How Long Does It Take For Regrowth Of Hair?

hey iam 17 i was on protein less diet means that i was taking less protein intake and i was dieting excessively after one month my hair started falling rapidly and started thinning, then i came to know its due to the protein less intake and malnutrition so i started eating very much now... its like 1 month my hair falling is decreased but i want to ask that how much time will it take for regrowth of my hair that has been already fallen?