Sebum

The scalp contains a natural oil called sebum, which helps keep the skin lubricated. Sebum is produced by the sebaceous glands. Sometimes these glands work overtime and produce too much oil, leading to a greasy scalp. Greasy hair can look dull, limp, and lifeless, and it may be more difficult to manage. To treat greasy hair, try washing with a gentle shampoo that is specially formulated to control sebum.