Short chains of amino acids (typically 2 – 50 residues) designed to act on specific receptors or pathways and produce a measurable physiological effect. Insulin is a peptide. So is glucagon, oxytocin, and the GLP-1 family. They sit between small-molecule drugs and full proteins in size and function.
Different from cosmetic peptides (Argireline, copper peptides for topical skincare) which act at the skin surface. Therapeutic peptides are administered systemically (subcutaneous, intramuscular, or nasal spray) and act throughout the body. The full 32-peptide library covers all categories.