1. The recommended dose for levothyroxine is 1.6mcg /kg of body weight. Are most thyroid patients on this dose?
2. If I wanted to switch from T4/T3 combination to only T4 medication to check if my conversion has improved after making healthy changes for a year, how long would I have to be on T4 only to know the result ?
Thank you so much x
You can read my discussion on the dose by weight here:
helvella - Estimation of Levothyroxine Dosing in Adults
A discussion about the use of formulas to estimate levothyroxine dosing. Includes link to a downloadable spreadsheet which calculates several of these.
Thank you for replying Fruitless. Are you on levothyroxine only or do you take extra T3 ?
I’ve been wondering about that lately. Mine would work out at 110mcg. But I was on 100mcg until 2 weeks ago when I was told I was on too high a dose.
After an argument about it with a doctor I was still put down to 75mcg. Last time I was on that I could barely move from tiredness. So I wait in anticipation for my next blood test in a few weeks, just to see what it throws up.
Yet another extremely heavy handed dose adjustment.
Do they really think that, even if you genuinely should have your dose reduced, it is better to drop by 25% in one go rather than, say, 12.5% at first and another similar reduction in a few weeks?
I don’t have an answer on your conversion approach, but one day think I will switch from my current Levo/Lio combo back to Levo only. I was put in Lio way too soon, and I’m not so sure I really need it, but who knows!
I’d be less concerned about how long it would take to see if you are a good converter and more concerned with the standard risks of volatility in our bloods. You can be on a single dose for years and feel fine, switch back and forth and then never be the same. Hormones are unpredictable. So if and when I do it, I’m going to treat it like the most sensitive titration ever done! As low and as slow as I could.
Tricky.
If you have DIO1 mutations there was a study published this month from Jordan which I believe applies to me . The purpose of the study was to do with researching the possibility of setting an appropriate weight based starting dose for levo for those affected. The evidence was robust that in my particular case 1.3mcg/kg body weight would be appropriate. I'm not clear if age,sex etc. varied this at all . Based on my weight this suggests an 81mcg levo dose for me . I think my optimal dose will be a bit lower than this, but I take liquid levo and may be getting 100% absorption because of this. The research, I imagine , probably assumes levo tablets where absorption is likely much less. You probably haven't tested yourself for DIO1 mutations, but if you are positive for these in a particular combination, then I would agree with their findings , as far as I can ascertain at this stage, that 1.6mcg/kg body weight dosing would appear likely to be excessive in my particular genetic circumstances.
75 mcg levothyroxine 
What to expect when on Levothyroxine?
Starting Dose Questions. Levothyroxine or Armor
Test before or after Levothyroxine 
