There is a simple reason why doctors typically refuse to prescribe the T3 thyroid hormone and it has nothing to do with science, side-effects, or potential dangers.
As with so many things in healthcare, it boils down to Big Pharma and money. The solution is to find a better-informed doctor.
Mark
February 26, 2019 at 6:01 pmGreat topic that need to be fleshed out.
I am not at all against natural dessicated thryoid (NDT) at all, and in fact, have been slowly increasing my dose of NDT slowly from 1 grain to 1.5 grains, however, I wanted to get your thoughts on this:
Since NDT has a 4.22:1 ratio of T4 to T3, it has prompted many in the alternative medical community to warn against prescribing it because it does not fall within the physiologic ratios found in the human thyroid gland as shown in many studies and thus contains too much T3 relative to T4. Here’s an excerpt from one such study:
“The molar ratio of T4 to T3 in the human thyroglobulin is 15:1, and some estimates put the thyroidal secretion as containing a molar ratio of 11:1, which is supportive of thyroidal deiodination of T4.”
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4699302/
From practitioner blogs:
“…When taking an RX of Thyroid Hormone Replacement from porcine or another animal, the ratio of T3 to T4 is not what we have in our human bodies. In fact the T3 is way too high, and thus the cell membrane, doing its work, shuts down admittance of more of this hormone, becoming resistant– and the Free T3 can be seen as high, or even very high, influencing of course the levels of T4 and TSH, even when the person’s complaints are exceeding fatigue, hair loss, and other hypothyroidism symptoms. This is very confusing not only to the patients, but to their health practitioners.”
http://www.integrativeholistichealth.org/information/natural-dessicated-thyroid-ratio-t4-to-t3-causing-illness/
“Dr Dayan prefers a T4:T3 ratio of (14:1) because this closely matches the natural secretion rate for T4 and T3 by the human thyroid gland:
The doses (for NDT) give a T4:T3 ratio of 4.2:1, significantly more T3 than the 14:1 secreted by the normal thyroid and the doses recommended above. This makes dosing difficult as displayed by several studies which have shown supraphysiological T3 doses post dose, fluctuating T3 levels during the day and more hyperthyroid symptoms in subjects taking DTE compared to LT4 monotherapy.”
“Furthermore, it has also been shown that the majority of circulating T3 comes from peripheral conversion of T4 to T3 and not secretion of T3 from the thyroid [8], hence a T4:T3 secretion ratio of approximately 14:1 appears average in humans, suggesting only a small role for secreted T3.”
“Practicing clinicians will be able to identify a group of patients not satisfied on LT4 monotherapy which makes up a small subset of all their patients on LT4…. Both ATA and ETA suggest that in an appropriate clinical setting (see below) combination therapy may be trialed to determine if it is beneficial for the individual patient [5, 6]….despite recommendations and guidelines from various specialist bodies,use of combination T4/T3 therapy appears significant in most developed countries.”(37)”
“To replicate normal thyroid gland physiology, both T4 and T3 should prescribed in a ratio tailored for each patient.”
“…When taking an RX of Thyroid Hormone Replacement from porcine or another animal, the ratio of T3 to T4 is not what we have in our human bodies. In fact, the T3 is way too high, and thus the cell membrane, doing its work, shuts down admittance of more of this hormone, becoming resistant– and the Free T3 can be seen as high, or even very high, influencing of course the levels of T4 and TSH, even when the person’s complaints are exceeding fatigue, hair loss, and other hypothyroidism symptoms. This is very confusing not only to the patients, but to their health practitioners.”
“On average, a normal human produces about 100 mcg T4 and 6-10 mcg of T3 daily. 30 mg of Armour only has 19 mcg T4 and 2.25 mcg T3, so you really could become more hypo by taking a low dose of thyroid medication.”
https://jeffreydachmd.com/2018/10/which-thyroid-natural-synthetic-combination/
Then there’s the Listecki-Snyder Protocol:
Commercial combinations of T4/T3 such as Armour Thyroid and Nature-Throid have a 4.22:1 T4:T3 ratio. Applying the same concept as bioidentical hormone replacement therapy, compounding pharmacists can deliver an 11:1 ratio using a commercial T4 product and taking into account oral bioavailability of each entity.
