Brittle NailsBrittle nails - and split edges - are almost certainly caused by putting your hands in strong detergents or by using nail varnish solvents too often. There are numerous branded products available for the treatment of brittle nails. But the best solution is to take care of your nails more carefully! * When washing up use rubber gloves. Modern chemicals are strong enough to strip metal - they'll ruin your skin and nails. * Use a long-handled mop if you do any dishes without your rubber gloves * Try not to change your nail varnish too often. If varnish gets scratched or chipped, touch-up rather than remove and repaint. Cleaning off nail varnish can weaken your nails. While your nails recover keep them short - to minimise the risk of breaking them. I don't think any products sold to harden or condition your nails are worth buying. But do use a moisturising cream around your nails.