Hyaluronic Acid (Filler) in Winterthur Both collagen and hyaluronic acid are important components of the skin. They significantly contribute to elasticity and hydration of the skin. The aging process leads to a loss of these two important skin components and ultimately will cause sagging skin. After being injected into the skin, fillers create a cushion under wrinkles and thus have an immediately visible effect on the skin surface appearance. The stimulus of the injection itself and the injected product also promotes the formation of new collagen, a main component of the skin.