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Why add T3 meds?
Hi,
As a hypo patient, taking t4 meds for a few months now, I have a question regarding t3&t4 meds.
Do patients who switch to a combination usually do it due to a poor FT4 to FT3 ratio? (as in FT4 at the top of the range and FT3 below mid-range) or due to a different biological effect that the T3 meds have? or both?
In my case, for instance, the ratio between my FT4 & FT3 is pretty much 1:1 (FT3 is in the 44 percentile of the range and FT4 is in the 48). Is it an indication that I should continue raising my T4 dosage until they're both at the top of the range (and constantly considering my symptoms, of course)?
Or are there more reasons for adding FT3 meds, aside from raising the FT3 indice, such as its more direct influence?
As a hypo patient, taking t4 meds for a few months now, I have a question regarding t3&t4 meds.
Do patients who switch to a combination usually do it due to a poor FT4 to FT3 ratio? (as in FT4 at the top of the range and FT3 below mid-range) or due to a different biological effect that the T3 meds have? or both?
In my case, for instance, the ratio between my FT4 & FT3 is pretty much 1:1 (FT3 is in the 44 percentile of the range and FT4 is in the 48). Is it an indication that I should continue raising my T4 dosage until they're both at the top of the range (and constantly considering my symptoms, of course)?
Or are there more reasons for adding FT3 meds, aside from raising the FT3 indice, such as its more direct influence?
"If I see that my FT4 is getting into the 50% of the range and my FT3 is about the same, is it time to stop raising the T4 dosage and adding T3?"
Not necessarily. Many of us found that FT3 continued to rise once FT4 was stable. There's a whole process that your body has to go through once FT4 levels are good: conversion has to ramp back up, your body has to heal. However, if FT4 levels have been stable through a couple of labs, FT3 isn't going up, and you still don't feel well, then it's time to try adding in some T3.
"Can't I raise the T4 med until both FT4 and FT3 are at the 75% of the range?"
75% of range for FT4 is too high for many people. And, just because your FT4 is 75% of range doesn't mean that FT3 will be. If you don't convert well, FT3 will remain low despite higher FT4 levels. Rule of thumb for the relationship of FT3 to FT4 is that FT3 should be higher in its range than FT4 is in its. So, at 50% FT4, we'd expect to see upper half to upper third of range IF you convert well. People who convert slowly can't raise their FT3 levels with just the addition of more T4.
If I interpret correctly, you've been on T4 for only a few months? What were your FT3 and FT4 levels before starting meds? Have they improved? Have your symptoms improved at all?
Not necessarily. Many of us found that FT3 continued to rise once FT4 was stable. There's a whole process that your body has to go through once FT4 levels are good: conversion has to ramp back up, your body has to heal. However, if FT4 levels have been stable through a couple of labs, FT3 isn't going up, and you still don't feel well, then it's time to try adding in some T3.
"Can't I raise the T4 med until both FT4 and FT3 are at the 75% of the range?"
75% of range for FT4 is too high for many people. And, just because your FT4 is 75% of range doesn't mean that FT3 will be. If you don't convert well, FT3 will remain low despite higher FT4 levels. Rule of thumb for the relationship of FT3 to FT4 is that FT3 should be higher in its range than FT4 is in its. So, at 50% FT4, we'd expect to see upper half to upper third of range IF you convert well. People who convert slowly can't raise their FT3 levels with just the addition of more T4.
If I interpret correctly, you've been on T4 for only a few months? What were your FT3 and FT4 levels before starting meds? Have they improved? Have your symptoms improved at all?
COMMUNITY LEADER
Just to put my 2 cents' worth in here --- FT3 should be higher in its range than FT4 is, in its. That's why the rule of thumb for FT4 is about mid range, while the rule of thumb for FT3 is upper 1/2 to upper 1/3 of its range.
Also be aware that T3 med is much stronger than T4 med, so a little can go a long way.
Also be aware that T3 med is much stronger than T4 med, so a little can go a long way.
appreciate the answers!
If I see that my FT4 is getting into the 50% of the range and my FT3 is about the same, is it time to stop raising the T4 dosage and adding T3?
Can't I raise the T4 med until both FT4 and FT3 are at the 75% of the range?
If I see that my FT4 is getting into the 50% of the range and my FT3 is about the same, is it time to stop raising the T4 dosage and adding T3?
Can't I raise the T4 med until both FT4 and FT3 are at the 75% of the range?
I agree with goolarra that the ranges for FT3 and FT4 are flawed. The reason for that is the erroneous assumptions made when establishing the ranges. The ranges are based on the total population of patients tested. Of course, without screening, that would include hypo and hyperthyroid participants. Then the assumption was made that about 2.5% were hypo and similar for hyper, and the range limits drawn at those points. The percentage of hypothyroid patients is obviously much, much larger than that. So the ranges are skewed greatly toward the low end.
