1 grain of NDT is stated to be around 100mcg of levothyroxine. 20mcg of lio is around 60mcg of levo. We can do a straight swop from one to another without problems.

If you prefer you can start with a slightly lower dose.

Take note of pulse/temp and if either rises, reduce dose slightly. Taking account of your clinical symptoms you can also add a small amount every 2 weeks. The aim is relief of syptoms.

Thiroyd is said to contain 35 mcg T4 and 8.31 mcg T3 per grain; other brands contain 38 mcg T4 and 9 mcg T3.

So, for near equivalents to your current dose, 3 grains of Thiroyd would supply 105 mcg T4 and 24.93 mcg T3, while 2.5 grains of other brands would supply 95 mcg T4 and 22.5 mcg T3. You may prefer to start on 2.5 grains of Thiroyd or 2 grains of other brands, plus 25 mcg of levothyroxine every day or two.

Hi Suzy, are you taking your meds all in one go? If so then I wonder if spacing your dose into 2-3 smaller doses each day might alleviate the headache. I used to take a combo of T4 and T3 like you, and found multi-dosing helped, as did fully recovering - hardly ever get a headache now. Now I’m on NDT and T3, which I take in three doses at 5:30am, 11:30am and 4:30pm. A bit of a pain at first, but I’m used to it now, and it works for me. Maybe just try splitting it into a morning and afternoon dose. All the best with it, I hope you feel better soon.