I don't have very brittle nails, but I have this a try when I felt my nails felt a bit weak. This amazing nail strengthener contains Epoxy Polymer, Calcium Complex and Titanium. With these three unique ingredients all put into one, it's the ultimate nail strengthener. It can reinforce nails, protect against breaking, peeling or splitting, it can mend, bond and heal weak and fragile nails. Plus it contains Pro-Vitamin B5 and Iron helps strengthen and enhance the structure of the natural nail to help nails grow longer and stronger. You can notice results after your first application. I also use it as a top coat because its so strong, it keeps nails looking amazing for longer plus it adds an extra shiny top coat which enhances the colour of the polish, making polish look much more intense and gel like.