If T4 has to be converted to T3 before it can be used...

[Rhub4rb]

why don't all doctors (assuming it doesn't cost a fortune) just prescribe T3 as surely it will work when T4 doesn't always? Why do people take a mixture of T4 and T3?

[helvella Administrator Thyroid UK]

Several reasons.

Start with cost. In the UK, around £204 for 28 T3 tablets against £1 or £2 for T4.

Then the fact that many people feel the need for T4 even if taking mostly T4.

And that taking T3 tends to rise to a peak and then fall away much faster than T4.

Then ask why, if all we need is T3, the healthy body produces mostly T4.

And consider that the brain, in particular, performs much of its own conversion of T4 to T3.

And that doctors and labs together almost always fail to request and perform any T3 blood tests.

I am always amazed that some people seem to do so well on T3 only! It always strikes me that T3-only is as non-physiologic a treatment as T4-only.

[diogenes Remembering]

T3 is a very quick acting hormone with a half-lifetime of only 1 day. T4 on the other hand has a half-life of a week or more. The body produces a big reservoir of T4 to act as a non-reactive "buffer" control. That is, there is a big excess of already made T4 which can be converted to active T3 as the body cells want it. Imagine if T4 was only made and stored at just the level needed for cell use immediately - there would be no smoothing out of the T3 requirements because there would be no excess of T4 as the "larder" of storage. This would be very unstable for the body's health and a continued strain on the thyroid gland. Secondly if only T3 was made to order from the thyroid this too would be unstable for fluctuating body health. We must remember that "health" is not a static ideal - healthy (so-called) people vary all the time in the degree of health they have and the thyroid must respond minute by minute to address any changes needed. Better to use a stored excess of the inactive T4 as a source of T3, because this is instantly recognised by the body cells and furthermore can continue to act unchanged even if the thyroid is temporarily compromised .

[Naomi8 in reply to diogenes]

What is your opinion of the impact of the D102 SNP on this process when inherited from one parent & both parents

[diogenes Remembering in reply to Naomi8]

None in health. The body's mechanisms have adapted. But in thyroid loss, obviously the mutations in the conversion genes mean that different treatment has to be done compared with patients with normal genetic expression. The former may ned T3 as well as T4, and the latter are more likely to get along OK with T4 only.

[Naomi8 in reply to diogenes]

Just to clarify,if thyroid gland is present but failing(as in Hashi's)the SNP has an effect.Did you mean the reverse of what you wrote inheriting the D102 SNP

ie SNP from one parent,T3 probably not needed.SNP from 2 parents,T3 needed

[diogenes Remembering in reply to Naomi8]

It all depends on the exact expression of each gene. The wild type may predominate over the mutation or it may be the other way round. No what I said was that DIO2 mutant people may need T3, but others probably could use T4 only.

[Naomi8 in reply to diogenes]

thanks for clarifying

[Harthill42 in reply to diogenes]

T3 is a very quick acting hormone with a half - lifetime of only one day.

Why on my last endocrinologist visit on the 20th of February did he say stop taking my 12.5 per day of T3 as it wants to re test me in 8weeks as it then shall be out of my system to see if I am conveying from T4?

[diogenes Remembering in reply to Harthill42]

The T3 you have taken will be well out of your system in a week. Any T3 left after that is the T3 you are making from T4. Yur ability to convert can't be measured until the T3 taken orally has gone.

[Harthill42 in reply to diogenes]

Thank you. I still don’t understand why he wants me to stop taking it for 8 weeks then test!! It going to make me go backwards, I couldn’t cope with working full time & a demanding job just on the 75mcg of T4 alone. Or is it really me feeling the placebo affect.

[diogenes Remembering in reply to Harthill42]

In your case I think it is rather reprehensible to treat you as an experimental animal. To do something that is going to test and decrease your health unnecessarily is not ethical in my opinion

[DippyDame in reply to Harthill42]

Has he never heard, "first do no harm"!

I'm not a medic but that is rediculous!

Pity he didn't think of testing before prescribing T3.

Do you have your diagnostic test results (before levo and T3)? High FT4 and low FT3 would have suggested poor conversion. You are legally entitled to request copies.

According to V Panicker et al (2009) the DIO2 snp inherited from both parents indicates worse conversion than if from one parent. In either case combination therapy may, and often does, help.

I am DIO2 homozygous and take 100mcg T3 in a single dose but I suspect that has more to do with thyroid hormone resistance than the DIO2snp, - otherwise I would be vastly/dangerously overmedicated!

You need a new doctor, one who actually understands thyroid testing/treatment. Is that possible?

Good luck

DD

[Harthill42 in reply to DippyDame]

Thanks for the good advice. I hadn’t thought about requesting the results before I started on Levothyroxine in November 2017.

Looking back I must have been hypothyroid for many years struggling unnecessarily.

[RockyPath in reply to Harthill42]

My endocrinologist and his practice nurses are all stuck in the LT4 treatment mindset, which works on a six-week timeframe to observe metabolic changes. Since moving to T3, I have had to instruct them in the necessity of thinking in smaller units of time, and they have done so.

I suggest you remind them that the exogenous T3 will be gone in the blink of an eye and then advise them that you will not suspend dosing yourself until there is an appointment for blood tests within a very short period of time, after which time you will resume dosing yourself with the LT3. And that you will be happy to sit down and talk about it at the next appointment, in whatever month they've scheduled it.

