Brittle nails say a lot about your habits, and overcoming these habits will help nails heal. Dermatologist Robin Ashinoff tells Cosmopolitan that brittle nails are a result of "environmental factors and habits that dry out nails, such as frequent hand-washing and drying and/or chronic use of polish remover and artificial nails." She says if you eliminate those factors, nails will be healthier, and if they don't, it might be due to a vitamin B deficiency, which suppliments can correct.