Glossary

Core peptide research terms, defined plainly.

Bioavailability: The fraction of an administered dose that reaches systemic circulation in active form. Most peptides have very low oral bioavailability because they are degraded in the gut, which is why injectable routes are common in research.
CAS number: A unique identifier assigned by the Chemical Abstracts Service to a specific chemical substance, used to unambiguously reference a compound across databases.
GHRH analog: A compound that mimics growth-hormone-releasing hormone, binding the GHRH receptor on the pituitary to stimulate the natural release of growth hormone.
GHRP (Growth Hormone Releasing Peptide): A ghrelin-mimetic peptide that acts on the GHS-R1a receptor to trigger growth hormone release through a pathway distinct from, and synergistic with, GHRH analogs.
Half-life: The time it takes for the concentration of a compound in circulation to fall by half. Short half-lives mean rapid clearance; engineered analogs often extend half-life to reduce dosing frequency.
Lyophilised: Freeze-dried. Most research peptides are shipped lyophilised because the dry powder is far more stable than a solution and tolerates shipping at ambient temperature.
Mitochondrial-derived peptide (MDP): A small peptide encoded within the mitochondrial genome, such as MOTS-c or Humanin, studied for roles in metabolism, stress resistance, and ageing.
Peptide: A short chain of amino acids linked by peptide bonds — longer than a single amino acid but shorter than a full protein (typically fewer than ~50 residues). Peptides act as signalling molecules throughout biology.
Reconstitution: The process of dissolving a lyophilised (freeze-dried) peptide powder into a liquid — typically bacteriostatic water — to prepare a research solution.
Secretagogue: A substance that causes another substance to be secreted. Growth hormone secretagogues prompt the body to release its own growth hormone rather than supplying it directly.