Welcome to Healthcare Magic,
As per your query your sister have retarded hair growth. I can very well understand your concern for your sister.
Thre are certain conditions of the har where we find early breakage of hair. I think till now you were not guided about your sister's condition. Hair problems are definitely the problems which take a long time of months before it can be sorted out. You need to have a good follow up of at least 6 months before you think of changing any doctor.
Even then for the best of the remedy you make her follow a good dietary plan in your daily schedule. You should know that our hair are basically made up of proteins
and supported by certain simple biochemical known as minerals and vitamins. So every of the food item which contains good amount of proteins with vitamins and minerals
are best for maintenance and growth of good hair.
So let her eat a lot of fruits, green vegetables, sprouts and milk products in your diet.
Hope this information helps you. If you have any further queries I will be happy to help.
"Wish you good health"
Dr Sanjay Kumar Kanodia