Low fT4, but midrange fT3. Feeling cold, brain fog.

[gd33]

Hi there,

male, 64, fit, no problems besides this: for about 3 years I´m having symptoms like feeling cold, brain fog, and most things one would consider to be low thyroid function.

I did a lot of blood tests in the last year. Most values are ok.

Zinc, Vit B, Selen etc. has all been tested ok, too.

The problem IMHO seems to be that fT4 is always at the bottom of reference, while fT3 is always in the mid range. TSH is normal.

This test has been repeated some times, and comes back always this way.

I read that fT4 low and fT3 midrange could mean to be iodine deficient.

Currently, I do not take any Thyroxine, and have not before.

Which way should I go? Take iodine, take T4 or T4/T3, a combination of these, or something different?

Any ideas are welcome.

[SlowDragon Administrator]

Please add actual results and ranges

Have you tested thyroid antibodies

For full Thyroid evaluation you need TSH, FT4 and FT3 tested

Also both TPO and TG thyroid antibodies tested at least once

Very important to test vitamin D, folate, ferritin and B12 at least once year minimum

About 90% of primary hypothyroidism is autoimmune thyroid disease, usually diagnosed by high thyroid antibodies

Autoimmune thyroid disease with goitre is Hashimoto’s

Autoimmune thyroid disease without goitre is Ord’s thyroiditis.

Both are autoimmune and generally called Hashimoto’s.

Low vitamin levels are extremely common when hypothyroid, especially with autoimmune thyroid disease

Low vitamin levels also more common as we get older

please add actual vitamin results and ranges

20% of autoimmune thyroid patients never have high thyroid antibodies and ultrasound scan of thyroid can get diagnosis

In U.K. medics hardly ever refer to autoimmune thyroid disease as Hashimoto’s (or Ord’s thyroiditis)

Recommended that all thyroid blood tests early morning, ideally just before 9am, only drink water between waking and test

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)

Private tests are available as NHS currently rarely tests Ft3 or all relevant vitamins

Testing options and includes money off codes for private testing

thyroiduk.org/testing/

Medichecks Thyroid plus antibodies and vitamins

medichecks.com/products/adv...

Blue Horizon Thyroid Premium Gold includes antibodies, cortisol and vitamins

bluehorizonbloodtests.co.uk...

Only do private testing early Monday or Tuesday morning.

Link about thyroid blood tests

thyroiduk.org/testing/thyro...

Link about Hashimoto’s

thyroiduk.org/hypothyroid-b...

Symptoms of hypothyroidism

thyroiduk.org/signs-and-sym...

Tips on how to do DIY finger prick test

See detailed reply by SeasideSusie

healthunlocked.com/thyroidu...

Medichecks and BH also offer private blood draw at clinic near you, or private nurse to your own home…..for an extra fee

[gd33 in reply to SlowDragon]

Thyroid has been tested last year with sonography. Size is normal, no antibodies, no problems found.

Blood check from 09/2023:

TSH 1.11 (0.30 - 4.00)

fT3 4.17 (2.43 - 6.00)

fT4 10.6 (9.10 - 19.00)

Also check of Vit D and ferritin was ok. I take the usual supps, the blood checks always come back as normal.

The only out of range have been these two:

gamma globuline 10.6 (11.1 - 18.1) in %

pregnenolon 18.9 ( 24.0 - 60.0) in ug/l

[SlowDragon Administrator in reply to gd33]

What are your actual results and ranges for vitamin D, folate , B12 and ferritin

[SlowDragon Administrator in reply to gd33]

ameripharmaspecialty.com/ga....

Low gamma globulin levels mean that your body cannot produce enough antibodies and that you need to be evaluated by an immunologist, who may indicate replacement therapy to avoid infections.

levitasclinic.com/pregnenol....

When pregnenolone levels are low, your body can not create enough other hormones, causing hormonal imbalances which can affect your daily functioning. The symptoms of low pregnenolone include poor memory, declining concentration and attention, fatigue, dry skin, joint and muscle pain and decreased sex drive.

drlamcoaching.com/blog/how-...

[greygoose]

I read that fT4 low and fT3 midrange could mean to be iodine deficient.

That is true, but it's not that simple, it could also mean other things. So, whatever you do, don't take iodine unless you have been tested for it, and been found deficient, AND you are supervised by an experienced practicioner. There are protocols to be set up, it's not as simple as just taking a pill.

So, your next step should be to get your iodine tested, if you think it might be that. A non-loading urine test is best, I believe.

[Shakeyjakeblues]

It could be a pituitary gland issue. Secondary Hypothyroidism is where the pituitary gland can't release enough TSH to stimulate a healthy thyroid. At diagnosis FT4 is low and TSH either low or normal range, when it really should be high. The treatment is the same as primary hypothyroidism but TSH can't be used to guide dosage. It's often caused by a cyst or benign tumor on the pituitary gland. It's very rare that they are cancerous and are usually slow growing. Normally if one is suspected you'll have blood test to check the pituitary hormones, some are indirectly tested, plus an MRI with contrast.

[Bearo]

Secondary hypothyroidism sometimes comes under the heading of Central hypothyroidism.

GP probably won’t have heard of it . If they have they’ll tell you it’s very rare and therefore won’t test for it! You should be referred to an endo if it is suspected. Endo might refuse to see you because your results are in range.

[gd33]

@Slow Dragon:

Vit D 77.2 (30 - 59)

Ferritin 102 ( 30 -400)

Folate was not checked, did´t know it should be

No checks for B12, I take a Vit B complex with B12

[gd33]

I did another blood check, the results: fT3 4.23 (2.43-6.00) and fT4 12.7 (9.10-19.1).

So I guess it´s not the thyroid. I will look into other things and report later.