My View on Optimum Thyroid Levels

[telus2]

Here are my thoughts on a way to reach your optimum thyroid level. I would appreciate any comments that you might have on this.

The low and high numbers of the lab reference ranges represent the 2.5 and 97.5 percentile values, so they capture 95% of the population. But they do not tell you what level the majority of normal people are at. If you look at a frequency distribution graph for a particular lab test, the vast majority of people are around the median. The definition of median is that 50% of people are lower and 50% are higher - so it's right in the middle.

You might say "why not just use the mid-point of the range?" The answer is that the reference range is for the total population, but in fact they should use a number of different reference ranges based on age and gender. And hence the medians are different based on age and gender (especially for young people).

I have searched for median values for TSH, FT3, FT4, TT3, TT4, RT3 and found them in a number of papers on the web (I give the reference for one good paper below).

Many people coming to this board are new to thyroid problems, so as a FIRST STEP ON THEIR WAY TO THEIR WAY TO THEIR OPTIMUM VALUE  I suggest that people target the median values for their labs - because that is where the vast majority of people with normal thyroids are at. And give the meds a good long time to see if it will work at this level.

There are 3 reasons why I suggest stopping at this level as a first step:

(1) Because people have a tendency to increase their dose too soon. They are impatient because they are not feeling good. But the fact of the matter is that it takes 4 to 5 weeks for T4 to get up to full dose after a change, and then further time should be allowed after that for the body to adjust to the medicine at full dose.

(2) A great many people do not have thyroid problems only - they often have other problems as well. For example they often have adrenal problems induced by the thyroid problems. So these problems have to be given time to resolve or to be treated. Great care must be taken that these problems are not mistaken for low thyroid levels and used as the reason to increase the thyroid doses.

(3) Because taking too high doses is just as bad as taking too little! The higher your blood levels of T4, the higher the levels of Reverse T3 (RT3) that you will have. Taking too much T4 will lead to build-up of RT3 to above normal. RT3 blocks the action of T3. If you take too much T4/T3, you will have upper range levels of FT3 and FT4 in your blood labs - but you will feel very hypothyroid if your RT3 is too high, because your T3 cannot do its job properly.

There are far too many people who have increased their thyroid meds too fast and continue to suffer because of it. Far too many patients and doctors are completely unaware of RT3 and the problems it causes and of course don't order a RT3 lab test. If we can prevent people from getting into this problem, I think we should do it.

So that's what I think should be the first step - a long time, and make sure every thing else is working right. Then if you still have hypothyroid symptoms, then cautiously increase the meds and once again give it a good long test. Keep doing this until you reach your optimum level.

Table 1 of the following paper has median values for males and females under and over 60 years. Use the values for "euthyroid controls".

"Levothyroxine monotherapy cannot guarantee euthyroidism in all athyreotic patients."
Gullo D, Latina A, Frasca F, Le Moli R, Pellegriti G, Vigneri R.

On Table 1, the median values for females under 60 are:
TSH 1.40
FT4  13.4 pmol/L or 1.04 ng/dL
FT3  4.44 pmol/L or 2.88 ng/dL

On Table 1, the median values for males under 60 are:
TSH 1.30
FT4  14.2 pmol/L or 1.10 ng/dL
FT3  4.79 pmol/L or 3.11 ng/dL

thanks.

[telus2]

Lady and Gentlemen,
Thank you for your responses. A lot of good points. I will respond.
Thx.

[flyingfool]

If "we" can only get Dr's to disregard TSH as being the best tool in medicine since the invention of antibiotics that would be a great first start!

If the we could get Dr's to treat a patient by slowly raising FT4 levels to mid point and continually monitoring the patients symptoms as a first step that would be a major breakthorugh. And not simply rely upon the patient having an FT4 level that is at rock bottom of the range.  Then determiing if a source of T3 is needed.

I agree that the reference ranges are too broad.  Clearly this forum wouldn't exist if the ranges were purged of suspected tested individuals who may have thyroid issues. But I don't see that ever happening.

I really would like to know how the labs get these data points anyhow for their lab reference ranges?

Do they simply take the data from whatever tests they conduct and THEN take and throw out the top and bottom 2.5%.  If so this is VERY skewed.  Think about it. How many people who feel great get tested for Free T4 and Free T3?  I'd guess almost zero percent of the population.  The only people who would get tested are almost assuredly suffering thyroid related symptoms to even get a Dr to prescribe the FT4 and FT3 tests.  So right off the bat the entire range is DRAMATICALLY faulty. And this is exactly what I think is done for determining the ranges.

