At the very bottom of the page is a chart that shows the ERFA and equivalent T4 and T3 med.
You'd need 48.5 mg ERFA to equal your 75 synthroid.
I agree that most sites use a conversion factor of one grain of desiccated equals 100 mcg of T4. I just wanted to point out that there are other sites that suggest one grain of desiccated for 75 mcg of T4. The difference is their underlying assumption about the relative biological activity of T3 to T4.
For example, one grain of desiccated contains approx. 39 mcg of T4 and 9 mcg of T3. If we assume that the T3 is 4 times as active relative to T4, then 4 times 9, plus 36 equals 75. Other sources say that it should be higher than 4 times the effect of T4. Various sources suggest using a factor of up to 8 times as effective. Similarly, this would yield 8 times 9, plus 39, which would be the equivalent of 111 mcg of T4.
I am not trying to belabor this, but I think it is important for members to recognize that if their doctor switches them from a T4 dose, based on one grain of desiccated for each 100 mcg of T4, they may be getting shortchanged in the conversion. So. if hypo symptoms result, this may help understand why it happened.
According to the chart, at the link I provided (ERFA Sciences, Inc), 1 grain of ERFA is 65 mg, not the 60, we usually see, and it's equal to 100 mcg levo. It would appear that not all brands of desiccated are created equal?
I agree, there are lots of opportunities for misunderstanding. I assume that the 65 mg of Erfa must have the same amounts of T3 and T4 as 60 mg of Armour, based on the table, but could not find info to confirm.
Another problem I have is that they say that 65 mg of Erfa and 60 mg of desiccated is equivalent to 100 mcg of T4 med, and also equal to 25 mcg of T3. That doesn't follow. If 100 mcg of T4 were the same as 25 mcg of T3, then they are using a 4:1 ratio.
If I use that ratio and the amounts of T4 and T3 in desiccated (38 mcg of T4 and 9 mcg of T3), and convert it to the equivalent dose of T4, it would be calculated to be 38 plus (4 times 9), which equals 74, not the 100 mcg of T4 shown in the chart.
So there is a discrepancy in the data. Either the 100 mcg of T4 is wrong, and it should be 74 mcg, or the 25 mcg of T3 is wrong and it should be more like 15 mcg of T3.
So yes, not all brands of desiccated are created equal, and apparently not all numbers in the chart are calculated correctly either. Am I missing something here?
"Am I missing something here?" I think we all might be. LOL Not sure what it is, though.
I couldn't find anything that gave the actual amounts of T4 and T3 in each grain either; not sure if it's safe to assume they are the same that we normally see or not. If 1 grain of ERFA is 65 mg and equal to 100 mcg, could that mean a grain is actually stronger than other desiccated meds? Could that be why more people seem to do better on ERFA? Just a thought.
If that were the case, then why would they show it as equal to 60 mg of Armour or Nature Throid desiccated? I suspect that it has the same amount of T4 and T3, but more filler. I have no idea why some people report doing better with Erfa. I just sent an email to the producer to find out the actual amount of T3 and T4 per 65 mg of Erfa.
Not arguing, but this raises a whole new point........ or maybe, just a new point for me?
"I suspect that it has the same amount of T4 and T3, but more filler." New question............ What's actually being measured in those mg? I was under the impression (smack me if I'm wrong, but don't hit too hard, cuz it might hurt....lol) that the mg pertained to the amount of "active ingredients", like levo (100 mcg pill has 100 mcg active ingredient) or cytomel (5 mcg pill has 5 mcg active ingredient) - the fillers/binders are in the pill, but aren't included in the dosage.
I've always been under the impression the the mg/mcg of a medication pertains to the active ingredient/s, not the total content of the pill.
No argument here, Barb. Just trying to help make sense of something that is somewhat confusing, even for those who have been around the Forum for a while.
With regard to T4 and T3 meds I'd say that you are exactly correct. As you said a 100 mcg pill has 100 mcg of active T4. Not so with desiccated. A 60 milligram pill of Armour (60,000 mcg), contains only 38 mcg of T4 and 9 mcg of T3. Wonder what the other 59,953 mcg are. LOL
Hmmmmm......... As you can see, I'm a little slow sometimes.... lol.
Will be interesting to see if the producers answer your e-mail, and what that answer is.
so after all your calculations :-D (I don't understand the conversion) How much Erfa corresponds with 100 Synthroid/Levothyroxine?
This is a very old thread and as I recall, the conversation was left right where it ended... I don't think gimel ever did let me know what he found out from the manufacturer, if he ever heard from them... Perhaps, he'll pop in here and let us know. If not, I'll contact him and ask him to.
Somehow I never got an answer from the Company; however, there are conversion tables that show:
100 mcg of T4 = one grain of NDT = 25 mcg of T3
This is wrong because this suggests that T3 is 4 times as potent as T4, in which case the grain of NDT (39 mcg of T4 and 9 mcg of T3) would be equivalent to only 75 mcg of T4 (39 mcg of T4 plus (4 times 9 mcg of T3)) equals 75 mcg of T4, not 100 mcg. Further, I have seen a scientific study that concluded that the correct ratio between T3 and T4 was 3.3, not 4. Also, the AACE/ATA Guidelines mention a study that concluded the ratio should be about 3 to 1.
So taking all this into account, I have concluded that the best conversion between T4 and NDT type meds is 66 mcg of T4 to 1 grain of NDT. This conversion factor comes from the following calculation: one grain of NDT = 39 mcg of T4 plus 9 mcg of T3. Using the ratio of 3 to 1, then 39 plus (3 times 9) is equivalent to only 66 mcg of T4, not 100 like shown in conversion tables. This makes a big difference in dosage when switching from T4 to desiccated types of thyroid med like Armour Thyroid and Erfa..