Collagen is a protein that contains long chain amino acids, capable of binding themselves together. Peptides have the same chemical structure as proteins, but are smaller in size. These mini-proteins (both natural and synthetic) are involved in a host of biological functions - neurotransmission, stress responses, cardiovascular function and immune system response. These molecules play an important role in cellular activity as they're able to send signals to our skin cells. For example, if skin collagen becomes damaged, it breaks down into peptides that then tell your skin it's been harmed and needs to produce more collagen.