Thyroid UK
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Morning all. I hope you had a good weekend.

I've a question for you (again) please.

Is there roughly a 'average' amount of T4 Levothyroxine that people take?

I know everyone is different and we are all on different levels but does it kinda weigh out so there's a average?

I'm now on 125mg I am just curious if this is low, average or high.

I've only been on this dose for one week so looking forward to the 'wellness' I'm hoping it will bring.


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Actually, this question could be split into two questions a) how much do people need on average and b) how much are doctors willing to prescribe on average. And the two are not necessarily the same.

Just because people take a certain dose, prescribed by their doctors, it does not mean that that is the dose they need. Those that can persuade there doctors to prescribe a high enough dose to make them euthyroid, are often on a much higher dose than those whose doctors won't budge!

Doctors like to prescribe a minimum they can get away with. I don't think they understand the difference between a hormone and a drug. And they often like to prescribe enough to get the TSH just into range, and that's it, they won't go any higher, whereas to be euthyroid, you usually need your TSH at the bottom of the range, if not suppressed.

I don't know what is the average for either of these questions, but when looking at pie charts and things, it's important to know which question they're answering.

For myself, I got up to 200 mcg levo, and my TSH was still at 9.5! And my doctor said, well, you can't increase your dose anymore! I asked why, and he said, because they don't make any larger pills, 200 is the maximum!!!!!!!! Which is when I knew I had to find a doctor with a brain! Of course, my problem was that I just couldn't convert that levo into T3, but he didn't know what T3 was!

So, all that to say that what you're asking is a multi-faceted question, and the easy answer might not be any answer at all! Do you know how well you're converting? :)


Hi greygoose ,

Thanx for explaining. It's all so mind boggling. I assume if I am actually converting I would be able to loose weight and I would have some kind of libido?? Neither apply. My latest results are following and my Endo put me up to 125. She said I could go up to 175/200 but I think she thinks I'm going to be ok on 125.

TSH 2.179 (0.400-3.100)

T3 (ft3) 3.2 (2.6-5.7)

T4 (ft4) 13.8 (9.0-19.0)

She said she wants my TSH at zero and my t3 and t4 at the top of the ranges.

I see her again at the end of January.

I'm also on 80mg of iron a day which I take with the 1000mg of vitc.


Well she sounds pretty good for aiming for a low tsh but why is your tsh over 2 right now? I don't know that I see a conversion issue but you're deffo undermedicated (which can make you feel awful) on the dose reflected in the results above. May I ask what your dose has been raised from? If this is your result on 100 for example, you will likely need more than an extra 25mcg.

When you're on a good dose - one that raises your t3/t4 and gets your tsh down to under 1 - you may begin to feel better but it can be a fine balancing act between meds and nutrition. Your libido may come back on a better meds regimen but if it doesn't you can test sex hormones and see if that tells you more.

I was converting just fine but was very bloated until I added in a small amount of t3 to my levo. I have no idea why converting from levo didn't sort that out but if I don't take my t3 all the swelling comes back. Do you think you have gained body fat or is it fluid?

Btw I am on alternating 100/50 levo and 10 t3. Am about to do another test as I wonder if my meds need a little bump up.

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Well, she sounds very clued up, and that's great! Good find, there! It's very rare to find an endo that isn't scared stiff of a suppressed TSH! Cling on to her for dear life! :)

You seem to be converting ok, but you don't have very much to convert. You were very under-medicated when those labs were done. Even so, it is impossible to guess how much you are eventually going to need. And, you need what you need, no matter how much it is.


It's strange that we don't have stronger pills than 200 mcg available in Europe, when apparently Synthroid exists in 225, 250, 275, and 300 mcg pills in the US...


Well, does it really matter? You can take a 200 mcg pill and a 25 mcg pill if you want 225 mcg. But, apparently, maths wasn't this doctor's forte - nor logic, come to that!

But, I guess, with doctors like that, there just isn't that much call for tablets over 200 mcg in Europe! So, they don't bother to make them.


No, it does not matter, except maybe it could make doctors aware that some patients do indeed need to take more than 200 mcg daily...but maybe it's just as well. Now, we just split pills or buy extra pills on the side and add as much as we need, while doctors believe we never take more than 200 mcg...:-)


lol I don't think they'd take the hint, anyway!



A person without a thyroid gland is going to require a much higher dose than someone newly diagnosed usually. If all the Levothyroxine doses were averaged what use is that to someone for whom the averaged dose is too much or too little?

125mcg is not a low dose but I don't know whether it is an average dose.


Thanx Clutter. I think I'm just trying to work out where I am in all of this. Your helps appreciated lots.



If it helps my sister's thyroid was ablated with RAI and she is prescribed 100-125mcg. I had a thyroidectomy and I take the equivalent of 165mcg.


That's for calculating the starting dose of people that have had a thyroidectomy, isn't it? Doesn't really work for other people. You might need a lot more, or a lot less.


Quite right greygoose.

a) Not all cells are the same size. So simple weight does not directly reflect number of cells. Classic is myxoedema - adds weight with no extra cells. Even if, overall, heavier people have more cells than lighter people.

b) Need depends on numerous factors including our lifestyle - live in the Arctic and work extremely hard fishing, etc., you'll need more than an otherwise identical person in an sedentary job in an air-conditioned office.

c) Absorption is far from 100%. But how far varies. Two people who need exactly the same amount actually arriving into their bloodstreams might need to take very different doses as tablets (even if the same tablets).

d) Delivery technique of the active ingredient affects absorption. It appears that liquid levothyroxine products tend to be more evenly and completely absorbed. The Teva product withdrawal of a few years ago is evidence that a single ingredient can make a considerable impact.

e) The same person varies in requirements. Witness the classic "Do I need more in the winter?" to which the answer seems to be "Some people do."

Finally, whilst the original poster is perfectly reasonable in wishing to know, in the end, so what? If I need 112 micrograms and you (whoever you are) need 250 micrograms, does it actually matter to me, to you, or to anyone else?

The weight-based estimation can identify people who need higher doses by comparing an individual's dose-per-kilogram against some average. It does absolutely nothing to identify why that is the case.

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