Converting T4/T3 combo therapy to NDT ...

[Pamela0106]

I’ve read a few historical posts on these points and I’m struggling to get my brain round the conversion calculation because of confusion over what the bioactive equivalence versus total equivalence is.

So with that said I thought I would just ask the straight question on my own specific doses so I could get my head round it.

What would the correct equivalent NDT dose be for the following 2 examples:

Person A - Currently takes 75mcg Levothyroxine and 10mcg T3

Person B - Currently takes 100mcg Levothyroxine and 10mcg T3

Any help in the simplest of explanations would be appreciated. Lol xxx

[shaws]

NDT is usually measured in 'grains'. It is stated that 1 grain is around the equivalence of 100mcg of levothyroxine. NDT contains T4, T3, T2, T1 and calcitonin. You will also find some NDTs state 60mg or 65mg. = 100 mcg approx.

75mcg of levothyroxine plus 10mcg of T3 (equaivalence of T3 = 30mcgT4.) I

In UK the dose is 20mcg T3 (60mcg of levo) but other T3s are 25mcg which is around 100mcg of T4.

[Pamela0106 in reply to shaws]

See this is how I got confused (and I know it’s something to do with bioactive element perhaps but you said 1 Grain = 100mcg Levothyroxine and yet Jackie (below) said 1 Grain = 65mcg (38mcg T4 + 9mcg T3). Assuming Jackie used 3:1 ratio for the T3 to T4 conversion.

So is it 1 Grain = 100mcg or is it 1 Grain = 65mcg in Levo equivalent?

[Clutter]

Pamela016,

1 grain NDT contains 38mcg T4 plus 9mcg T3 which is equivalent to 65mcg T4.

75mcg T4 plus 10mcg T3 is equivalent to 105mcg T4 or just over 1.5 grains NDT.

100mcg T4 plus 10mcg T3 is equivalent to 130mcg T4 or 2 grains NDT.

[Pamela0106 in reply to Clutter]

This makes perfect sense to me but Shaws reply confused me a bit because of the whole 1 Grain = 100mcg levo thing.

I’m sure I’m being thick somehow! Are you both saying the same thing or different? 😂

[Clutter in reply to Pamela0106]

Pamela0106,

NDT manufacturers say that when switching from Levothyroxine to NDT 1 grain is bioequivalent to 100mcg ie the effect is bioequivalent to 100mcg T4 which many think is an overstatement anyway. If you are already taking T3 with T4 then it is better to work on the actual content of the T4 and T3 in NDT which is what I posted above.

[Pamela0106 in reply to Clutter]

Hey Jackie. Hope you’re well. I’m going to an appointment in the next couple weeks and want to take some NDT documentation along with me. I’m searching online but struggling to find so wondered if you could send me a link to where it says the actual T4 and T3 content is 38mcg and 9mcg respectively. Could you drop it below in a reply or PM it to me at all? Xx

[waveylines]

May I add that in addition when switching its probably wise to start a little lower than the straight conversion. For example instead of 2 grains I would start at 1 1/2 grains. This is because your uptake maybe a bit better on a ndt. You can always raise it if you feel its leaving you under medicated.

I did this and then raised it to my actual equivalent dose in two week blocks. After that any increase needed I resumed the standard wait of 6-8 weeks before reviewing. Hope it works for you.