Hair problems can include hair loss, brittle or fine hair, oily hair, or dandruff. All hair problems are treated differently, but most remedies treat both the hair and scalp. Excessive hair loss or thinning can be a result of poor nutrition, abuse of heat styling tools, or extreme pressure from hair clips. By over-processing your hair with the chemicals found in permanent waves, hair coloring, and hair straightening, you subject it to drying and breaking. Chemicals used in these processes open the hair shaft in order to add color or change the texture of the hair. When this shaft is opened, moisture is lost, which causes hair to become brittle and break easily. While dry and brittle hair may be aggravated by the overuse of heat styling tools and chemicals, oily hair is caused by the same overproducing oil glands that are found in the skin. Complete cleansing with a shampoo made for oily hair will keep oiliness under control. Another common hair problem is dandruff, which occurs when skin cells on the scalp reach the surface before they are fully mature, causing the skin to flake off. Although there is no cure for dandruff, mild cases may be controlled through the use of over-the-counter dandruff shampoos. Baldness, especially in men, is hereditary and cannot be prevented. However, it can sometimes be corrected by surgery.