So what exactly is a Thyroid Gland and why people keep referring to thyroid being underactive and overactive? To put it in words, the thyroid is one of the largest endocrine glands in the body. The gland sits in in the neck and is approximately the same level as the cricoid cartilage. The function of thyroid gland is to produce hormones which control how quickly the body burns energy, makes new tissues and other hormones are affected by all this. .
The thyroid participates in these processes by producing thyroid hormones, principally thyroxine (T4) and triiodothyronine (T3). These hormones regulate the rate of metabolism and affect the growth and rate of function of many other systems in the body. Iodine and tyrosine are used to form both T3 and T4. The thyroid also produces the hormone calcitonin, which plays a role in calcium homeostasis.
Thyroid gland produces up to 5 different hormones and they are called
T1 - Mono-iodothyronine
T2 - Do-iodothyronine
T3 - Tri-iodothyronine
T4 - Tetra-iodothyronine
And - Calcitonin.
Above mentioned names are scientific and in real life we may hear different varities of those like T4 is called thyroxine which is branded as Eltroxin in the UK and Synthyroid in the US.
Learn more about Thyroid at the Thyroid Forums
Let's see what these hormones are supposed to do.
T4 (Thyroxine) - In very simple terms, Thyroxine is an inactive hormone in the blood which circulates in the blood and is converted to an active hormone T3 (triiodothyronine) when needed. Their half life is approximately 8 days meaning their strength becomes 50% after eight days what it was at the begining. Thyroid gland produces up to 80% of T4.
T3 (triiodothyronine) - It's the active hormone which is responsible for the metabolism of the body. It is produced by conversion of T4 into T3 by some chemical process of the body. It's half life is a few hours and it's almost 4 times as potent as T4. Thyroid gland produces up to 16% of T4.
T2 - There isnt too much written about it but just because no one knows what this hormone is supposed to do, doesnt mean it is no good. It's function is not quite understood but Dr. Peatfield says T2 alone is effective in increasing live metabolism and also that of heart, muscles tissue and brown adipose tissue.
T1 - Still a mystery hormone. Body produces almost 4% of T1 and T2 hormones.
Calcitonin - Not really much of a hormone but it plays some kind of important role in keeping calcium in bones.
In the meanwhile please visit and and join us at the Thyroid Forums and share your experience or problems you are facing.
The forum is run and managed by a group of volunteers. The whole idea of forum is to share the information, knowledge ane experience among patients in the similar boat. This forum is not a place to seek a medical advice or for prescription or drugs. Always seek a medical advice from your doctor before trying any medicine, drug or steroids. The forum should be taken as a guidance and learning source of the information.