Peptides are fragments of proteins that consist of two or more amino acids linked in a chain. When two amino acids are joined together by a single bond it is called a dipeptide. Three linked amino acids are a tripeptide, followed by tetrapeptides, etc. The feature that distinguishes peptides from proteins is their size: peptides typically contain approximately 50 or fewer amino acids, whereas proteins consist of one or more polypeptides (a long peptide chain).There are many different peptides used in skin care products that are each designed to target specific skin concerns. For example, many peptides function as messenger peptides because they send messages or signals to cells. Cells have the ability to communicate with each other to coordinate certain actions, which is known as cell-signaling. For instance, when collagen is degraded it produces peptides that signal skin cells to generate more collagen. Synthetic peptides, such as tripeptide-1 and palmitoyl pentapeptide, can mimic these naturally occurring peptides, thus causing your skin to “think” collagen is deteriorating. This results in new collagen production. Over time, increased collagen levels promotes firmer skin with less fine lines and wrinkles.