[Harthill42 in reply to RockyPath]

Thank you, that makes so much sense

[MaisieGray]

In addition to the comprehensive points made by helvella, I don't think there is evidence that T4/Levothyroxine "doesn't work". It's certainly the case that different people, for whatever reason, convert T4 - whether endogenously or exogenously obtained - to T3 less or more efficiently; but that's different from saying T4 doesn't work, and there can be very different reasons for poor conversion. In any case, there are far more happy healthy people in the real world taking Levothyroxine without a problem, than are posting in fora because they aren't; we can't/mustn't extrapolate from what is reported in groups such as this, that no one does well on Levothyroxine, nor indeed, anything else. Equally there are those taking mono-T3, or even combination T4/T3, that aren't happy and well either, in the same way that not everyone does well with Levo or NDTs. Regarding price, at its peak price in the UK, liothyronine was costing the NHS c£258 per 28 tablets of 20 mcg. It's often said in the mono-T3 support group that follows Paul Robinson's protocol, that people take on average, 60 mcg daily, although of course some will take more and some less. So as a for instance, at its peak cost when de-prescribing began to take effect in earnest, that dose would have cost the NHS approx £774 per 4 wkly. Compare that with someone taking say, 125 mcg T4, the cost to the NHS would have been very approx £2.50 per 4 weekly - absolutely no comparison. Even with the price of T3 having come down, it is still in excess of £200 per 28 x 20 mcg tablets compared with say, 0.97 pence for 28 X 100 mcg tablets of T4. But in any case, we are each individual in our health circumstance, and even in how we metabolise/process the drugs we ingest, so we need more options rather than fewer.

[Hidden in reply to MaisieGray]

The following Transcript of the talk by Dr John Midgley at the Thyroid UK 2014 Conference 18/10/2014 History of Thyroid Testing provides an excellent insight into the subject of thyroid testing.

2 other papers provide further developments:-

Thyroid hormone replacement –a counterblast to guidelines

by AD Toft

and

Variation in the biochemical response to L-thyroxine therapy and relationship with peripheral thyroid hormone conversion efficiency

John E M Midgley, Rolf Larisch1, Johannes W Dietrich2,3 and Rudolf Hoermann1

For a real perspective into Liothyronine pricing:-

CAS 55-06-1 Liothyronine sodium Chemical World Report

researchandmarkets.com/repo...

[Rhub4rb in reply to Hidden]

Thank you.. in particular I found the counterblast to guidelines very interesting!

[DippyDame]

You might find this very interesting!

Thanks to shaws for posting earlier - hope you don't me doing a c&p for Rhub4rb

drmalcolmkendrick.org/2015/...

[Naomi8 in reply to DippyDame]

Thanks for posting this link-he describes exactly how I was treated by my new GP on Friday,despite my success with NHS T3 followed by BYO NDT & T3 over a 5 year period,it was "go back to thyoxine because I say so"The only regret I have at my relocation is having to leave my lovely female GP,who treated me with respect,interest & friendliness.She trusted me to get on with my own medication & was there when I needed help.

[DippyDame in reply to Naomi8]

I sympathise, what a prat!

My lovely GP moved away a few months ago. She was unable to either test or prescribe T3 but understood my reasons for self medicating and trusted me to do so. I kept her updated and we had a great working relationship.

I suspect the others in the practice think I travel by broomstick....hope they don't see my TUK avatar!

Just doing my own thing now although I asked to see an endo because I want him to record my clinical need for T3 on my med records......just in case I fall off that broomstick and end up in hospital! I told him I hadn't come to ask for T3 because I buy my own.

Surprisingly he listened to all I had to say (including DIO2/homozygous and thyroid hormone resistance) didn't freak out at my 100mcg T3 single dose and said "I need to do some research before I can comment further, I'm not dismissing what you say". All fine until

I read in yesterday's local paper that he is retiring later in the year....sod's law, he seemed like one of the good ones!

Enough about me....sorry, I'm ranting again!

I really hope things improve for you, if not, don't be pushed into a situation you know won't work for you. Take control and do as many of us here do.....read, learn and self medicate. I would never have considered any of this were it not for the courage and advice fellow members gave me.

Best of luck

DD

[Naomi8 in reply to DippyDame]

At the moment,I am "going away & thinking about it",as instructed by the old fart.

I am intending to pay for a private consultation with an endo on TUK's list.This GP said he was willing to work with a private endo,as long as it was the one he specified.I'm not risking my money on that,given this GP's attitude.I have done the D102 genetic test & have been prescribed T3 on the NHS until it was withdrawn,after which I paid for my own & took 55mcgs daily for 2 years.I am happy to pay for my own again & trial thyroxine with T3.I cannot raise my NDT,as my TSH will go too low (below 0.005)& my T3 will go over-range again & yet I have gone from 20 years at size 16 to an 18.So I am ready to try the combo.

I am hoping this will work for me & he will agree to me being on T4 with T3.Over the next few months,the practice is amalgamating with a bigger,apparently better practice(these are the only 2 in my catchment area)so I am going to hang on!But not at the expense of my health going backwards.

My genetic test showed I do not clear cortisol effectively & a previous test showed MTHFR.This explains my 2 crack-ups-one on T4-only,one on T3-only.

As NDT hasn't been great for my weight or energy,I am hoping this way forward will be a compromise that will be acceptable to all future GPs,even this one,who's mind is so closed.

[jgelliss]

It's actually Very Simple . It's called GREED . It all boils down to M-O-N-E-Y . It's as simple as that . It doesn't get any simpler . BIG PHARMA has their hands in the MEDICAL ACADEMIA'S and Dr's POCKETS . If T4 doesn't work and they know it doesn't in many instances . They are assured that Dr's will take out their script pads and write a script for sleeping pills if that doesn't work will then try maybe BP pills , Oh even better some tranquilizers pills and so on . Dr's hands are tide in many ways . You might find a Dr that is caring knowledgeable and works with a heart and ***LISTENS*** and *GETS IT* . But how many are there ???