Brittle nails, falling hair and allied conditions. Hair grows from follicles in the skin which are nourished by blood vessels. The appearance and health of the hair often reflects the health of the body as a whole. Nails from the nail beds on fingers and toes have a protective function. During illness, nails may cease to grow and Combination K has a particular combination of three tissue salts that may be effective in different aspects of the maintenance of hair and nail health.