Maximum dose of levothyroxine?

[PolkerrisBeach]

Started on levothyroxine tablets about 9 months ago, first on 50 micrograms, then up to 75, then 100. Just had a call from GP saying still not good enough and up to 125.

How many more times could it potentially go up? Is there a maximum dose? I know only one other person with an underactive thyroid and she's only on 50.

“Levothyroxine doses are dependent upon the person’s body weight. Most patients require between 100 and 150 micrograms a day, but the dose can be lower than 75 micrograms or up to 300 micrograms a day, depending on your needs.”

www.btf-thyroid.org/information/leaflets/29-hypothyroidism-guide

I'm on 175mcg (been on it for about 10 years), my SIL is on 150mcg and has no thyroid (removed), I have another friend who has been on 125mcg for years. Not sure on maximum though, but 125mcg doesn't sound high to me - my understanding was that you had to start low and build up to what works for you - as you are recently diagnosed it seems about right, I think I was about 2 years in when I finally got the right dosage for me.

Ah, that would explain my dose being higher than SIL - I'm a lot taller and fatter than her!

Yes that's what the doc said - the aim is to get the lowest possible dose which works for you.

Really could do with dropping a few kilos too..... (me, not the doc).

There are people out there on 300mcgs and sometimes more. The important thing is to find a dose that relieves your symptoms, which will probably mean that TSH is really low (perhaps even below the reference range- this doesn't matter) and FT4 is at the top of the reference range or even a bit above (again this doesn't matter).

Keep going back and getting checked every six weeks until you get to a point where you feel well again. If our dose keeps going up and you don't feel any better, ask for a referral to an endocrinologist. You may need a different drug.

From what I can remember , you start low and with regular blood tests in the first year or two have the dosage gradually increased until it's the correct amount , in many cases it can mean that it may decrease as well after a time ... mine went 50 , 75, 100, 150, 200, 250 , then after some time and annual blood tests was decreased again over another period of time 225, 200 150. And has been steady on 125 now for about 3 years

You need to ask your GP what your results are and work out what is not working. Some people are not able to convert properly from Levo (synthetic T4) to the active thyroid hormone FT3, which is the hormone that the cells in your body actually need.

Some people end up with really high levels of FT4 swilling around in their blood stream & feeling a bit toxic or unwell but they aren't converting to the useful stuff and so they still feel hypothyroid too.

Has your GP checked your vitamin & mineral levels? Poor levels can inhibit conversion.
Has your GP checked your thyroid antibodies to see if you are hypothyroid because you have Hashimoto's disease?

Good advice from @Margo

I’m on 300mcg. Always been 200+, apart from DS1 pregnancy when it went to 125.