Thyroid Disorders Community
normal TSH, low free T4
About This Community:

This patient support community is for discussions relating to thyroid issues, goiter, Graves disease, Hashimoto's Thyroiditis, Human Growth Hormone (HGH), hyperthyroid, hypothyroid, metabolism, parathyroid, pituitary gland, thyroiditis, and thyroid Stimulating Hormone (TSH).

Font Size:
A
A
A
Background:
Blank
Blank
Blank
Blank Blank

normal TSH, low free T4

Below are my lab levels.  I am on lithium carbonate.  Please explain!

TSH 2.900 uIU/mL (0.450-4.500)
Thyroxine (T4) 3.9 LOW ug/dL (4.5-12.0)
T3 Uptake 27 % (24-39)
Free Thyroxine Index 1.1 LOW (1.2-4.9 )
T4,Free(Direct) 0.73 LOW ng/dL (0.82-1.77)
Triiodothyronine,Free,Serum 2.7 pg/mL (2.0-4.4)

Do you treat the T4 even if the TSH is normal?  I have experienced 10lb weight gain in the past year in spite of eating better but perhaps this is a reflection of my age (35).  No other symptoms really to report.

Thank you so much in advance.
Blank
Avatar_f_tn
Many years ago, AACE recommended that TSH range be changed to 0.3-3.0.  As you can see, labs have been very slow to make the change.  Your TSH is in the very top of that range.

Total T4 and T3U are considered obsolete test of little value.

Your FT4 is below range, which means your thyroid isn't making adequate amounts.  FT3 is in the lower third of the range, and it belongs in the upper half.

TSH is a pituitary hormone and as such is affected by many factors other than thyroid hormone levels.  So, it's the least important of the thyroid tests, although doctors have been taught that it's the gold standard in thyroid testing.  FT3 correlates best with symptom, FT4 falls behind it, and TSH does not correlate at all.  So, the most alarming number there is your FT4, which is below range.  It can be difficult to find a doctor who will treat FT4 and ignore TSH.

It's the lithium:

http://www.ncbi.nlm.nih.gov/pubmed/9827658

How long have you been on lithium?  The study suggests that the hypothalamus/pituitary/thyroid axis might be "reset" when starting lithium.  
17 Comments Post a Comment
Blank
Avatar_f_tn
Many years ago, AACE recommended that TSH range be changed to 0.3-3.0.  As you can see, labs have been very slow to make the change.  Your TSH is in the very top of that range.

Total T4 and T3U are considered obsolete test of little value.

Your FT4 is below range, which means your thyroid isn't making adequate amounts.  FT3 is in the lower third of the range, and it belongs in the upper half.

TSH is a pituitary hormone and as such is affected by many factors other than thyroid hormone levels.  So, it's the least important of the thyroid tests, although doctors have been taught that it's the gold standard in thyroid testing.  FT3 correlates best with symptom, FT4 falls behind it, and TSH does not correlate at all.  So, the most alarming number there is your FT4, which is below range.  It can be difficult to find a doctor who will treat FT4 and ignore TSH.

It's the lithium:

http://www.ncbi.nlm.nih.gov/pubmed/9827658

How long have you been on lithium?  The study suggests that the hypothalamus/pituitary/thyroid axis might be "reset" when starting lithium.  
Blank
Avatar_n_tn
Goolara,

Thank you so much for your thoughtful response.

1. Is it pointless to see a doctor until the tsh is out of range?
2. Could the FT4 be responsible for 10-20 lb weight gain?
3. Is there a way to get the FT4 within normal range that does not involve synthroid if they're unlikely to prescribe it with a normal tsh?
4. why is the tsh normal if the FT4 is out of range?  

I've been on lithium for several months but the weight gain problem started before that.  Thank you so much again.  I really appreciate your help.

Blank
Avatar_f_tn
1 - No, it's not pointless.  You just have to pick your doctor.  The good ones know that TSH isn't what it's cracked up to be.  It's best to interview them over the phone before making an appointment.  Ask to speak to a nurse, explain your labs and ask if the doctor is capable of ignoring that TSH and basing treatment on FT4.  You can get some very candid responses.

2 - It's really your FT3 that's responsible for the weight gain.  I know that sounds like a contradiction with FT3 in range and FT4 below range.  Just being in range isn't good enough.  FT3 really belongs in the upper half to upper third of the range.  T4 is made by the thyroid.  It's the "storage" form of the thyroid hormones.  It floats around in your blood stream until cells need thyroid hormone, but before it can be used, T4 is converted to T3, which is the "active" form of the thyroid hormones.  It's T3 that regulates metabolism, and when it's too low, it's very easy to gain weight and next to impossible to take it off.  Because T3 is converted from T4, when all is working correctly, increasing FT4 levels also increases FT3 levels.

