Tripeptide

A short-chain peptide composed of exactly three amino acids linked by peptide bonds. Glutathione (gamma-L-glutamyl-L-cysteinyl-glycine) is the most biologically significant tripeptide in supplement formulation — the "master antioxidant" (Section 50). Contrast with dipeptide (two amino acids), oligopeptide (3–20 amino acids), polypeptide (21 or more amino acids), and protein (large polypeptides, typically >50 amino acids).