@Gerryb I was also concerned about using anything with formaldehyde in it. I used OPI Formaldehyde Free Nail Envy Strengthener for sensitive nails. It contained Vit E, Kukui Nut Oil and Aloe Vera to soothe the nails. I applied it just before each chemo, adding coats every few days as is recommended. My nails were stronger than they normally were before chemo! I also used ice gloves for the Docetaxel part of my chemo. I think the taxol type chemos are harder on nails. My nails survived with only discolouration to the thumbs.