Glossary
Plain-language, one-line definitions of the terms used across this wiki. Educational only — see Disclaimer.
503A/503B — Two categories of U.S. compounding pharmacy: 503A makes patient-specific preparations from a prescription, while 503B outsourcing facilities make larger batches under tighter FDA oversight.
Amino acid — One of the small building-block molecules that link together in a chain to form peptides and proteins.
Anabolic — Promoting tissue building (e.g. muscle growth), as opposed to catabolic (tissue breakdown).
Bacteriostatic water — Sterile water containing ~0.9% benzyl alcohol to inhibit bacterial growth, commonly used to reconstitute lyophilized peptides; see Reconstitution & Dosing Math.
Bioregulator — A short peptide proposed to regulate tissue-specific gene activity; the term is used mainly in the longevity/peptide-bioregulator literature.
CoA — Certificate of Analysis; a lab document reporting a product’s identity, purity, and test results (often via HPLC and mass spectrometry).
Cycling — Running a compound for a set period then pausing, intended to limit tolerance, side effects, or downregulation.
Ghrelin mimetic — A compound that mimics ghrelin to stimulate growth hormone release (and often appetite); a type of secretagogue.
GHRH — Growth hormone–releasing hormone; the natural signal that prompts the pituitary to release GH (analogs include Sermorelin and Tesamorelin).
GHRP — Growth hormone–releasing peptide; a class of peptides that trigger GH release through the ghrelin receptor.
GLP-1 — Glucagon-like peptide-1, a gut hormone that lowers blood sugar and appetite; GLP-1 receptor agonists like Semaglutide mimic it.
Half-life — The approximate time for the amount of a compound in the blood to fall by half; a key driver of dosing frequency; see Half-Life & Pharmacokinetics.
HPLC — High-Performance Liquid Chromatography; a lab technique used to measure a peptide’s purity and concentration.
IGF-1 — Insulin-like Growth Factor 1; a hormone produced largely in the liver in response to GH, mediating many of GH’s growth effects.
Intramuscular (IM) — An injection delivered into muscle tissue, deeper than a subcutaneous injection.
Lyophilized — Freeze-dried into a stable powder; the form most peptides ship in, requiring reconstitution before use.
Mass spectrometry — A lab technique that identifies a molecule by its mass, used to confirm a peptide’s identity on a CoA.
Mcg vs mg — Micrograms versus milligrams: 1 mg = 1000 mcg; confusing the two is a dangerous 1000× dosing error.
Peptide — A short chain of amino acids linked by peptide bonds, generally smaller than a protein.
Pharmacokinetics — The study of how a compound is absorbed, distributed, metabolized, and eliminated by the body over time.
Reconstitution — Dissolving a lyophilized (powdered) peptide in liquid, usually bacteriostatic water, to make an injectable solution; see Reconstitution & Dosing Math.
RUO (research use only) — A label indicating a product is sold for laboratory research, not for human or veterinary use.
Secretagogue — A substance that causes another substance to be secreted, e.g. a GH secretagogue that prompts growth hormone release.
Subcutaneous (subQ) — An injection delivered into the fatty layer just under the skin.
Titration — Gradually adjusting a dose up (or down) over time, commonly to improve tolerability, as with GLP-1 agonists.
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