Any thoughts please on why erfa is the only thyroid medication than helps in my case, all others cause relentless migraines

[AmberBee]

Initially I started levothyroxin that was horrendous at the time with awful adrenal causing a whole load of unpleasant symptoms, t3 thybon brand I have also tried without success.

I started on NDT around 15 years ago but had to build up slowly over a few years as it caused wired & tired symptoms causing stress.

After trying armour and others I tried erfa due to cost of armour to find it helped more than others but why does erfa help more than any others?