3 - That depends on the cause of your hypothyroidism.  For example, hypo can be caused by iodine deficiency.  If that's the cause, obviously there is an OTC "cure" for it.  However, iodine deficiency is rare in this country these days, and Hashimoto's thyroiditis, an autoimmune disease, is now by far the most prevalent cause of hypo.  There are two antibody (blood) tests to diagnose Hashi's, TPOab (thyroid peroxidase antibodies) and TGab (thyroglobulin antibodies).  If you have Hashi's, meds are basically the only way to go.  You might request those tests.

4 - TSH is a pituitary hormone.  Simplified, the pituitary is the master endocrine gland.  It measures FT3 and FT4 levels in the blood, and when they're too low, it secretes some TSH to stimulate the thyroid to produce more hormone.  The hypothalamus is also involved in this process, so the pituitary is at least a few steps removed from the actual thyroid hormones.  TSH can be influenced by a multitude of things...pituitary issues, meds, anything "off" in the thyroid/hypothalamus/pituitary feedback axis.  So, while TSH is usually high when FT3 and/or FT4 are low, and vice versa, that's not always the case.  For example, secondary hypothyroidism is caused by the pituitary not secreting enough TSH to stimulate the thyroid to produce.  So, you end up with FT3, FT4 and TSH all low together.      
Blank
Avatar_n_tn
Goolarra,

Thanks again, truly!!  Your answers are thorough yet so clear.  I will get tested for Hashi's and find a good doc.

Much appreciated.
Blank
Avatar_n_tn
one other question.  Is selenium of any use to increase free T4 or to prevent thyroid from becoming further hypo?  Thanks!!
Blank
Avatar_f_tn
No. Selenium doesn't have anything to do with T4.  However, the enzyme that catalyzes the conversion of T4 to T3 is a selenium based enzyme.  So, a selenium deficiency can impact conversion.

Some people claim that selenium will lower antibodies.  So, it could be something to try if you find you do have Hashi's.  

If you decide to try selenium, be sure to follow label directions.  Selenium is toxic in excess doses.

Another thing I should have mentioned is that if you test positive for TPOab and/or TGab, it will probably be easier to get some treatment.  Elevated antibodies usually make doctors stand up and take notice.
Blank
Avatar_n_tn
Thanks again.  Sorry to bombard you with more questions.

Should i be avoiding foods like cauliflower and nuts?  Will that help prevent further problems?

Blank
Avatar_f_tn
The foods you mention are called goitrogens, which means they can irritate the thyroid and inhibit thyroid hormone production.  Once cooked, these veggies are no problem.  It's only when eaten raw that they will bother your thyroid.  I've never had any problem with any of the goitrogens.

I'm here to be bombarded with questions!  LOL  
Blank
Avatar_n_tn
Are there any specific symptoms pertaining to low free T4 only?  Or do symptoms (constipation, weight gain) only arise when free T3 is low?  Perhaps my symptoms are a result of the TSH and free T3 not being in the optimal range irrespective of my low free T4?  Thank you get again.  Just trying to get to the bottom of everything:)
Blank
Avatar_f_tn
Typically, when FT4 is low, FT3 is going to follow it down before too long.  Obviously, it's not sustainable to keep converting ever lower levels of FT4 to FT3.  

When FT4 levels are low, there's nothing there to convert during times of peak demand.

"Perhaps my symptoms are a result of the TSH and free T3 not being in the optimal range irrespective of my low free T4?"  I'm not exactly sure what you're asking.  TSH causes no symptoms, whether it's zero or in the hundreds.  TSH is nothing but a messenger from the pituitary to the thyroid to tell it to produce hormone.  Your less-than-optimal FT3 is causing your symptoms, but increasing your FT4 levels should also increase your FT3 levels.  My experience is that neither FT3 nor FT4 can be considered to the exclusion of the other.  

Not sure I've answered your question...?    
Blank
Avatar_n_tn
As always, you have indeed answered my question.  Thank you!  I'm going to book a doc's appointment.  I'm assuming best case scenario she/he will subscribe synthroid to compensate for the T4 depletion?
Blank
Avatar_n_tn
Also, I'm reading Mary Shomon's book and I'm wondering how influential nutrition really is on thyroid hormones.  Do nutrition and lifestyle management really help the condition or do the greatest results come from med management?  I'm a vegetarian so reducing soy is rather challenging.  Thank you!
Blank
Avatar_f_tn
Usually, T4 is the first thing tried.  You have to get your FT4 to around 50% of range and watch FT3 to make sure it's tracking it up.  There can be somewhat of a delay in that.  Conversion sometimes has to ramp back up, too.  Once FT4 is at 50% of range, if you are still having symptoms and your FT3 isn't where it should be (50+% of range and higher as a percentage of range than FT4), it's time to think about adding some T3 meds to the mix.

