LOW TSH LOW FT4 and LOW FT3

[colmca]

I was diagnosed with hypothyroidism two years ago and have been on synthroid since. My current dose is 100mg and I still feel awful. Terrible brain fog, constantly tired, and depressed. My latest blood test came back as follows:  TSH 1.095 with a range of .5 to 5, FT4 1.02 with a range of .89-1.76, and FT3 2.6 with a range of 2.3-4.2. My question is if my TSH is low shouldn't my FT4 and FT3 be at least in the middling range? Does this indicate a possible pituitary issue instead?  Thanks for any help that you can give me.

[gimel]

There are a number of good scientific studies that prove that TSH often becomes suppressed when taking thyroid medication adequate to relieve symptoms.  Here are some info and links that you might find useful for discussion with doctors.


Many doctors, and especially Endos, will tell you that TSH is basically all they need to diagnose and treat a hypothyroid patient.  That is very wrong.  
Although TSH is supposed to accurately reflect the thyroid status of a patient, TSH cannot be shown to correlate well with either of the biologically active thyroid hormones, Free T3 or Free T4, much less correlate with symptoms, which should be the main concern.  

In this link you can see just how poorly TSH correlates with Free T3 and Free T4.  If the correlation was good you could take a TSH level and predict what the Free T3 or Free T4 would be.  Clearly that is impossible because the correlation is so poor.  So what is it that TSH is supposed to reveal?  Not very much if you look at fig. 2 in the following link and also read through the additional links.

http://www.clinchem.org/content/55/7/1380.full

In addition, it is quite common for TSH to become suppressed when taking enough thyroid medication to become euthyroid clinically.  That does not mean you have become hyper, unless you do have hyper symptoms due to
excessive levels of Free T3 and Free T4/  But if FT3 and FT4 are within range, how can a doctor claim you are hyper based on TSH, which doesn't correlate with either FT3 or FT4 or symptoms.


http://www.ncbi.nlm.nih.gov/pubmed/3687325

"We found no correlations between the different parameters of target tissues and serum TSH. Our findings are in accordance with a cross sectional study showing only a modest correlation between TSH and the percentage of positive hypothyroid symptoms4 "


http://www.bmj.com/content/326/7384/311

"As a single test, serum TSH is therefore not very useful for the assessment of adequate thyroxine dosage in patients with primary hypothyroidism."

http://www.bmj.com/content/293/6550/808

T"o establish their role in monitoring patients receiving thyroxine replacement biochemical tests of thyroid function were performed in 148 hypothyroid patients studied prospectively. Measurements of serum concentrations of total thyroxine, analogue free thyroxine, total triiodothyronine, analogue free triiodothyronine, and thyroid stimulating hormone, made with a sensitive immunoradiometric assay, did not, except in patients with gross abnormalities, distinguish euthyroid patients from those who were receiving inadequate or excessive replacement. These measurements are therefore of little, if any, value in monitoring patients receiving thyroxine replacement."

http://www.ncbi.nlm.nih.gov/pubmed/1366242

"When TSH was suppressed, FT4 was elevated in 30.4% but normal in 69.6% of patients."
Suppression of TSH by thyroid replacement to levels below 0.1 mU/L predicted euthyroidism in 92% of cases, compared to 34% when TSH was above 1 mU/L (p < 0.0001). In conclusion, in central hypothyroidism baseline TSH is usually within normal values, and is further suppressed by exogenous thyroid hormone as in primary hypothyroidism, but to lower levels. Thus, insufficient replacement may be reflected by inappropriately elevated TSH levels, and may lead to dosage increment.


http://www.ncbi.nlm.nih.gov/pubmed/12481949

[Dustygirl01]

Unfortunately that's the problem...drs see the low tsh and say "you're over medicated!!" Even though ft4 and ft3 aren't high enough for us. So frustrating.

[gimel]

From those symptoms and your test results from the start, I'd say definitely you have central hypothyroidism, which is a dysfunction in the hypothalamus/pituitary system that results in inadequate TSH to properly stimulate the thyroid gland.  Even though you are taking thyroid med, the dosage is not enough to adequately raise your Free T4 and Free T3 levels.  

Your latest Free T4 was only at about 23% of its range, and your Free T3 was only at about 16% of its range.  Both are much too low for many people.  Members say that relief from hypo symptoms required Free T4 at the middle of its range, and Free T3 in the upper third of its range, or as necessary to relieve symptoms.  With central hypothyroidism it is most likely that by the time you reach adequate levels your TSH will be suppressed below range.  If so, don't let the doctor erroneously assume that you are hyper.  You are hyper only if having hyper symptoms due to excessive levels of FT4 and FT3.

You can get some good insight from this link written by a good thyroid doctor.

http://www.hormonerestoration.com/Thyroid.html

Also be sure to test for Vitamin D, B12 and ferritin and supplement as needed to optimize as shown above.  

[colmca]

Hi Gimel. My symptoms before I started treatment were exhaustion, weight gain, depression, hair loss, brain fog, headache, irritability, dry skin, muscle and joint pain, rapid deterioration of eyesight, no energy or concentration, feeling light headed, problems with finding right words, vertigo. The synthroid always made me feel a little bit better but never good. I am back to feeling all the same symptoms. My doctor has been the same throughout this time.

