Collagen protein is obtained from the connective tissue of animals, for example from skin, bone or tendons, and is usually hydrolysed into an easily soluble powder. Unlike muscle protein, collagen consists to a large extent of the amino acids glycine, proline and hydroxyproline and does not contain all essential amino acids in sufficient amounts.
In practice, collagen powder is often promoted in connection with skin and joints. General, cautious statements are appropriate here, and individual effects cannot be promised across the board. Because of its incomplete amino acid pattern, collagen is not suitable as the sole protein source, and it complements an otherwise balanced protein intake rather than replacing it.
The Collagen guide offers a detailed overview, and the page Protein requirement explains how to put general protein needs into context.
