what's my T4 "problem": A blood test Nlovember... - Thyroid UK

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what's my T4 "problem"

GKeith profile image

A blood test Nlovember 4, 2019 showed:

TSH 0.4-4.50 miU/L 0.54L

TT4 4.9-10.5 mcg/dL 3.8L

FT4 0.8-1.8 ng/dL 0.4L

FT3 2.3-4.2 pg/mL 3.4

TT3 76-181 ng/dL 119

Urinalysis was within range

Cholesterol <200 mg/dL 135

Complete Metabolic Panel was all well within range.

I can't figure out why my T4's are low but everything else is good?

Blood test on 1/6/2020 TSH 0.4-4.50 miU/L 0.26L

TT4 4.9-10.5 mcg/dL 5.8mcg/dL

FT4 0.8-1.8 ng/dL 0.8 ng/dL

TT3 76-181 ng/dL 127ng/dL

FT3 2.3-4.2 pg/mL 3.2pg/mL

My T4's are better but still low: My change in dose was from 50 mcg T4 to 75 mcg T4

and 30 mcgT3 to 20 mcg T3 I feel like I need more T3 and so I added 5 more to make it 25 mcg T3. I believe I was under-dosed for 28 years. The GP who started me began at 88mcg T4-only & never changed for 28 years. The last almost 2 years I have gotten an endo and am still tweeking. Any thoughts? I feel really great except for a stiff neck that creaks when I turn it and, occasionally, still, cold hands & feet but then, I'm 74 years old. I know the low T4's mean something, esp. the FT4? Anybody had anything similar?

14 Replies

Your FT4 is low because of the T3 you're taking. That's the way it works: taking T3 lowers the FT4 level. :)

GKeith profile image
GKeith in reply to greygoose

So, is the FT4 converting into T3 because both total & Free T3's are mid-level?

greygoose profile image
greygoose in reply to GKeith

T4 won't be converting any better or any worse than it was before you started the T3. If your T3 is higher it's because you're taking T3.

GKeith profile image
GKeith in reply to greygoose

So, as long as I'm taking T3 my T4 levels are irrelevant? When my endo raised my T4 from 50mcg to 75mcg he did so at my request but refused to raise it unless he lowered the T3 from 30mcg T3 to 20mcg T3. So, I take it that I would have to take T4 only to see if it were converting to T3? My thinking behind all of this is because I took T4-only for 27 years without the original dose of 88 mcg of T4 ever being changed and I have come to the conclusion that if it would have converted and the GP's had raised it I might be on 150-200 mcg T4 right now and feeling just as good as I do now? Very confusing but since I've been taking T3 I can "feel" the difference and feel great on 75 mcg T4 & 20 or 25 mcg T3. The only thing I've haven't tried is NDT, which, I believe more and more they should start patients on the first time they're diagnosed with an under-active thyroid, just to see if it works better for them because I know they give out T4 quicker than T3 because it is so much cheaper and they make more money, which is a red-flag for me; I detest Capitalism and that is America's system but it has failed in every sector, especially Health Care; people die here everyday for lack of money for medications they can't afford. Peace be upon you.

greygoose profile image
greygoose in reply to GKeith

So, as long as I'm taking T3 my T4 levels are irrelevant?

That's not exactly what I said. It isn't important for some people, but for others it is. But, I think it's best to get the FT3 up to a decent level before you start tinkering with the T4. But in any case, it's all trial and error.

When my endo raised my T4 from 50mcg to 75mcg he did so at my request but refused to raise it unless he lowered the T3 from 30mcg T3 to 20mcg T3.

That was very wrong of him without a lot more information. I think it just goes to show he doesn't know much about dosing.

So, I take it that I would have to take T4 only to see if it were converting to T3?

That is true. You cannot see how well you convert without being on T4 only. Which is why your endo was wrong to reduce blindly your T3 the way he did.

My thinking behind all of this is because I took T4-only for 27 years without the original dose of 88 mcg of T4 ever being changed and I have come to the conclusion that if it would have converted and the GP's had raised it I might be on 150-200 mcg T4 right now and feeling just as good as I do now?

Totally impossible to come to that conclusion. Far to many unknowns and variable. Nothing with hormones goes in a straight line. You would have to try it and see.

Very confusing

Only because you're rushing at hurdles without seeing what's on the other side. :) You have to take things one step at a time.

since I've been taking T3 I can "feel" the difference and feel great on 75 mcg T4 & 20 or 25 mcg T3.

Then that's what you should take, and stop worrying about what might have been.

The only thing I've haven't tried is NDT

Might not suit you. If you're happy on what you're taking then why take the risk? And the T4:T3 ratio is not the same. 1 grains of NDT has 68 mcg T4 and only 9 mcg T3, so there might not be enough T3 for you. My motto is: if it ain't broke, don't fix it.

The only thing I've haven't tried is NDT, which, I believe more and more they should start patients on the first time they're diagnosed with an under-active thyroid

Problem is, NDT doesn't suit everyone. I dread to think where I'd be now if I'd been started on NDT right from the beginning.

just to see if it works better for them

But how would they know it works better for them if they've never tried anything else?

I know they give out T4 quicker than T3 because it is so much cheaper and they make more money

It's not just that. It's also that they only learn about T4 in med school and are totally out of their depth with T3 or NDT. They like to stay in their comfort zone.

GKeith profile image
GKeith in reply to greygoose

Thanks for the knowledge, again. Peace be with you.

greygoose profile image
greygoose in reply to GKeith

And with you. :)

SlowDragon profile image
SlowDragonAdministrator

Many people find they need good levels of both FT4 and FT3

It's trial and error what suits each individual

GKeith profile image
GKeith in reply to SlowDragon

What's you idea of good levels? I take it to mean halfway to upper levels? That's why I asked about the T4's, which are higher now than 3 months ago but still low. I think I will add another 5 mcg T3 but I'm not so sure about the T4's?

Lora7again profile image
Lora7again in reply to GKeith

Some people need their T4 and T3 to be in the upper third of the range or higher to feel well. We are all different.

GKeith profile image
GKeith in reply to Lora7again

Since greygoose answered it appears that I have no say over how high or low my T4 will be and there's no way I can control it, as long as I'm taking T3 with it. May Peace be upon you.

SlowDragon profile image
SlowDragonAdministrator in reply to GKeith

You could try 25mcg increase in Levothyroxine first. This should also improve FT3 a little

Never increase both...only one or the other and test 6-8 weeks after dose increase

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .

Last dose of Levothyroxine 24 hours prior to blood 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 5mcg dose 8-12 hours prior to test, even if this means adjusting time of splitting dose day before test

Are your vitamin levels optimal?

You need vitamin D, folate, B12 and ferritin tested at least annually. More frequently if you supplement

GKeith profile image
GKeith in reply to SlowDragon

T4 won't be converting any better or any worse than it was before you started the T3. If your T3 is higher it's because you're taking T3. This is greygoose's answer above and, so far, I've never been able to prove her wrong.

SlowDragon profile image
SlowDragonAdministrator in reply to GKeith

Actually many of us find we need to slowly increase Levothyroxine dose back up after starting on T3

You were never on high enough dose of Levothyroxine before T3 was added. Most people need somewhere between 100mcg and 200mcg Levothyroxine. So to have reduced 88mcg down to 50mcg was always going to result in extremely low FT4

Your FT4 and TT4 remain very low

Every person is an individual

Many of us need good Ft4 and good FT3 levels

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