My nails are a mess lately. I take a lot of supplements (D, B12, biotin,  multivitamin, fish oil) so talk to your doctor and see what they recommend for combating your deficiency. 

I use a nail strengthener called REBUILD from Seche Vite as a base coat under my nail polish, along with a top coat from the same brand. Both have done wonders for me and actually work. You can find them both here in the Chronic Curve store. The top coat is super thick, glossy, and keeps my nails from chipping and peeling for at least a week before I have to repaint and use the strengthener again.

Definitely try those out and see how they work :) If you order through my Amazon store (linked above), I get a small commission and would  be very grateful to you :)