Correct Way

[KurdishMan]

"According to Thyroid Manager:

“Serum T4 (Free T4) concentrations peak two to four hours after an oral dose and remain above normal for approximately six hours in patients receiving daily replacement therapy.” For this reason, thyroid expert Richard Shames, MD has the following recommendation: “I absolutely recommend that patients have any morning blood tests evaluating the thyroid before taking any thyroid medication. I have always told my patients to do it this way.”"

[helvella Administrator Thyroid UK]

Completely agree. The peak of FT4 from taking levothyroxine is a very sharp peak which then tails off. It is effectively impossible to get a blood test which shows the peak. So the other alternative is, as Richard Shames says, the trough just before the next dose.

[MaisieGray]

There is no information in your profile, so are you asserting this is the case, or are you asking for confirmation that it is so? If you read through any day's posts here, you will say it repeatedly being recommended that blood draws are carried out as early as possible and certainly before 9.00 am, fasting - water only, and 24 hours after the previous dose of Levothyroxine (8 -12 hrs when taking T3 or NDT).