Conversion of Levothyroxine to Erfa

[Pinebunny]

I've been advised to take 175mcg of Levothyroxine or 60mcg twice daily of Erfa.

How dies conversion work? The info I can find shows part is T3 and Part T4, usually 38mcg. It's a bit confusing?

[MaisieGray]

60 mcg of an NDT is 1 grain. I grain contains 38 mcg T4 and 9 mcg T3.

If you are taking it twice daily, that gives you 76 mcg T4 and 18 mcg T3.

There's no single agreed equivelance of T3 to T4, but if you work on T4 = 4 x T3, that gives you

76 + (4 x 18) = 76 + 72 = 148 mcg T4

If you use the multiplier T4 = 3 x T3 used by some, then obviously that would give you a lower figure

76 + (3 x 18) = 76 + 54 = 130 mcg T4