T3 or T4 -active

[thyroidnodules]

I though i understood all the T's and their purpose. However, i have been looking at horizon blood tests and their explanations of the T's and i am a little confused again. This is what it says :-

"Free T4 (free thyroxine) is the active form of thyroxine, released from the thyroid gland in the neck. Its role is to control metabolism - release of energy from all cells of the body. A lack of thyroxine leads to, for example, tiredness and weight gain, whereas an excess will lead to weight loss, rapid heart rate and anxiety. It is generally believed that this level (FT4) is the most reliable indicator of thyroid status - ie whether the gland is over-active (hyperthyroidism) or underactive (hypothyroidism).

Free T3 (Free Triiodothyronine) - This is one of two hormones produced by the thyroid gland. This measures the level of T3 that is 'free' and is able to regulate metabolism".

I thought T3 was the active hormone. oh well, back to the drawing board.

[cjrsquared]

T3 is the active hormone with t4 converted into t3 in peripheral tissues. The explanation you have posted is simplified and incorrect, such as that given to children or those deemed not very bright. It is a dumbed down response from the testing company.

[thyroidnodules in reply to cjrsquared]

I see, its bad practice though isnt it. This was a post on this forum from blue horizon as well. good to know though that im not as stupid as i thought lol

[Hidden]

Whoever wrote that needs re-educating!