I don't agree with Mary on a lot of things!  As with everything else, a healthy lifestyle and a well balanced diet help you to feel better.  However, when it comes to the gluten free, dairy free, sugar free, FOOD free diets, I don't think they contribute as much as some people would like to believe.  Unfortunately, though, soy is not thyroid-friendly.  

If you have a marginal thyroid condition or are in the very early stages of Hashi's, diet and lifestyle changes might be able to forestall it for a time.  Once your thyroid is ravaged, however, meds management is the only way to go.  Once your thyroid is dead, it actually becomes easier to manage since your thyroid is no longer sputtering and spitting.    
Blank
Avatar_n_tn
Thank you again.  I've learned more from you than any website.

Is T4 a transient number?  Or does it tend to be consistent or worsen with time?  Essentially, is there a chance it will remedy itself without intervention?

Are there any other definite foods besides soy products that should be avoided?

Thanks a million!!
Blank
Avatar_f_tn
FT4 varies some, but on a consistent dosage, it should be fairly constant, unless something else is going on that influences levels or absorption of meds, etc.  Once FT4 is below range, however, I think the chance of spontaneous recovery is probably very small.  Also, thyroid meds don't have to be forever.  Should your FT4 suddenly go up with no change in meds, you can always experiment with decreasing or discontinuing your dose.

In a quick scan, I can't see anything in this thread about antibodies/Hashi's.  Have we talked about that?

As far as food is concerned, I always say listen to your body.  If something causes you distress, don't eat it.  Everything else is fair game.  I don't even have a problem with soy (although I eat very little of it), but I do know lots of people who do.
Blank
Avatar_n_tn
We have not spoken about Hashi's or antibodies.  My sister actually has Hashi's.  Soy does not cause me physical distress but maybe it is causing my FT4 to drop further?  Thank you as always.
Blank
Avatar_f_tn
Well, the jury is still out on the whole soy/thyroid controversy.  As far as I know, there has been no study to determine which compounds in soy affect thyroid hormone production and/or absorption of thyroid meds.  As with everything else thyroid, how it affects the individual is probably highly variable, and which soy products you consume makes a difference.  It could be worth eliminating it in your diet for a while (I have no idea how long it would be before the effects show up in your blood) and retesting before committing to meds.  Since you're a vegetarian, I know that won't be easy, but I don't know any other way to see if it is affecting your thyroid hormones.  

Antibodies:  So, Hashi's is an autoimmune disease and the most prevalent cause of hypo in the parts of the world where iodine deficiency is no longer an issue.  Hashi's also "runs in families", which means a genetic link is suspected, but unproven.  Since your sister has it, the odds are not in your favor.  TPOab (thyroid peroxidase antibodies) and TGab (thyroglobulin antibodies) are the two markers for Hashis.  Only one has to be elevated to confirm Hashi's, but both have to be tested to eliminate it.  It would probably be a really good idea to get those tested so you know what you're dealing with.

It would be interesting to see just how much soy is affecting your FT4 level.  I can't imagine you'd have to eliminate it for very long to see if your level changes when you're not eating it.  It could be well worthwhile to do that and retest and test TPOab and TGab at the same time before you make any decisions.

I've just been reading that as long as iodine levels are adequate, soy should not affect circulating FT4 levels.  However, if you eat a lot of soy (how much?), and you have some esoteric sensitivity to it vis-à-vis your thyroid...you might have to be your own guinea pig.
Blank
Post a Comment
To
Blank
Weight Tracker
Weight Tracker
Start Tracking Now
Thyroid Disorders Community Resources
RSS Expert Activity
748543_tn?1371753642
Blank
TMJ/TMJ The Connection Between Teet...
Jan 27 by Hamidreza Nassery , DMD, FICOI, FAGDBlank
469720_tn?1388149949
Blank
Abdominal Aortic Aneurysm-treatable... Blank
Oct 04 by Lee Kirksey, MDBlank
242532_tn?1269553979
Blank
The 3 Essentials to Ending Emotiona...
Sep 18 by Roger Gould, M.D.Blank
Top Thyroid Answerers
649848_tn?1424570775
Blank
Barb135
FL
Avatar_m_tn
Blank
gimel
MI
Avatar_f_tn
Blank
goolarra
Sisters, OR
657231_tn?1421251398
Blank
rumpled
Northern, NJ
798555_tn?1292791151
Blank
LazyMoose
MN
Avatar_m_tn
Blank
flyingfool
WI