The Thyroid gland manages your weight, mood, energy, temperature and your memory. It also works closely with the adrenal glands and the blood sugar system to regulate your energy.

Overall, the thyroid gland is responsible for the speed of your cellular function or metabolic rate. This includes the speed of your reflexes, heart, brain and so on, by affecting all the cells, tissues, organs and systems in your body. The thyroid gland is essential for life, growth and development. It works with all your hormones to coordinate them.

Hormones excreted by the thyroid include T4, T3, T2, T1 and calcitonin. The thyroid manufactures 80% of all your T4, 20% of all your T3 (quantities and function of T1 and T2 are largely unknown). T3 is five to seven times stronger than T4.

How does Thyroid function work?

The thyroid is stimulated by a hormonal messenger from the brain called Thyroid Stimulating Hormone (TSH) to secrete thyroid hormone T4. When the thyroid is functioning properly it produces thyroid hormones T3 (Tri-iodothyronine), and T4 (Tetra-iodothyronine) from tyrosine (a protein) and iodine. The hormone calcitonin is also produced by the thyroid and is involved in the regulation of calcium in the body and therefore affects neurotransmitter, muscle and bone health.

thyroid hormones. Human endocrine system. Human anatomy

The thyroid hormones are chemical messengers that deliver instructions to various target tissues and organs via the bloodstream. The cells within the target organs then use the thyroid hormones and respond by speeding up or slowing down their activities in all parts of the body.

The 3 Key Facts

1. Hyperthyroidism – your thyroid produces excess T3 or T4, which speeds up the rate you burn calories.

2. Hypothyroidism – your thyroid is under producing T3 or T4, which slows the rate your body burns fuel. You can be born with this or it can develop later in life.

3. It is important to note that in older people hypothyroidism is also mixed up with the natural signs of ageing.


The Thyroid Gland and its functions can be likened to driving in a car in the wrong gear. If you’re in first gear and driving at 50kms an hour, you’re revving too high or overworking, this can be likened to Hyperthyroidism. However, driving in fourth gear at 15kms an hour, causes you to slow down, and eventually stall the car, this can be likened to Hypothyroidism. Neither is ideal so you need it to be balanced and functioning properly!