What is produced by the sebaceous gland that helps lubricate the skin?

Sebum is the substance produced by the sebaceous glands, which are found in the skin. This oily secretion plays a critical role in maintaining skin health by providing lubrication, which helps to keep the skin moisturized and prevents it from becoming dry, flaky, or irritated. Sebum also has protective qualities, forming a barrier that can help shield the skin from environmental factors and pathogens.

In contrast, collagen is a structural protein that provides strength and elasticity to the skin, while keratin is a fibrous protein that aids in the formation of hair and nails and also provides a protective barrier on the skin's surface. Melanin is a pigment responsible for skin color and provides some protection against UV radiation, but it does not have a lubricating effect on the skin. Thus, sebum is uniquely suited for lubricating and protecting the skin compared to these other substances.