SkinPlus Hyal is pure hyaluronic acid using the patented MCL (Multistaged Cross Linking) technology (the method of preparation of the micro-gel beads using polysaccharides) to improve the cross-linking rate. Without any additives since Feb. 2006 (upgraded the cross-linking level to overcome the limitations of existing Hyaluronic Acid filler). It could be last up to five years.