The 5 Biggest Hair Myths...and One Unfortunate Truth

5. If you shampoo less often, your scalp will gradually produce less oil.

No matter how frequently you shampoo, your scalp produces the same amount of oil, says Jeffrey Benabio, MD, a dermatologist at Kaiser Permanente in San Diego. Cutting back on shampooing will have no effect on your sebaceous glands; genetics and hormones determine the amount of oil they produce. But it will cause dirt and oil to accumulate on your scalp and hair follicles, and could cause inflammation and irritation that might stunt hair growth. All experts agree: How often you wash your hair is a personal decision. Use your judgment. Wash your hair with a moisturizing shampoo when you feel you need it, whether that's daily or weekly.