80/20 T4 and t3

[klaea]

Read that the healthy thyroid produce 80t4 and 20t3 and therefore Westin Child's try to give that amount to his patients. Do you find this to be best also? Or what percentage are you taking?

[TiggerMe]

If only it were that simple, truth is everyone is different so fine tuning your personal dose is essential

I think this is an over simplified statement made by a Dr that has a one size fits all attitude 😕

Surely if he treats many people he would know this isn't the case?

[Buddy195 Administrator]

We all have different ‘sweet spots’ where we feel most well. I find it useful to adjust medication super slowly (eg adding or reducing 12.5mcg Levo alternate days at first until well tolerated). I never adjust Lio and Levo at the same time. With Liothyronine I adjust by 2.5mcg daily. I’ve found this slow approach means I can find an optimal dose for me. It’s always a good idea to retest thyroid levels 6-8 weeks after being on a consistent dose.

[jimh111]

Not true, the thyroid secretes about 90 mcg T4 and 6 mcg T3 daily. About 80% T3 comes from peripheral conversion of T4 and 20% from the thyroid.

[pennyannie]

Hello Klaea :

Working on a 1/4 ratio T3/T4 is a ball park figure -

if you look at most ranges - the T3 base line is around a quarter of the T4 base line -

at around 1/4 - T3/T4 ratio and on a sliding scale - eg -

Medichecks ranges have the T3 range at 3,10 - 6.80 with the T4 range at 12 - 22.00

with the presumption being that the T3 reading builds up at a percentage of the T4 reading :

In practise we know this does work as once taking T4 it tends to lower one's own natural production of T3 anyway.

The most full spectrum of all thyroid hormone replacements and the original successfully used treatment for over 100 years is NDT - which is derived from pig thyroids, dried and ground down into tablets referred to as grains - and with a stated fixed ratio of 1/4.22 - T3/T4 :

This ratio suits many thousands of patients - though some need a small adjustment of either a little synthetic T3 or T4 alongside their main dose of NDT to fine tune to their unique set point where they feel better .

Down regulation of T4 into T3 can be caused by low levels of core strength vitamins and minerals, any chronic long term health issue, inflammation, antibodies, any physiological stress ( emotional or physical ) depression, dieting and ageing -

So one's own personal T3/T4 ratio may not be exactly a 1/4 ratio - T3/T4 - but a guide as to where one might start to feel some relief of symptoms of hypothyroidism.

I also read that the accepted conversion ratio when taking T4 monotherapy is 1 / 3.50 - 4.50 T3/T4 with most of us feeling at our best when we come on this ratio at 4 or under.

I also read that synthetic T3 - Liothyronine is said to be around 3-4 times more powerful than synthetic T4 - Levothyroxine - and since we do not all absorb and convert these hormones the same way - its not just a mathematical equation - but a very individual case of treating patients as individuals and finding each persons unique set point which is likely somewhere in the T3 and T4 ranges :

I read that a fully functioning working thyroid would support one on a daily basis with trace elements of T1. T2 and calcitonin + a measure of T3 at around 10 mcg + a measure of T4 at around 100 mcg

[helvella Administrator Thyroid UK in reply to pennyannie]

Trouble is, grams or moles of hormone per litre in the bloodstream (scaled with milli, micro, nano and pico as needed!) is very much different to amount produced or taken.

The amounts of thyroid hormones on the bloodstream are the result of additive and subtractive processes: They are the instantaneous balance point of all these processes.

Additive including secretion/release, conversion, and exogenous sources, and (for free tests) the release of thyroid hormones from bound states to free

Subtractive including excretion, conversion (T4 to T3, rT3, and T3 to T2), conjugation (sulphation and glucoronidation), other processes that affect the thyroid hormones themselves including binding to blood proteins (assuming free tests are being discussed).

Therefore, you cannot take blood tests (ranges or results) as an indicator of T4:T3 ratios - other than specifically what is in the blood.

