Levo to NDT conversion

I have been toying with the idea of NDT or T3 for a while but wanted to give Levo a decent chance first. I have decided to trial an NDT as T3 sourcing is so problematic right now. My FT4-3 conversion could be better even after sorting my nutritional deficiencies plus I need to rule Levo in or out as the root cause of the muscle/joint/ back issues which only developed since starting Levo 16 months ago.. I am leaning towards thiroid-s which I believe has 38mcg T4 and 9mcg T3 per grain.

I am a bit mathematically challenged and cant work out what the rough grain equivilent is to 150mcg levo to make sure I buy enough for a meaningful trial without going overboard if it turns out not to suit. Also what sort of dose should I start at? How long should it take to purge the levo once I switch? I took a guess at 6 weeks as thats how long it takes to assimilate when adding Levo, with a possible further 8 weeks to finish titrating the NDT (every 7 days?) get stable and evaluate improvement or lack.

I could swear I saw a list of NDT with T3 / T4 levels and how to convert a few days ago but I'm damned if I can find it now!! Might have been an admin reply?? on someones post or posibly an old thread. Or I plain imagined it!!

Any advice gratefully received

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6 Replies

  • Phoenix605,

    150mcg Levothyroxine is equivalent to 2.5 grains NDT but if you've not taken T3 before it's not advisable to do a straight swap over. Most advice is to start NDT at 1/2 to 1 grain and increase in 1/2 grain increments every 2 weeks. You are likely to become very hypothyroid this way. I would advise reducing Levothyroxine to 75mcg and introducing 1 grain NDT. 2 weeks later you can stop Levothyroxine and increase NDT to 2 grains. 2 weeks later increase NDT to 2.5 grains. Hold at 2.5 grains x 6-8 weeks and have a thyroid function test including FT3 before increasing further.

  • Thanks Clutter that is perfect, I just couldnt get my head around it and would have ordered waaay too much.

    Do you have any thoughts re how long it should take for me to be 'clear' of Levo and for any residual effects to at least start to clear up. It is so frustrating, I thought I was doing relatively well on Levo and am lucky to have a good GP, who ignores the NHS TSH results in favour of symptoms and private FT3/F4 results but we were both stumped with the tendonitis and ligament pulls for no reason so fingers crossed this works!

  • Phoenix605,

    Most Levothyroxine will be out of your system 4 weeks after last dose but there may be traces for up to 8 weeks.

  • Great, Thanks Clutter, so with two weeks at reduced levo included, I wont be surprised if I dont see any real physical improvement for around three months, factoring in some healing time. Hopefully the benefits of the T3 component will be well established by then too. I will aim at a 4 month trial initially then it will either be back to 'free' Levo or fess up to GP whilst bouncing around like a spring chicken 🐣🐣

  • Phoenix605,

    Most people find some improvement almost immediately NDT is added as the T3 is quick acting. 4 months while you are titrating Levothyroxine and NDT doses is unlikely to be sufficient. 4 months after you are optimally dosed on NDT is a reasonable trial.

  • Brilliant, thankyou, no point giving up too soon!

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