I have heard that it is from a deficiency of certain vitamins, but I don't recall exactly which vitamins they were. It was something that I never would have guessed, like Zinc or something, but that may not have been it. If you wish to experiment, you might try taking a multivitamin, and don't forget that it will take months for the nails to grow out and for you to see the results. I have trouble swallowing those huge, hard-as-a-rock adult vitamins without choking, so I take the childrens' chewable kind - seriously!