I've never used betadine. I am sure there are extra things people could take to get better results but my results are from dermaroller, minoxidil and occasional Nizoral use. I smoke and my diet is not good.
I'm not suggesting that betadine won't help - I have no idea - but, from my experience, it isn't key to getting results.
You are an exception. More people than not had success with betadine. Even the dude from the foreign language forum who was rolling hard uses it