T4 thyroxine
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Guidance on what time of day it is best to take T4 and/or T3?
How would you address normal TSH but low T4?
Once TSH signals to your thyroid to ramp up production of its hormones, it produces the four different types of thyroid hormone – T1, T2, T3, and T4. The thyroid takes iodine, hydrogen peroxide and puts it together with tyrosine and it makes T4. 97% of what comes out of the thyroid gland is inactive T4. The primary output of your thyroid is T4, which is a storage form of the hormone. It is circulated throughout the bloodstream and stored in tissues so that it’s available when needed. Measure Free T4 (FT4) since it is unbound and able to act in the body.
- If FT4 is high – it can indicate an overactive thyroid or hyperthyroidism
- If FT4 is low – it can indicate an underactive thyroid or hypothyroidism