A friend of mine just gave me a link to a 1978 piece of research that confirms that TSH and FT3 peak in the night.
This knowledge is important and it is partly what supports my Circadian T3 Method (CT3M) optional protocol.
I have written about this in all my books, Recovering with T3, The CT3M Handbook, and my latest one The Thyroid Patient’s Manual.
This is only part of the data that supports the idea behind CT3M.
The other important reasons are that the pituitary has the highest concentration of T3 in the body and that it is the pituitary that begins to drive cortisol levels up in the latter part of the night.
Keeping FT3 levels up during that part of the night is important. This happens normally in healthy people, but often it does not in thyroid patients on daytime thyroid medication.
Any loss of thyroid tissue (through Hashimoto’s or thyroidectomy) also makes things worse as this loses a significant amount of T4 to T3 conversion capability. Any DIO1 and DIO2 gene defects might also be a big factor as they can impact conversion capability also.
Here is the research paper:
“Circadian and 30 Minutes Variations in Serum TSH and Thyroid Hormones in Normal Subjects”
Jorgan Weeke and Hans Jorgan G. Gundersen.
EJE Clinical and Translational Endocrinology.
(Updated in February 2019)