Agonist
A molecule that activates a receptor and produces a biological response — as GLP-1 agonists activate the GLP-1 receptor.
Amylin
A satiety hormone co-secreted with insulin by pancreatic beta cells; the target of cagrilintide.
Bioavailability
The fraction of an administered dose that reaches systemic circulation unchanged. Injection and oral routes differ enormously for peptides.
Blinding
Concealing group assignment from participants (and ideally investigators) so expectation cannot systematically bias reported outcomes.
Compounding
Pharmacist preparation of a medication not commercially available. Unregulated "compounded" peptides skip even pharmacy oversight.
Contraindication
A situation where a medicine should not be used because its risks clearly outweigh benefits.
Double-blind trial
Neither participants nor investigators know who receives active drug — the design that most reliably separates drug effect from expectation.
Evidence tier
This catalog’s grading of a compound’s evidence base: approved medicine, clinical-stage, preclinical, or minimal evidence.
GIP
Glucose-dependent insulinotropic polypeptide — an incretin hormone; the second target of tirzepatide.
GLP-1
Glucagon-like peptide-1 — the incretin hormone mimicked by the largest class of peptide medicines.
Glycemic control
Management of blood-glucose levels, typically measured by HbA1c in trials.
GHRH
Growth hormone releasing hormone — the hypothalamic hormone that stimulates GH release; the template for sermorelin and CJC-1295.
GHRP
Growth hormone releasing peptide — ghrelin-receptor agonist family including GHRP-2, GHRP-6, ipamorelin, and hexarelin.
Half-life
The time for plasma concentration of a compound to fall by half — the main determinant of dosing frequency.
Indication
The specific medical use a regulator has approved a medicine for. Off-label use is outside the indication.
Incretin
Gut hormones (GLP-1, GIP) released after meals that stimulate insulin secretion.
Lyophilized
Freeze-dried. Most research peptides are shipped as lyophilized powders for later reconstitution.
Pharmacovigilance
The monitoring system that collects adverse-event reports for approved medicines. Research chemicals have none.
Placebo
An inert comparator that controls for expectation effects — essential when outcomes are subjective.
Preclinical
Studies in cells or animals, before human testing. Necessary, but historically poor at predicting human outcomes.
Randomized trial
A study where chance assigns treatment — the design that controls for confounding most effectively.
Reconstitution
Dissolving a lyophilized powder in diluent (e.g., bacteriostatic water) before use.
Research Use Only
A labeling category meaning a product is not for human use; it carries no quality guarantees for human administration.
Secretagogue
A substance that stimulates secretion of another hormone — as GH secretagogues stimulate growth hormone release.
Somatostatin
The hypothalamic hormone that inhibits GH release; part of the feedback loop secretagogues interact with.
Tolerability
How acceptable a medicine’s side effects are at effective doses — distinct from safety, which includes rare serious risks.
WADA
The World Anti-Doping Agency, whose Prohibited List governs sport testing worldwide.
Evidence tier: Approved medicine · Last reviewed: 2026-09-05 · Sources cited below.