Collagen and gelatin are very different but similar. Collagen components impact structural (joint) support and come in several types. Gelatin is used to build food structure and softness and comes in several types. Collagen is found in the skin, bone and connective tissues of many species. Gelatin is a class of protein derived from collagen and is also found in the skin and bones of pigs, cattle and several fish. They have some similar origins but are different.
Supportive or softness — Collagen versus gelatin
Collagen should be just as commonly accepted as gelatin in the pet food ingredient approval arena.