Dr. Tania S. Smith of Thyroid Patients Canada has written a technically excellent article entitled Thyroid T3 Secretion Compensates for T4-T3 Conversion. I will attach two links at the end of this introduction.
Dr. Smith’s article is an analysis of the classic 1990 thyroid science article by Alessandro Pilo and team, and it supplements it with insights from more recent thyroid science.
The article debunks the commonly held view about the 20/80 origin of T3 hormone in the body. It also disproves that view that, on average, our T3 supply arises from a 20:80 secretion to conversion ratio. The reality is more wide-ranging and diverse. It also reveals the flexibility of the healthy HPT axis.
My own main interest is almost always what the science means to proper and effective thyroid treatment. Well, it will be obvious to the reader who reads the summary that Dr. Smith has written and the full article that for some people who are on thyroid treatment Levothyroxine (T4) therapy is never, ever going to work. It should also be clear that for some people the loss of some or all of the thyroid through Hashimoto’s, thyroidectomy, or other adverse conditions, that simply adding a little T3 to the T4 treatment is also never going to be enough.
The diversity of individuals is such that some are far more reliant on their thyroid gland to compensate for poor peripheral tissue conversion than others. When these people develop a thyroid condition they will only ever return to being healthy by being given a significant amount of T3 in their treatment. Well, of course, many of us are well aware of the variation between people, but sadly the majority of the medical profession operates as if all our thyroid glands and thyroid hormone processing are identical. We are treated as if we are identical robots that have come off a production line. This is not true as the article carefully and methodically explains.
One of the big implications of the article to me is that T3 (Liothyronine) treatment must always be an option available for use if the patient does not respond symptomatically to T4 treatment. We really do need a new paradigm for thyroid treatment. The old one is utterly broken and leaves many thyroid patients highly symptomatic and in some cases extremely ill.
The article is quite long and has three separate parts to it. It is definitely worth spending the time to read it. However, Dr. Smith has also kindly written a summary of the article for those who are short of time or want a good idea of what it is about before reading the full version.
Here’s the link Dr. Smith’s summary of the article:
Here is the full article (but it is also linked from the summary above):