Does NDT have a diuretic effect that levothyroxine doesn´t?

I have read several posts by people who switched from levo to NDT and lost quite a lot of water weight in the first few days/weeks...someone compared it to taking a diuretic drug. I have read in the past that some of the weight gain in hypothyroidism is water weight and not fat, and that fluid retention is what gives many hypo patients a puffy face and swollen fingers. Not that most doctors have a clue about that, though. One doctor I raised this with told me that only salt will cause fluid retention, not hormones...

But my question is: is there anything - and, if so, what? - in NDT that will cause you to lose the extra fluid and that is not found in levo? The posts I´ve read only talked about NDT vs levo so I have no idea if synthetic T3 could have the same effect as NDT.

[greygoose]

NDT had the opposite effect one me! On synthetic T4+T3 I had been losing weight. But, as soon as I started NDT, I started putting it back on and blew up like a whale!