Many of our clients ask us a lot of questions relating to skin firmness: collagen, elastin, skin tightness, skin elasticity, collagen powders, skin tightening treatments and creams, how to increase skin elasticity, and of course, cellulite. Here is a concise guide on collagen, elastin and how these proteins affect skin firmness, elasticity and cellulite. Skin is made primarily of rigid protein-based fibres such as collagen and fibronectin and elastic protein-based fibres, such as elastin and fibrillin. Collagen and fibronectin give firmness/tightness to skin and other tissues, while elastin and fibrillin provide elasticity.