[Dustygirl01]

Colmca:  Yeah, my tsh was insanely low...like .66 or something prior to starting on Synthroid.  My T4 was .88 and my T3 was about normal.  Oddly enough after being on Synthroid for awhile my TSH was still about the same...around .55 but my TSH was up around 1.1 or so.  My meds were bumped AGAIN because I still feel like cr*p.  Now my TSH is super low...0.03 and my T4 is 1.27.  One time I had blood work done and my TSH was 1.2 though and my T4 was at the 50% area.  So, it fluctuates I guess.

[gimel]

While I am reviewing those results, please tell me about symptoms when you first started treatment and any symptoms you have now.  Also, was your doctor the same one through all of this?  

[colmca]

Thanks for your reply Dustygirl01. If I am reading your post correctly, your numbers were like mine but worse but before you started any threatments? Are you currently taking meds and have your numbers come into range?

[colmca]

Hi Gimel. Thanks again for your reply. Before starting synthroid  in May of 2013, my TSH was 1.36 and FT4 was .89.

After taking initial starter dose of medicine, in July 2013 TSH was 1.1 and FT4 was .92 and FT3 was 3.5 and my cortisol total was 20.2 in a range of 4.6-20.6. My synthroid was then increased to 75mg.

The next blood test in September 0f 2103 my TSH was .505 and FT4 was 1.25 and glucose was 78. My synthroid was kept the same.
February of 2014. My TSH was 2.346 and FT4 was 1.18. Dose was increased to 100mg.

April 2014 my TSH was .6 and FT4 was 1.2.

In November 2014 my TSH was .928 and FT 4 was 1.16 and Insulin was 4.0 in range of 3-17. Same meds.

In January 2015 TSH was 1.251, Glucose was 82 and FT 4 was not checked at that time. I am still on 100mg of synthroid.

July 2015 was TSH 1.095, FT4 was 1.02 and FT3 was 2.6.

Thank you so much for any advice that you can offer!

[Dustygirl01]

I was like you prior to starting thyroid meds...my TSH wasn't really high at all considering how low everything else was.  My TSH was even lower than yours.  My system was literally not doing anything.  Sometimes the "feedback axis" just doesn't work right.  Sometimes I guess it's a pituitary issue.  Stress, meds, illness, etc. can all influence it as well.

[gimel]

Serum thyroid hormone levels are comprised of natural thyroid hormone from the gland and also any thyroid med you are taking.  As you start taking thyroid med, the TSH level will be diminished and the output of natural thyroid hormone also reduced.  Frequently a hypo patient will see little or no change in serum levels until meds are increased enough that the TSH becomes suppressed and the serum level is totally dependent on thyroid med.  

All the things you read and talked about apply only before starting on thyroid med.  After starting on thyroid med, the TSH is basically a useless test.  What were your TSH, Free T4 and Free T3 before starting on thyroid med?

[colmca]

Can someone explain to me why my TSH would be on the low normal side and my FT4 and FT3 are also on the low normal side? I thought if my TSH was low, my FT4 and FT3 should be higher? I have found charts on the internet that say low/normal TSH, FT4 and FT3 indicate secondary or central hypothyroidism. Is this correct and if so does central hypo indicate a possible pituitary/hypothalamus problem? My D is 31.5 in a range of 30-100, my iron is 68 in a range of 50 to 170 and glucose is 76 in range of 74-106.

[gimel]

The body normally converts T4 to T3.  If conditions are adequate for good conversion, then a T4 med will work.  Under some circumstances conversion may be inadequate, and a med containing T3 becomes necessary, in order to raise the Free T3 level enough to relieve symptoms.  Adequate ferritin is  important to conversion of T4 to T3.  That is why I include it in additional tests that should be done.  

There are a number of meds containing T3:  The desiccated types that include Armour Thyroid, NatureThroid, and Erfa Thyroid.  Then there is Cytomel, or generics, which are only T3.  

[colmca]

Thanks gimel. You mentioned that the endo should be adjusting FT4 and FT3. Doesn't synthroid only affect your FT4? What medicines would adjust FT3?

[gimel]

There is nothing at all to indicate a possible pituitary issue.  A TSH test is of little value when already taking thyroid meds.  The reason you are still having symptoms is that your Free T4 and Free T3 are still too low in the range.  Both are only at about 15 % of their range.  Many members say that symptom relief required Free T4 at the middle of its range, at minimum, and Free T3 in the upper third of its range, or as necessary to relieve symptoms.  So you need to continue to gradually increase your thyroid med to achieve symptom relief.  

A good thyroid doctor will treat a hypo patient clinically by testing and adjusting Free T4 and Free T3 as necessary to relieve symptoms, without being constrained by resultant TSH levels.  Symptom relief should be all important, not just test results, and especially not TSH results.  I say that because TSH frequently becomes suppressed below range when taking adequate thyroid medication to relieve symptoms.  That does not mean that you are then hyperthyroid, unless you do have hyper symptoms due to excessive levels of Free T4 and Free T3.  So keep that in mind and don't let the doctor become alarmed if your TSH becomes suppress in order to sufficiently raise your Free T4 and Free T3 levels.  

Last for now, hypo patients are frequently too low in the ranges for Vitamin D B12 and ferritin.  Be sure to test those and supplement as necessary to optimize.  D should be about 55-60, B12 in the upper end of its range, and ferritin about 70 minimum.  Very important for a hypo patient.