid?

  • If you have a family history of autoimmune related thyroid disease, its important to let your GP know and be on the look out for any associated symptoms. As with most conditions, the earlier these issues are discovered, the easier they generally are to treat.
  • If you are already being treated for a thyroid disorder, make sure to take any prescribed medication as directed, and follow the advice given to you by your GP and/or endocrinologist.
  • Maintain a healthy weight. Eat a healthy balanced diet (no crash/restrictive diets). Make sure to include lots of vegetables and fruit, omega 3, and lean protein.
  • Stop smoking.
  • Ditch the biotin supplements! Biotin can interfere with thyroid blood tests, leading to inaccurate blood results. Although biotin is an essential vitamin for hair growth, deficiency in the western world is incredibly rare. Furthermore, there is no scientific evidence to support biotin supplements help with hair loss.
  • Be cautious of iodine supplements! Many people choose to take iodine as it’s needed to make thyroid hormones, but overdoing it could be harmful to your thyroid. You should be able to get adequate iodine from a healthy balanced diet. If you are vegetarian/vegan, supplementing may be of benefit, but please check with your GP first.
  • Increase intake of antioxidants, such as omega 3, fruit and veg, selenium, and zinc. Especially useful if you are suffering with Hashimotos/Graves disease (see below)
  • Omega 3 (oily fish, olive oil, nuts and seeds, Brussel sprouts)
  • Foods high in zinc/selenium (seafood, brazil nuts, flax seed, lean meat, dark chocolate)
  • Get outside for at least 20 mins a day, this will help to maintain good vitamin D levels which is essential for immune health. Really important for anyone with auto immune disorders. Its worth supplementing with vitamin D during the winter months (October – March).