[QUOTE=Alexander]The thing is though is that if there is RT3 dominance, adding a medication which contains T4, even armour, will make a person more hypothyroid instead of increasing metabolism by converting t4 into rt3 instead of t3.
My total testosterone is within range but in the lower end of normal.[/QUOTE]
Since the lab tests given do not give Total T4, Total T3, nor Reverse T3, it would be difficult to argue that there is “RT3 Dominance.” If Total T3 is good, then one can’t argue that it is a problem with Reverse T3, either. Thus these other values are important to know.
Using only Free T3 and/or Free T4 as measures of thyroid signaling activity is flying blind since one doesn’t know the actual amount of thyroid hormone available nor the amount of binding proteins, which can be affected by other factors. Thus, at least a Total T4 is needed, and a Total T3 would be a bonus. Having these values would allow one to determine dosing.
Using TSH as a measure also assumes the brain is working well. If a person has mental illness and possibly other health problems, this assumption is incorrect. Thus TSH could be very off. Thus, correlating the physical signs and history of illness with the lab test becomes very important. One has to answer the question: “Is this patient physically hypothyroid?” This information is more important than the lab test itself.
If Free T3 is used as a measure of thyroid activity, then a level over 3.3 would usually mean a person has enough thyroid hormone. But because the brain conversion of T4 to T3 may be different from the body’s levels, a person could still be hypothyroid as far as the brain function is concerned yet look like they are good in thyroid hormone elsewhere. This is actually one of my explanations for the phenomenon of “Thyroid Resistance” that Dr. Lowe (drlow.com) believes as one contributing cause of Fibromyalgia. He would advocate adding T3 under this circumstance.
Under “normal” circumstances, about 40% of T4 is converted to T3 and 60% is converted to Reverse T3. Reverse T3 is very quickly removed from the system. It is the primary pathway that one gets rid of excess T4. Reverse T3 is quickly converted to T2 and T1 – which have some thyroid signaling activity – then to Tyrosine.
When one is fasting, has significant stress, or has significant physical illness (e.g. serious infection, etc., then TEMPORARILY (for about 1-3 weeks), T4 to T3 conversion is reduced and T4 to Reverse T3 conversion is increased. After 3 weeks, generally, T4 to T3 conversion returns to normal. The slower metabolism that results from lower T3 levels would also result in reduced elimination of Reverse T3, leading to the ILLUSION that there is even more Reverse T3 being created but this is actually due to reduced elimination of Reverse T3.
Note that this is temporary. Wilson’s Syndrome is the belief that this is not temporary – instead that it is stuck – but it can be reverted to the normal state by temporary T3 treatment. There isn’t much evidence for this, but I keep a open mind though have doubts. However, in psychiatry, the addition of T3 to augment antidepressant treatment is often a temporary maneuver also. Perhaps the improvement in mental function that can result from adding T3, reduces stress signaling enough that T4 to T3 conversion can be returned to normal.
This discussion, however, begs a huge question:
If fasting/starvation/poor nutrition, stress, or physical illness is the cause of the decreased T4 to T3 conversion, why not address these problems first?
For example:
1. Improve nutrition.
2. Improve one’s psychological skills to reduce stress by learning meditation or participating in psychotherapy
3. Reduce one’s environmental stresses (e.g. work, relationships, drug abuse, etc.)
4. Look for and treat the other physical illnesses or conditions one has which are not directly related to thyroid hormone, which impair conversion.
5. Improving one’s physical health through exercise.
Adding T4 generally does not result in hypothyroidism unless the replacement dose is too low. It is still converted to T3 and Reverse T3. The question would be if it works well if the person has other ongoing problems – such as different conversion rates in the body vs. brain. In the large majority of people, it works. It is also safer when adrenal fatigue is present, when nutritional deficiencies are present, etc. And it is cheap – $4 a month on Wal-Mart’s and Target’s prescription plans. In some patients, if T4 is used, the dose may have to be fairly high to obtain the desired results. The main problem is that as the person’s health improves, T4 to T3 conversion improves. The high dose T4 then increases the risk of hyperthyroidism since it would be an overcorrection. Thus, I would have to gradually reduced the dose of thyroid hormone used. Using Total T4 as a top end helps determine this line. One tactic is to reach a target Total T4 level and then work on the other areas of one’s health. As one then improves by addressing these areas, thyroid activity improves also. One can see temperature improve, for example, yet the dose of T4 remains the same.
As an aside, I generally would not do testosterone replacement on a man with a total testosterone of 500 ng/dl and above. What problems the person has are usually elsewhere and not due to testosterone deficiency. Addressing these other problems may actually lead to a rise in testosterone production.
Dr. M