Terbinafine
"I lost my fingernails suddenly about a year ago. I spent over half a year trying at home  remedies but nothing worked. I've been taking this medication for about 5 months now and I will tell you this - It doesn't work fast but if you stick with it the nausea and side effects will eventually die down and you will eventually start growing new nail. My two worst nails (my thumbs) are still oddly shaped, but when I look back at the photo I took the first day I realized that the nails were separating from my bail bed, I can see that I've gained back quite a bit after about 5 months. I'm not sure I will ever have my beautiful nails back, but this medication has given me hope that some day (maybe years from now) I will be back to normal."