My understanding is that they work for some people but not for others, Sandra. I've been taking Nutri Adrenal for a few months. It's had a very small effect - less "brain fog" and more ability to concentrate - but not a lot. I haven't tried Nutri Thyroid as I understand from Dr P's book it's important to get the adrenal function right first.
I guess the answer to your question is - it all depends on the individual and how long you've been ill for. In my case, for example, I've been ill since the 1990s - so I'm expecting it to take a very long time before I feel any better, if at all.
As I mentioned on your other thread, I'm going to see Dr P myself next week. I'd got to the stage where I'm not sure what I should do next - keep on with the NA, add NT or even try NDT - so that's why I'm going to see him. I suspect what he will do - and what he's probably doing with you - is to try the Nutri products first to see if they help, before suggesting NDT. Please don't expect an immediate miracle - I suspect it's a long, slow process!
As to diet, I've no idea until I see Dr P. Take a look around this forum, and the main site, and the internet generally. There is lots of advice out there about what not to eat with hypothyroidism.