T3 levels in normal people.

[krisneptune]

Hello everyone, I have a question. From my new found knowledge about the thyroid hormones, it looks to me that the important measure is amount of Free T3, this is the one that goes into receptors in each cell of the body and gets all sorts of processes going, if you do not have enough then things do not go well. So people who have working thyroid glands have enough T3 around, but does their level in the blood go up and down according to what is happening, if it a cold day, does the level go up? Are there any times when it would go down, or does the level stay the same. If the former then does this mean, if you have hypothyroidism, that you will not have a flexible T3 level from taking thyroid hormones. And calcitonin does not seem to be important, is there a preparation to take for this.

[SeasideSusie Remembering]

krisneptune

Levels are not static, they change throughout the day.

You might find the following post by helvella interesting. It is a graph of the daily rhythm of thyroid hormones - TSH, FT4 and FT3. Remember that reference intervals vary from lab to lab, the ranges used in that study may not be the same as the range your lab uses. The study was performed using healthy individuals:

healthunlocked.com/thyroidu...

I can't comment on calcitonin, it's not something I have looked into. As far as I know it is involved in regulating calcium in the blood. Here is one article, I haven't studied it:

yourhormones.info/hormones/...

[krisneptune in reply to SeasideSusie]

Hi SeasideSusie, have just read helvella post, very interesting, just what i was looking for. There is a diurnal rhythm wit all 3, so time of day for a blood test is important, and should be kept consistant if possible. Thanks, chris

[helvella Administrator Thyroid UK]

My view has always been that the body attempts to maintain a steady level of T3.

The amount of T3 required to achieve this might well vary depending on exercise, temperature, etc. But the blood level tends to be pretty static.

It might be that if we suddenly went from summer to winter weather, it would take a while to increase T3 production. Therefore T3 levels might take a while to be restored. (When I have travelled between hot and cold countries, it always seemed to take towards a fortnight to acclimatise. Could it be that is how long it takes to adjust T3 production? Had no understanding whatsoever of thyroid at the time.)

One of the reasons T3 testing is dismissed by many doctors is the view that it goes up and down all the time. Wrong-headed and not backed up by proper testing and observation.

Of the three thyroid tests, TSH definitely changes far more, and more quickly, than T4 or T3. Yet doctors are fixated on TSH measuring and virtually never take any account of the variations that occur.

It appears that calcitonin is routinely dismissed. It does appear to be of little relevance in humans but dismissing it entirely might be going too far.

When calcitonin has been used as a medicine there have been issues with delivering it (it gets destroyed by stomach enzymes) and evidence which suggests it can cause cancer. Nasal sprays have been used.

Desiccated thyroid products might contain some calcitonin but whether any can get into our bloodstreams is questionable. And porcine or bovine calcitonin is at least slightly different to human calcitonin.

[krisneptune in reply to helvella]

Hi helvella, have just read your other post with the graphs on too, very interesting. This is getting complicated, have not been able to fully understand adrenal fatigue yet!Thanks for the reply, cheers Chris

[jimh111]

T3 can vary a bit from day to day. T3 can fall a lot in severe illness or trauma, it seems to be a protective mechanism although it is poorly understood.

[krisneptune in reply to jimh111]

Hi jimh111 thanks for the reply, it is very complicated. Cheers Chris