Collagen is a type of fibrous protein arranged in a triple helix pattern and found extensively throughout the bodies of people and animals. It supports skin, internal organs, muscles, bone, joints, and cartilage. There are at least 16 types of collagen that occur naturally in the body, with the most abundant form in the human body being known as type 1 collagen. Collagen works in tandem with elastin to give skin its texture, structure, ability to stretch, and appearance. Sun damage (extrinsic aging) and chronologic aging (intrinsic aging) causes collagen in the skin to deteriorate (Sources Journal of the American Academy of Dermatology, December 2013, ePublication; PLoS One, August 2013, eCollection; and Molecular Cell Biology, 4th Edition, W.H. Freeman, 2000).
As a cosmetic ingredient, collagen is derived from animal sources, but plant derivatives that act like collagen (pseudo-collagen) and amino acid fragments of collagen such as hydroxyproline are also used. In any form, collagen is a good water-binding agent. Collagen in cosmetics, regardless of the source, has never been shown to have a direct effect on producing or building collagen in skin.