Can you compare Erfa to the synthetic version?

[Guest guest]

Hi again

Could anyone tell me what the equivalent 2g of Erfa is for any of the synthetic versions - Levothyroxine for example? Can you compare them? I am at the specialist on Friday and if he says he has no idea what Erfa is equivalent to in the synthetic world I would like to give him an answer.

Thanks again

[Guest guest]

Hello ,

There is a chart that compares Armour with synthetic thyroxine (pls see below) – but I have to stress that there is now way you can compare it `like for like' because natural thyroid works in a very different way to synthetic thyroxine. For a start, natural thyroid has got T1, T2, T3, T4 and Calcitonin in it, whereas thyroxine is only the pre-hormone T4 and the body is required to convert T4 into T1,2 and 3.

If youpreviously, say, only tolerated 125 mcg Levothyroxine, for example, then that does NOT mean that 1 ½ grains of an NDT will be enough for you. It takes what it takes – everybody is different. For instance, my own personal limit on Levo had been 125 mcg per day. I am now on 2 ½ grains of NDT and doing very well. There is no way I would have been able to take the "equivalent" approx 220 mcg of Levo. You simply cannot compare the two products – they work in different ways.

Your TFT levels are "right" when a) you FEEL right and your FT3 is between the middle and the top of the ref range, your FT4 will then be slightly under half way of the ref range and the TSH will most likely be suppressed - which is perfectly all right... don't let anybody tell you otherwise or scare you with tales of osteoporosis and heart failure... - most endos just love doing that.

Best wishes,

Armour Dosages

Approximate Thyroxine(T4) Equivalent

1/4 grain9.5 mcg T42.25 mcg T3

18.5 - 25 mcg

1/2 grain19 mcg T44.5 mcg T3

37 - 50 mcg

1 grain38 mcg T49 mcg T3

74 - 100 mcg

1 1/2 grain57 mcg T413.5 mcg T3

111 - 150 mcg

2 grain76 mcg T418 mcg T3

148 - 200 mcg

3 grain (bisected)114 mcg T427 mcg T3

222 - 300 mcg

4 grain152 mcg T436 mcg T3

296 - 400 mcg

5 grain (bisected)190 mcg T445 mcg T3

370 - 500 mcg