I have dyed my hair A LOT and I want to fix it!!!!!!?

My hair has gotten thinner and also not as much grows anymore, i have stopped dying it and also got my hair significantly cut shorter to get as much of the damaged hair off, i'm using john frieda's repair products, and have noticed softness, but what else can i do any food i could eat more of or treatments that would help i have heard of nioxin is that any good? THANKS!!!!