Secondly I will spit out my Pharmacudical conspiracy.  The Big Pharma companies make Billions of dollars in profit on drugs.  And the name of the game is selling more drugs.  And you tell me if it makes sense for Big Pharm to conduct R&D to determine new reference ranges which would result in them only selling one generic non proprietyary (read extremely low profit) thyroid hormone, versus selling the same patient six different medications to "cure" six different symptoms!

Also consider that we know that low thyroid is directly connected to high cholesterol. And low and behold the #1 money maker of big Pharma profits is proprietary (high profit) Statin drugs such as Lipitor, Crestor etc.  

Humm.  #1 money maker may get totally wiped out of profits if we just treat a lot of people/patients with break even costs thyroid hormone and they don't need their Lipitor anymore.  Hummmm

Follow the money.

We have all found medical research for decades that prove our points above.  yet Medical schools do not teach this fact.  Instead they are still hammering on TSH, TSH, TSH and refrence range endocrinology.  Gee I wonder if big Pharma donates huge amounts of cash for R&D and other grants and  donations to medical schools.  Humm I wonder why they don't revise their curriculum to teach the new Dr's about the research that would decimate the big Pharma profits. You know the same companies that donate to these schools.  Again follow the money!!!

Just my rant and my opinion. You're free to disagree.  That is what is great about this country  (at least so far).  I better watch out....I may be getting an IRS audit if I tick off the wrong entity.

[gimel]

From your posts and this thread, I think we have many areas of agreement, and a few areas where there are some things that need to be discussed.  The first area I would say is the concept of the reference range itself.  The ranges for TSH, Free T3 and Free T4 have been calculated in  a similar manner by the different labs and organizations.  The total data base for a particular test was analyzed statistically and the upper and lower limits were set based on the assumption of about 2.5% of the population being hypo and 2.5% being hyper.   Obviously this is way short of reality.  

So, over ten years ago the AACE finally acknowledged their error and purged their data base of suspect thyroid patients and recalculated the range for TSH.  The range changed drastically from .5 - 5.0 down to .3 - 3.0.  Unfortunately most labs and doctors still don't even recognize the change (or that TSH is totally inadequate as a diagnostic for thyroid anyway).  In addition, the ranges for Free T3 and Free T4 have the same built-in error, but those ranges have never been corrected like done for TSH.  

Having some background in statistical analysis, I estimated some time ago that if the data bases for Free T3 and Free T4 were similarly purged, the new ranges would be more like 3.2 - 4.3 Pg/ml for FT3 and 1.0 - 1.55 ng/dl for FT4.  I think these ranges better reflect what would be expected for healthy adults with no known thyroid pathology.  I have found sources that are in general agreement with this.  So, there is plenty of room to argue the exact numbers, but no room for argument that the current ranges are far too broad and don't really reflect results that would be expected for those healthy adults.

So, I have two concerns with talking about median values as a starting target.  First, I see no practical value for adding yet more confusion for members by using the concept of the median, rather than the midpoint of the range.   The patient will have the reference range shown on the lab report, and is familiar with the concept of midpoint.   In my view midpoint vs median is only a difference without a distinction, so why not use what is readily available and recognizable, since either is only a step along the way to achieving levels adequate to relieve symptoms.  

My second concern is that both the midpoint and the median are significantly below the predicted average for healthy adults, after the data bases are purged of patient data suspect of having thyroid pathology, so instead of either the midpoint or the median, to me targeting the upper third of the range for FT3 creates a better picture of what may ultimately be needed to relieve the patient's symptoms.  

I agree with goolarra that standard advice is 4-6 weeks to get full effect of T4 meds and we also say that symptoms tend to lag changes in serum levels of thyroid hormones.  When members are feeling really bad and their levels are really in the dumpster, I have no problem with speeding up the time interval to 4 weeks, but later when levels have been raised, we counsel members to take it slow and steady.  We also typically counsel that patience is vital for a hypo patient and that hyper is much worse than hypo, so make changes with caution.

On your item no. 2, I am in agreement with goolarra's statements.  

On your item no. 3 we agree about getting FT4 levels too high, with T4 meds.  If you have spent some time on the Forum, you will notice that we are quite alert to the problem of inadequate conversion of T4 med to T3 and the attendant problems when the doctor continues to increase T4 med while trying to drive the T3 level higher.   In those cases, we typically suggest additional testing and try to determine the existence of some of the normal causes for slow conversion.  We also typically alert the patient to the problem and suggest a reduction of T4 med and the addition of a source of T3 to the patient's meds.  

