Free T3 went to minus, is very low: Hi, my last... - Thyroid UK

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Free T3 went to minus, is very low

Eliara2 profile image
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my last thyroid lab values shows that my free T3 is in minus, it never was. I have no thyroid since 2009. I take Levo 125mcg

TSH: 2.8

Free FT3: -15%

Free FT4: 40%

A year ago I got reflux, so went on low carb high fat diet, which helps to my reflux. Maybe bcs of high fat my Free T3 is low now?

My previous lab test were with Levo 125mcg ~ 5 months back:

TSH: 0.4

Free FT3: 55%

Free FT4: 42%

And additionally to this, one week I have head pain or like a pressure, behind right side.

So scary. Thanks!

1 Reply
SlowDragon profile image

Previous posts say you were on higher dose of 175mcg before trying NDT

TSH of 2.5 is too high for someone on Levothyroxine. You need 25mcg dose increase and retesting in 6-8 weeks

For full Thyroid evaluation you need TSH, FT4 and FT3 tested. Also extremely important to test vitamin D, folate, ferritin and B12

Low vitamin levels are extremely common, especially if Thyroid antibodies are raised

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and fasting. Last Levothyroxine dose should be 24 hours prior to test, (taking delayed dose immediately after blood draw). This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)

If/when also on T3, make sure to take last dose 8-12 hours prior to test

Is this how you do your tests?

Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or antibodies or all vitamins

Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have special offers, Medichecks usually have offers on Thursdays, Blue Horizon its more random

List of hypothyroid symptoms

Dr Toft, past president of the British Thyroid Association and leading endocrinologist, states in Pulse Magazine,

"The appropriate dose of levothyroxine is that which restores euthyroidism and serum TSH to the lower part of the reference range - 0.2-0.5mU/l.

In this case, free thyroxine is likely to be in the upper part of its reference range or even slightly elevated – 18-22pmol/l. Most patients will feel well in that circumstance.

But some need a higher dose of levothyroxine to suppress serum TSH and then the serum-free T4 concentration will be elevated at around 24-28pmol/l.

This 'exogenous subclinical hyperthyroidism' is not dangerous as long as serum T3 is unequivocally normal – that is, serum total around T3 1.7nmol/l (reference range 1.0-2.2nmol/l)."

You can obtain a copy of the articles from Thyroid UK email print it and highlight question 6 to show your doctor

 please email Dionne at

Professor Toft recent article saying, T3 may be necessary for many especially after thyroidectomy or RAI

Getting TSH down to around one and FT4 in top third of range is first step

All four vitamins need to be optimal

If FT3 remains low then you may benefit from the addition of small dose of T3

Email Dionne at Thyroid Uk for list of recommended thyroid specialists who will prescribe T3

please email Dionne at

New NHS England Liothyronine guidelines November 2018 clearly state on pages 8 & 12 that TSH should be between 0.4-1.5 when treated with just Levothyroxine

Note that it says test should be in morning BEFORE taking Levothyroxine

Also to test vitamin D, folate, B12 and ferritin

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