Pharmacology
Half-Life
Half-life is the time required for the concentration of a substance in the body to decrease by half, determining dosing frequency.
Detailed Explanation
Peptide half-lives vary enormously — from minutes (native GHRH, unmodified peptides) to days (CJC-1295 with DAC, Semaglutide with albumin binding). Modifications that extend half-life include: amino acid substitutions (D-amino acids resist enzymatic degradation), pegylation (PEG-MGF extends half-life from minutes to days), and fatty acid conjugation (Semaglutide achieves ~165-hour half-life). Longer half-lives enable less frequent dosing.