Another key factor is how well you are digesting and absorbing nutrients from your food. Low levels of stomach acid, which prepares minerals for absorption, and digestive enzymes, are a common problem. A supplement containing both of these can really boost the condition of your nails, although note that you shouldn' t take it if you' ve had stomach ulcers or other stomach problems. And don' t forget to protect your nails from external damage, such as harsh detergents and hot water.