Some people claim that eating more gelatin can strengthen your nails, but there's no evidence to back that up. But a recent study done in Germany found that people with nail problems who took 2.5 mg of biotin a day wound up with stronger nails. You can look for biotin supplements in the store, but the study said that to get the effect, a prescription dose was required, so you may need to talk with your doctor.
The other ways to make your nails stronger are not what you might expect. Do not cover them with polish, which you then remove with acetone weekly or even more often. Don't mess with your cuticles, and don't use nail hardeners, which can actually make your nails drier, weaker and more prone to breakage. Use a nice hand cream to keep your hands, nails and cuticles softened and moisturized, and do as little to your nails as possible. Don't soak them in things—that doesn't work.
Your nails may be breaking because of the chemicals they're subjected to. Manicures are notoriously rough on nails; emery boards cause splitting and tiny breaks, so use a nice, diamond coated nail file instead. Dish soaps and shampoos dry your nails and may even cause allergies, so consider switching to milder household soaps.
