Dose of levothyroxine

[sunsetalley]

What factors determine dose of levothyroxine? I konw some people who are taking levothyroxine but they're on so much lower doses than mine despite being older and heavier than me and they say they are satisfied with their treatment. I still haven't seen anyone taking more than 100 mcg daily except myself.

Can anyone explain why this happens?

Thanks in advance...

[shaws Administrator]

It all depends on how our body reacts to thyroid hormones.

The majority on this forum are people who - in the main - feel worse on levothyroxine or the doctor will not increase dose until the TSH is 1 or lower. The doctor may also prescribe another medication for the 'symptom' but doesn't increase thyroid hormones.

Many doctors believe if the TSH is somewhere in the range - even up to 5 that we're on a sufficient and refuse us an increase. They do not realise we need increases to enable our T3 receptor cells to have sufficient T3 (converted from T4). They never check FT4 and FT3.

One doctor I know who was Thyroid Hormone Resistant had to take 150mcg of T3 (liothyronine daily). I take less than 40mcg. It varies according to our bodies' needs. Levothyroxine (an inactive hormone) has to convert to T3 (the Active hormone) and it is T3 within the millions of T3 receptor cells that enables our bodies to function and relieve painful symptoms.

[sunsetalley in reply to shaws]

Thank you for replying...

[SlowDragon Administrator]

In the past the standard dose was between 200mcg and 400mcg

See top of right hand column on page 2

rcpe.ac.uk/sites/default/fi...

Now it's typically somewhere between 100mcg and 200mcg ......but many people are under medicated and low vitamins as a result

NICE guidelines saying how to initiate and increase. Note that most patients eventually need somewhere between 100mcg and 200mcg Levothyroxine

cks.nice.org.uk/hypothyroid...

TSH should be around one and FT4 towards top of range and FT3 at least half way in range

Very important to test vitamin D, folate, B12 and ferritin too

All thyroid blood tests should ideally be done as early as possible in morning and fasting. Do not take Levothyroxine dose in the 24 hours prior to test, delay and take 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)

[sunsetalley in reply to SlowDragon]

Thank you for replying...

[Aurealis]

I see shaws and Slowdragon have made sensible replies.... I was just tempted to say ‘the IQ of the GP’ (naughty)

[greygoose in reply to Aurealis]

lol That has to be a factor!

[MaisieGray]

The dose is whatever you need, as an individual with an individual set of circumstances, to achieve the nirvana of being euthyroid and symptom-free; and you can't accurately compare yourself with others. Gender and weight (or more accurately as one study had it, lean body mass) might help in guiding initial prescribing, but thereon in its more a case of "see how it goes".

[sunsetalley in reply to MaisieGray]

Thank you for replying...

[serenfach]

The Endo I recently saw (who only went by TSH) and dismissed the need for T3, boasted he had some poor woman on over 600mcg daily. Calling him cruel did not go down too well!