Thyroid & Your Endocrine System

Your endocrine system

Your thyroid gland is part of the endocrine system, which controls many parts of you, such as:

  • Hypothalamus, which controls your water balance, sleep, temperature, appetite and blood pressure
  • Pineal body, which produces melatonin to regulate your sleep
  • Thyroid, which plays a crucial role in metabolism
  • Adrenal gland, which makes corticosteroid hormones, sex hormones and adrenaline
  • Pancreas, which produces insulin and glucagon that regulate blood sugar
  • Ovaries, which produce oestrogen and progesterone
  • Testes, which produce testosterone

This truly wonderful chemical messenger system regulates a whole range of bodily functions by releasing hormones, which use the bloodstream as their vehicle to transmit their messages.  Regulated functions include your metabolism, growth and development, reproduction, energy, response to injury, stress and mood.

The thyroid gland

Your thyroid is a butterfly-shaped gland situated at the front of your neck. It makes the hormones thyroxine (T4) and triiodothyronine (T3), which at the right levels, are necessary for the proper functioning of your body.  The amount of T4 and T3 produced is dictated by the amount of thyroid-stimulating hormone (TSH) produced by the pituitary gland.

Thyroid hormones impact your metabolism, heart, muscles, digestion, brain and bones and if their levels move away from a normal range, a host of symptoms can appear.  Disease and diet can both cause imbalances, which can also be triggered by exposure to excess iodine, exposure to lithium, inflammation, the growth of nodules and even pregnancy, childbirth and the menopause.  Thyroid problems are up to 10 times more common in women than in men.

Thyroxine (T4) contains four atoms of iodine and this is converted to tri-iodothyronine (T3), which contains three atoms of iodine.  Both T4 and T3 have a bound form and a free or active form.  The active form travels into relevant body tissues whereas the bound form attaches to proteins, which makes it inert.  You’ll see FT4 and FT3 on your blood test as the free form is the useful measure of your thyroid activity.

T3 has higher metabolic activity than T4 but a shorter lifespan.  A small number of people have trouble converting T4 into T3, which means that taking levothyroxine medication has limited effect and symptoms are still experienced.  Taking liothyronine medication can help and is usually only prescribed by consultant endocrinologists.


Hypothyroidism is a condition experienced when levels of thyroxine (T4) are lower than normal and is usually accompanied by higher levels of thyroid-stimulating hormone (TSH), which tells the thyroid gland how much T4 to make.  It causes symptoms such as weight gain, slower heart rate, fatigue, hair loss, memory impairment, dry skin and hair, hoarsening of the voice and intolerance to cold.  Hypothyroidism is treatable and should never be ignored.  Long-term suffering can have serious consequences such as peripheral nerve damage and cardiovascular disease.

Studies have shown that oestrogen has direct action in thyroid cells, which may explain why many women experience changes to their thyroid function after childbirth or the menopause.


Hyperthyroidism is a condition experienced when levels of thyroxine (T4) and triiodothyronine (T3) are higher than normal and is usually accompanied by lower levels of thyroid-stimulating hormone (TSH), which tells the thyroid gland how much T4 to make.  Typical symptoms for hyperthyroidism include weight loss, racing heart, irritability, nervousness, muscle weakness and tremors, infrequent menstrual periods, sleep problems, eye irritations and heat sensitivity.  It may also cause miscarriage and premature labour.  If left untreated, it can result in heart disease, eye complications and osteoporosis.

Autoimmune thyroid diseases

Hashimoto’s disease and Grave’s disease are both caused by the immune system attacking the thyroid gland.  In the case of Hashimoto’s disease, the resulting inflammation causes hypothyroidism and the gradual destruction of the thyroid function and in the case of Grave’s disease, it causes hyperthyroidism.

Thyroid antibodies are usually present and help to diagnose the autoimmune aspect of the hormone disorder.  These are called thyroid peroxidase antibodies, thyroglobulin antibodies and thyroid stimulating hormone receptor antibodies.  It is the presence of antibodies that causes such strong sensitisation in some thyroid patients, who may find themselves reacting to foods and medical ingredients that did not trouble them before.  Medical protocols exist to treat both of these autoimmune diseases but diet and lifestyle can play an important role, especially in the case of Hashimoto’s disease.  Low-dose naltrexone is also reported to help dampen the autoimmune response and reduce levels of antibodies.

Endocrine Disruptors

Endocrine disruptors (EDCs) are chemicals that can interfere with the proper functioning of the endocrine system.  They include substances such as BPA, phyto-oestrogens, phthalates, triclosan and dioxins.  EDCs operate across many different hormones and have been linked to a wide range of adverse health outcomes such as fertility issues, foetal abnormalities, endometriosis, early puberty, diabetes, obesity, respiratory issues, cardiovascular issues, learning disabilities and some cancers.

Many EDCs are banned from use, particularly in prenatal and baby products, where the most damage can be realised but many are still being used to make everyday products including plastics, personal care products and food packaging.

There’s some interesting research on EDCs, including this paper published in The Lancet in August 2020 and some useful information can be found here.

Natural Desiccated Thyroid

Natural desiccated thyroid (NDT) is dried and powdered thyroid gland from an animal, usually porcine.  As it is the whole gland, it contains more than just levothyroxine (T4) and liothyronine (T3); it also contains the hormone precursors T1 and T2, which are also produced by the thyroid gland. Medically, T1 and T2 are accepted as being inert, having little impact on bodily functions.

To make NDT into a medication, the manufacturer needs to ensure that the amount of T4 and T3 contained in each tablet is consistent and reliable.  NDT is measured in grains, where 1 grain usually contains around 38mcg of T4 and 9mcg of T3.   Patients who take natural desiccated thyroid products often report much better results than they get from taking synthetic T3 and T4, attributing this to the presence of T1 and T2.

Currently, Armour Thyroid and ERFA are the only available brands of NDT in the UK.  We hope to see WP Thyroid, Nature Throid and NP Thyroid back in the UK market later in 2021.  As a pharmacy, Roseway Labs also supplies many brands of licensed and unlicensed thyroid medication.  Please contact us for further information.