Glossary
The vocabulary, defined once
Why this existsMost confusion about peptides is vocabulary: a case series called a study, purity mistaken for safety, a topline result read as proof. 39 terms, each with a plain definition and a link to where it matters on LYO.
Reading a study
RCTRandomised controlled trial.PlaceboAn inactive comparator.Open-labelEveryone knows who got what.Case seriesA description of several patients, with no control group.Primary endpointThe one result a trial is designed to test.Effect sizeHow big the difference was, not whether it was statistically significant.Confidence intervalThe range the true effect plausibly lies in.Systematic reviewA search for every study on a question, with stated rules.Meta-analysisPooling the numbers from several trials.Phase 1, 2 and 3The stages of drug trials.Topline resultsHeadline numbers from a company, before peer review.Peer reviewIndependent scrutiny before publication.Evidence grade (A–D)LYO's rating of how much human evidence there is.
How the compounds work
PeptideA short chain of amino acids.Amino acidThe building block of peptides and proteins.LyophilizedFreeze-dried.GLP-1 receptor agonistA drug that mimics the gut hormone GLP-1.IncretinGut hormones that raise insulin after a meal.GIPGlucose-dependent insulinotropic polypeptide, the second incretin.Glucagon receptorThe third target in retatrutide.AmylinA pancreatic hormone that slows digestion and reduces appetite.Growth hormone secretagogueAnything that makes the pituitary release growth hormone.GHRHGrowth hormone-releasing hormone.GhrelinThe hunger hormone, whose receptor several peptides target.Melanocortin receptorsThe receptors behind tanning, appetite and sexual arousal peptides.Half-lifeHow long until half the drug is gone.BioavailabilityThe fraction of a dose that reaches the bloodstream.SubcutaneousInjected into the fat under the skin.HbA1cThree-month average blood glucose.MACEMajor adverse cardiovascular events.
Regulation and the market
Marketing authorisationRegulatory approval to sell a medicine.Off-labelPrescribing an approved medicine for an unapproved use.CompoundingPharmacy-made medicines for an individual prescription.Research use onlyA label, not a safety statement.COACertificate of analysis.PurityThe fraction of the powder that is the intended molecule.Schedule 4Prescription-only, in Australian law.WADA Prohibited ListThe substances banned in sport.How to cite LYOReuse is welcome; say where it came from.