Having some training in statistical analysis, I estimated some time ago that a more correct range for Free T3 would be 3.3 - 4.3 pg/ml, and for Free T4 1.0 - 1.55 ng/dl. There are numerous sources that are in agreement directionally. Here is one quote from a good thyroid doctor, " the 95% statistical range would be 1.3 to 1.6ng/dL". Also, following is the conclusions from a related scientific study.
"High individuality causes laboratory reference ranges to be insensitive to changes in test results that are significant for the individual.
The width of the individual 95% confidence intervals were approximately half that of the group for all variables.
Our data indicate that each individual had a unique thyroid function. The individual reference ranges for test results were narrow, compared with group reference ranges used to develop laboratory reference ranges. Accordingly, a test result within laboratory reference limits is not necessarily normal for an individual."
Andersen S, Pedersen KM, Bruun NH, Laurberg P. Narrow individual variations in serum T(4) and T(3) in normal subjects: a clue to the understanding of subclinical thyroid disease. J Clin Endocrinol Metab. 2002 Mar;87(3):1068-72.
Keeping all the above in mind, it is easier to understand why clinical treatment is most effective, rather than treatment by "Reference Range Endocrinology". since most people have their own unique thyroid function. It is also easier to understand why most members say that symptom relief for them required Free T3 in the upper third of the range and Free T4 around the middle of its range.
Having some training in statistical analysis, I estimated some time ago that a more correct range for Free T3 would be 3.3 - 4.3 pg/ml, and for Free T4 1.0 - 1.55 ng/dl. There are numerous sources that are in agreement directionally. Here is one quote from a good thyroid doctor, " the 95% statistical range would be 1.3 to 1.6ng/dL". Also, following is the conclusions from a related scientific study.
"High individuality causes laboratory reference ranges to be insensitive to changes in test results that are significant for the individual.
The width of the individual 95% confidence intervals were approximately half that of the group for all variables.
Our data indicate that each individual had a unique thyroid function. The individual reference ranges for test results were narrow, compared with group reference ranges used to develop laboratory reference ranges. Accordingly, a test result within laboratory reference limits is not necessarily normal for an individual."
Andersen S, Pedersen KM, Bruun NH, Laurberg P. Narrow individual variations in serum T(4) and T(3) in normal subjects: a clue to the understanding of subclinical thyroid disease. J Clin Endocrinol Metab. 2002 Mar;87(3):1068-72.
Keeping all the above in mind, it is easier to understand why clinical treatment is most effective, rather than treatment by "Reference Range Endocrinology". since most people have their own unique thyroid function. It is also easier to understand why most members say that symptom relief for them required Free T3 in the upper third of the range and Free T4 around the middle of its range.
Please post your FT3 and FT4 results with reference ranges. It's a lot easier to talk about this with actual numbers to refer to.
People who swicth to a combo usually do so because their FT3 doesn't track their FT4 up, indicating slow conversion, and their symptoms remain. However, there are many factors at work. For example, once FT4 gets to approximately midrange, it often takes FT3 a while to "catch up", i.e. FT3 levels will often keep rising once FT4 levels are stable since it takes time for conversion to ramp back up once FT4 levels are adequate. Also, once both levels are adequate, it takes the body time to heal (commensurate with the amount of time that you were hypo and the number of symtoms you'd acquired).
Very few people have to have FT3 and FT4 at top of range. Most of us will be hyper before that. The rules of thumb are FT4 at midrange and FT3 upper half to upper third of range. Though the ranges are quite flawed, keep in mind that the middle of each range is the "most normal", with the tails trailing toward hypo and hyper.
T3 does have a more direct influence. Some people seem to feel better with the addition of just a small amount of it. Healthy human thyroids produce a T4:T3 ratio of about 20:1; the rest of T3 comes from conversion.
People who swicth to a combo usually do so because their FT3 doesn't track their FT4 up, indicating slow conversion, and their symptoms remain. However, there are many factors at work. For example, once FT4 gets to approximately midrange, it often takes FT3 a while to "catch up", i.e. FT3 levels will often keep rising once FT4 levels are stable since it takes time for conversion to ramp back up once FT4 levels are adequate. Also, once both levels are adequate, it takes the body time to heal (commensurate with the amount of time that you were hypo and the number of symtoms you'd acquired).
Very few people have to have FT3 and FT4 at top of range. Most of us will be hyper before that. The rules of thumb are FT4 at midrange and FT3 upper half to upper third of range. Though the ranges are quite flawed, keep in mind that the middle of each range is the "most normal", with the tails trailing toward hypo and hyper.
T3 does have a more direct influence. Some people seem to feel better with the addition of just a small amount of it. Healthy human thyroids produce a T4:T3 ratio of about 20:1; the rest of T3 comes from conversion.
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