Half-Life
Also known as: t1/2 · elimination half-life
The time for a compound’s concentration to fall by half — a key determinant of dosing frequency in research.
Half-life (t½) is the time it takes for the concentration of a compound to fall to half its value. It reflects how quickly a molecule is broken down and cleared, and it governs how often a compound must be administered in a research protocol to maintain a given level.
Native peptides often have very short half-lives — minutes — because enzymes rapidly cleave peptide bonds. This is precisely why many research peptides are engineered analogs with modifications (e.g. terminal protecting groups) that extend half-life.
A short half-life is not necessarily a drawback; some pulsatile signalling (as with GH secretagogues) is studied specifically because the effect is brief and physiological.
RELATED TERMS
Analog
A peptide deliberately modified from a natural sequence to improve stability, selectivity or potency.
Peptide Bond
The covalent amide bond linking amino acids into a peptide chain — the defining structural feature of every peptide.
Secretagogue
A substance that prompts a gland to secrete a hormone — e.g. a GH secretagogue triggers the pituitary to release growth hormone.
Amino-Acid Sequence
The specific order of amino-acid residues in a peptide — its "primary structure" — which dictates shape and activity.
Educational content, not medical advice. All products supplied for research purposes only — not for human consumption.