Amino acid

Last updated August 2026

The building blocks of peptides and proteins. A peptide is a short chain of amino acids linked together; the specific sequence determines what the peptide does.

There are twenty standard amino acids, and a peptide's identity comes entirely from which ones appear and in what order. Swapping a single residue can alter stability, receptor binding, or half-life, which is how research analogs are engineered from a parent molecule. This is also why mass spectrometry on a certificate of analysis checks the molecular weight that the exact sequence predicts.

Educational reference only — not medical advice. Always follow the guidance of a qualified healthcare professional.