All in all, as I said, much agreement, and only a few areas where I would do things a bit differently.  I'm sure we all have the same major objectives.  I think it is good to have these discussions, and hopefully become overall more consistent with our advice because doing otherwise would serves to confuse and frustrate members.   JMHO

Best to you.  

[LazyMoose]

opps, I left out an important word

"  Raising daily thyroid med amount SLOWLY when starting any new thyroid med is important."

[goolarra]

FT3 and FT4 ranges are tainted.  "Normal" population included both asymptomatic people with Hashi's and symptomatic, but undiagnosed, people.  Ranges have never been adjusted, even after TSH range adjustment was recommended by AACE, in recognition of the flawed ranges.

Mean or median I believe is a bit of a moot point.  "Midrange" is nothing but a rule of thumb to give people a (very) rough idea of where they should be.  But, whether you use the mean or the median, population ranges do not apply to the individual.  With a range of 0.8-1.8 on FT4, for example, if you happen to be one of the outliers who is comfortable at one end of the curve or the other, midrange is just not going to work.  The rule of thumb really should be to increase meds until symptoms are relieved or hyper symptoms appear, whichever comes first.  If you become hyper, back off, give it some time, and look elsewhere if symptoms don't resolve.  I completely agree that moving slowly increases the probability of hypo symptom relief without the added joy of going hyper.

"But the fact of the matter is that it takes 4 to 5 weeks for T4 to get up to full dose after a change, and then further time should be allowed after that for the body to adjust to the medicine at full dose."

This is a standard recommendation on this forum.  

"A great many people do not have thyroid problems only - they often have other problems as well. For example they often have adrenal problems induced by the thyroid problems. So these problems have to be given time to resolve or to be treated. Great care must be taken that these problems are not mistaken for low thyroid levels and used as the reason to increase the thyroid doses."

Agreed, but great care must be taken also that they aren't influenced to chase other issues when an obvious thyroid issue is still unresolved.  This is where symptoms come in.

RT3 is a can of worms, both within the medical profession and within the forum!  RT3 dominance is not just caused by overmedication.  It can be cause by disease, stress, trauma, starvation (including extreme weight loss programs), surgery, etc.  It's the body's defense mechanism when times get rough.  It's only when RT3 dominance outlives the stressor that cause it that it becomes a problem.  

Finally, regarding the median levels for FT3 and FT4.:

On Table 1, the median values for females under 60 are:
TSH 1.40
FT4  13.4 pmol/L or 1.04 ng/dL
FT3  4.44 pmol/L or 2.88 ng/dL

On Table 1, the median values for males under 60 are:
TSH 1.30
FT4  14.2 pmol/L or 1.10 ng/dL
FT3  4.79 pmol/L or 3.11 ng/dL

You cannot discuss any of these values except in the context of the reference range that applies.  Reference range for FT3 was 1.88-3.9 ng/dl (2.9-6.0 pmol/L) and for FT4 was 0.7-1.6 ng/dl (9-20.6 pmol/L) for the methodolgy used in this paper.  Both are considerably lower (top and bottom) than the ranges we typically see.  That aside, the numbers you quote above would have to be adjusted for the individual's lab's ranges.   Median values are not readily available on a lab specific basis.    

[LazyMoose]

One thing to consider with the ranges developed from the general population. How healthy was the general population that was used for the study? We dont know.

Raising daily thyroid med amount when starting any new thyroid med is important. Going temporarily hyper if increasing to fast feels worse then being hypo, been there, done that. But, I can also look at my hyper experience, just as it was, experience knowing how I felt hyper. Now I know.

Going to the midrange and tying it there for a while is good for newbies, but if that doesnt work, then they must move on, weather it be thyroid, or other issues producing similar symptoms.

Here is an exception - when many people have FT3 in the midrange with hypo symptoms, they often feel better raising the FT3 to the upper third of the FT3 range, without feeling hyper. But yes, going right up to the upper third with out staying in the middle for a while realy doesnt make sense.

With any dessicated med, having FT4 and FT3 both in midrange is not possible, FT3 will always be higher.

In the end, Its all about patients and finding the right level per individual without taking to much replacement hormone, because we are all different, not just numbers.