[helvella Administrator Thyroid UK]

Which is nonsensical.

Start with:

Absorption of T4 is typically reported as being something like 60 to 80%. Whereas absorption of T3 is reported as being often over 80% and frequently close to 100%.

So first step would be adjusting the ratio in the doses to account for that. But we do not know how much of either an individual taking them absorbs. We'd be using statistical means (or whatever) of the populations who have been researched - which might or might not align with the individual.

Then:

Absorption of T4 (in particular) is well known to vary by product. For example, one make might be sufficiently better absorbed than another for it to make a clear impact on thyroid hormone levels.

Then:

Consider the meaning of "produces". The healthy thyroid produces T3 directly but ALSO converts some T4 into T3. Which makes the assertion somewhat more complex.

Then:

80% and 20% of what? Does he know how much thyroid hormone the person he is treating produced when well? Again, back to applying general population statistics to the treatment of any individual.

Then:

Someone who does not have a healthy thyroid is not the same as someone who has a healthy thyroid. Whether the change occurred in a few seconds due to an operation, weeks due to RAI, years due to autoimmune processes, or the person was born without a thyroid. Taking thyroid hormone is very different to having it delivered by a healthy thyroid under proper biological control.

No-one knows enough to assert that someone born without a thyroid requires an 80:20 ratio - quite possibly not one single person has ever been given a combination therapy from birth. (Other than some who got desiccated thyroid which is close to that.)

Then:

If you took 100 micrograms of T4 and converted it, perfectly, to T3, you would end up with 84 micrograms of T3. Chemists and bio-scientists often look at molecular activity based on numbers of molecules (molar quantities) rather than weights (masses).

I strongly suspect that 80:20 is based on masses rather than molar quantities. But you can be absolutely certain that most of those who discuss these issues fail to notice this difference.

(Added for clarification)

Thyroid tests with results in pmol or nmol, etc., are molar measurements. Those in nanograms or picograms are mass measurements. You cannot possibly make progress without being absolutely clear in every statement at every step of the argument/explanation which you are dealing with and managing conversions properly.

Finally:

80:20 by weight might, sometimes, be appropriate. But don't let anyone claim that it is universally applicable. Nor that they have any scientific basis to apply it to an individual. It is, at best, a guess. Which might be all they can do - but I wish they'd be honest. They could say, "I have 100 patients taking 80:20 and doing well - and blood tests also look good. So that seems a reasonable dose to aim towards. But we might well find you need a higher or lower ratio and will adjust as needed by YOU and YOUR BODY."

[jgelliss in reply to helvella]

This was a very informative post. Thank You.In my experience after my TT I was dosed with very high doses of T4 . At first it felt well. But with time many side affects started palpitations anxiety insomnia etc. Lowering the T4 had it's own side effects. No energy just couldn't function . Adding T3 to my T4 dose made a world of a difference for me. I feel that perhaps not having my own G-D given thyroids sets me up to perhaps needing more thyroid hormones than my own thyroids made. And for myself as well I don't fall into the ranges that the labs have. On the labs I'm over and for me that works well. If I would follow the ranges it would make me feel very unwell. With my thyroid journey I learned that lab ranges don't work for me and one size fitts all at least as thyroid meds are concerned does not work for me either.

Trusting how I feel is very crucial over labs for me. I don't convert my T4 to T3 well. Since they don't have the know how to test cellular. I will go by how I feel.

[tattybogle]

The variation between healthy individuals is actually quite large . much of the information used , and often repeated without question comes from a study of just 14 people done in 1990 :

some reading that may interest you :

thyroidpatients.ca/2019/06/... question-pilos-study-the-wide-range-of-thyroid-hormone-adaptation/

thyroidpatients.ca/2019/05/... question-pilos-1990-study-it-can-be-misused-to-limit-your-t3-supply/

thyroidpatients.ca/2020/08/... Meet a person with the perfect T3:T4 thyroid secretion ratio