Can chemotherapy cause problems to the nails?

Chemotherapy can definitely have an adverse effect on hair and nails. It is certainly possible that your client’s “eggshell” nails may be related to the treatment she is receiving. There is no foolproof way to find an application that will, work consistently as would be the case with normal, healthy nails. I can only suggest, as you are already doing, that you by different applications until you find one that works best. -- Dr. Scher