Collagen is the most abundant protein in the body and is a key constituent of all connective tissues. Collagen provides the infrastructure of the musculoskeletal system, essential for mobility. The intake of collagen ensures the cohesion, elasticity and regeneration of skin, hair, tendon, cartilage, bones and joints.hreonine is an essential amino acid for collagen production. Collagen is an important building block for the skin. It makes up to 30% of the protein of the living body and 70% of the protein that makes up skin. Collagen ensues the cohesion, elasticity and regeneration of skin.