Peptides are short chains of amino acids. The most common peptide known is insulin, and others follow such as collagen, oxytocin, dopamine, serotonin— these are all peptides. They are the building blocks of proteins and play crucial roles in various biological functions. The human body naturally produces more than 7,000 known peptide types, directly influencing hormones, neurotransmitters, growth factors, and other types of signaling molecules that regulate physiological processes.