Until 5 years ago I used to bite my nails. I gave up & decided to do something with them. I had a go & people say they look lovely & ask me who did them for me. They even said they looked better when I did them than when I had them done professionally for my holiday. They peel a lot though as I'd bitten them all my life before then & I'm 33. I've used all different nail hardeners, peeling & brittleness solver & vitamin & mineral nail varnishes to help. They can only do so much. I guess I can only carry on using them & wait & time will heal the damage.