Thyroid
The hormone that sets your metabolic pace.
TSH, free T4
5 min
Metabolism & blood
Sample reading
Ages 40–49
1.8
mIU/L
Low < 0.4
Normal 0.4–4.0
High > 4.0
Illustrative ranges. Your physician sets yours.
(01) How it’s done
On the day
Two markers from the morning draw, TSH and free T4, with thyroid antibodies if the first two are borderline.
Tell us if you take biotin supplements: they can distort the result, and we will ask you to pause them for two days.
(02) Why it matters
What it tells us
An underactive or overactive thyroid explains a lot of tiredness, weight change, low mood and poor sleep.
It is common, especially in women over forty, and it is simple to treat once it has been found.
(03) Same system
Metabolism & blood
Measured on the same day, read by the same physician.
