Sebaceous refers to anything related to sebaceous glands, which are small glands in the skin that produce an oily substance called sebum. This oil helps to keep the skin and hair moisturized and acts as a barrier against bacteria. Sebaceous glands are found all over the body, but are most concentrated on the face, scalp, and back. Sebum production can vary from person to person and can be influenced by factors such as hormones, diet, and skin type. Excessive sebum can lead to conditions like acne, while insufficient production can result in dry skin. Maintaining a balance is essential for healthy skin.