Answer: collagen

AnswerCrossword Clue
COLLAGENLip enhancer
COLLAGENTissue protein
COLLAGENIt might give you a fat lip
COLLAGENMost common protein in mammals
collagenany of a class of extracellular proteins abundant in higher animals, esp. in the skin, bone, cartilage, tendon, and teeth, forming strong insoluble fibers and serving as connective tissue between cells, yielding gelatin when denatured by boiling