The short half-life of T3 can be remedied by taking the patient’s daily T3 dose and dividing it into two slow-release capsules to be dosed every 12 hours.
https://www.ncbi.nlm.nih.gov/pubmed/23072197
Major Objection to NDT – High peak T3 levels
BOTTOM LINE:
So, in the end, does the purported human thyroid ratio shown in studies really matter when —
a) everyone’s hormone production vary so widely in different organs and tissues and there’s really no way to quantify it?
b) roughly 15% of the population has an inborne deiodinase polymorphism causing an inability to adequately convert T4 to T3 in which case they may do better on more T3 and Less T4 (as with NDT) – or in severe cases, T3 monotherapy?
c) the majority of mainstream endos refute BOTH the clinical significance of T4/T3 conversion defects
and thus the use of combination therapy (i.e. NDT, T4/T3) and T3 monotherapy and warn against the deleterious effects of T3 replacement: https://hormonesdemystified.com/t3-or-not-t3-tough-question
“After longer periods of time, the heart may go into a dangerous rhythm called atrial fibrillation, the bones may become more fragile and prone to fracture, and muscles may waste.”
They also warn that using serum FT3 tests are not relevant because “the T3 level in your blood does not correlate well with the T3 level in all your various tissues. Remember, each organ is making its own T3 based on its needs at that moment. We can’t measure that.”
Even wikipedia warns about too much T3 in NDT:
“Concerns include the potential for adverse effects from superphysiological levels of T3 and the absence of long-term safety data from randomized clinical trials.”
“it seemed wiser not to bypass this control system by providing larger amounts of T3 than were naturally produced each day”
“it was discovered that thyroid extract and synthetic combinations of T4 and T3 produced significantly greater fluctuations of T3 throughout the day than occurred in healthy people or hypothyroid people treated with thyroxine alone.”
https://en.wikipedia.org/wiki/Desiccated_thyroid_extract
Thoughts?
Bob Niland
February 26, 2019 at 7:27 pmMark wrote: «Great topic that need to be fleshed out.»
Be aware that including more than one link in a reply, on most WordPress blogs, will toss the reply into moderation. I don’t know that Dr. Davis will respond, but I have some observations based on family cases.
re: «Since NDT has a 4.22:1 ratio of T4 to T3, it has prompted many in the alternative medical community to warn against prescribing it because it does not fall within the physiologic ratios found in the human thyroid gland as shown in many studies and thus contains too much T3 relative to T4.»
Yet consensus med wants to prescribe T4 only, and monitor it with TSH only, or perhaps TT4, and less frequently fT4. That sobering observation aside (and familiar to you, I’m sure), program guidance here is to monitor a real thyroid panel: fT3, rT3, fT4, TSH, symptoms, supplement iodine to optimal levels, and get periodic antibody tests to keep an eye on any auto-immune involvement.
re: «…and the Free T3 can be seen as high, or even very high, influencing of course the levels of T4 and TSH…»
And that’s why monitoring fT3, in the context of a full panel, is critical.
re: «This makes dosing difficult…»
Yes, it can be tricky, which might be part of why consensus sickcare tries to dumb it down to TSH & levo.
re: «“To replicate normal thyroid gland physiology, both T4 and T3 should prescribed in a ratio tailored for each patient.”»
That would be great, but entirely apart from dogmatic T4, there’s apparently some challenge with accurate and consistent compounding.
Bottom line: the fine-tuning you suggest would be wonderful to consider. But first, we need to eliminate utterly optional thyroid provocations, rectify the cases that are mere iodine deficiency, then parse the real cases into classes that include but are not limited to: hypo/hyper, AI/non-AI, look for frank morphological and etiological signs, then see which of those remain outliers after competent attempts to dial-in an appropriate thyroid hormone Rx. Alas, I don’t think I’m describing the Standard of Care here.
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Lynn
March 1, 2019 at 12:26 pmThank you, Dr. Davis. My husband has been following the Wheat Belly lifestyle for several years (no wheat, low carb., vitamin d, dha, magnesium, probiotics, prebiotics, etc., He tried to correct iodine deficiencies by following Dr. Amy Myers advice, but alas years of eating a high carb/wheat diet have done some kind of a number on his thyroid, so he’s starting on levothyroxine. I will refer him to your blogs. I’m also thinking of asking him to be the one named on the undoctored site because we support it, but he may get more out of utilizing it.