Peptide Glossary

Amino acid

The building block of every peptide and protein; a peptide is a short chain of them joined by peptide bonds.

Angiogenesis

The growth of new blood vessels from existing ones; the best-supported mechanism behind BPC-157's healing findings.

Aseptic technique

The habits that keep a vial and syringe free of contamination: clean surface, swabbed stoppers, fresh needles, no touching sterile parts.

Bacteriostatic water

Sterile water with 0.9% benzyl alcohol, the standard diluent for multi-dose peptide vials because it inhibits bacterial growth.

Bioavailability

The fraction of an administered amount that reaches circulation unchanged; near-complete for injected peptides, near-zero for most taken orally.

Certificate of analysis (COA)

A lab document for one production lot stating identity, purity and other test results; ask for it, read it, match the lot number.

Cold chain

Keeping a peptide refrigerated from manufacture to use; brief excursions are tolerated lyophilised, not once reconstituted.

Concentration (mg/mL)

How much peptide is dissolved per volume of diluent; set by reconstitution, it converts syringe units into micrograms.

DIN (Drug Identification Number)

The eight-digit number Health Canada assigns to every authorised drug product; a compound without one has not been approved for sale as a medicine in Canada.

Disulfide bridge

A covalent bond between two cysteine residues that holds a peptide's shape; present in several profiled compounds and confirmed by mass spectrometry.

Drug affinity complex (DAC)

A reactive group added to CJC-1295 that bonds it to albumin in blood, stretching a thirty-minute half-life to about a week.

Endotoxin

Fragments of bacterial cell wall that cause fever if injected; tested by the LAL assay and reported in endotoxin units.

FDA 503A bulk substances list

The U.S. FDA's evaluation of substances pharmacies may compound; in 2023 it placed many research peptides in category 2, barring them from compounding.

Ghrelin receptor (GHS-R1a)

The receptor for the hunger hormone ghrelin; GHRP-6, GHRP-2 and ipamorelin release growth hormone by activating it.

GHRH (growth hormone-releasing hormone)

The hypothalamic hormone that tells the pituitary to release growth hormone; sermorelin, tesamorelin and CJC-1295 are its analogues.

GIP (glucose-dependent insulinotropic polypeptide)

The second incretin hormone; adding GIP activity to GLP-1 is what makes tirzepatide a dual agonist.

GLP-1 (glucagon-like peptide-1)

A gut hormone released after eating that boosts insulin, suppresses glucagon, slows gastric emptying and reduces appetite.

Growth hormone secretagogue (GHS)

Any compound that prompts the pituitary to release growth hormone, via either the GHRH receptor or the ghrelin receptor.

Half-life

The time for a compound's concentration in the body to fall by half; it sets how often a peptide was dosed in studies.

Health Canada

The federal department that authorises drugs for sale in Canada; research peptides fall under its rules without being approved by it.

HPLC (high-performance liquid chromatography)

The lab method that separates a peptide from its impurities and reports purity as a percentage; the number a COA leads with.

Incretin

Gut hormones, GLP-1 and GIP, that amplify insulin release after a meal; the basis of the semaglutide, tirzepatide and retatrutide class.

Insulin syringe units (U-100)

On a U-100 syringe, 100 units equals 1 mL, so each unit is 0.01 mL; how much peptide that holds depends on the concentration.

Intramuscular (IM) injection

Injection into muscle tissue; faster absorption than subcutaneous, used for a minority of peptides and for hCG in fertility practice.

Lyophilised (freeze-dried)

Freeze-dried powder: the stable form research peptides ship in, reconstituted with bacteriostatic water before use.

Mass spectrometry (MS)

Measures a molecule's mass precisely; used to confirm that the main HPLC peak is the intended peptide sequence.

Melanocortin receptors

A receptor family activated by α-MSH that governs pigmentation, appetite, inflammation and sexual function; the target of melanotan II, PT-141 and KPV.

Mitochondrial-derived peptide (MDP)

A small peptide encoded in mitochondrial DNA rather than the nucleus; MOTS-c is the best-studied example.

Nitric oxide (NO) system

A signalling gas that relaxes blood vessels and modulates inflammation; several BPC-157 findings run through it.

Peptide

A short chain of amino acids, usually fewer than fifty, joined by peptide bonds; longer chains are proteins.

Peptide bond

The amide link between two amino acids; the bond that peptide synthesis builds and that proteases break.

Pulsatile release

The body's natural pattern of releasing growth hormone in bursts, mainly during sleep; secretagogues preserve it and continuous exposure flattens it.

Receptor agonist

A molecule that binds a receptor and activates it, as the natural signal would; dual and triple agonists hit two or three receptors at once.

Reconstitution

Dissolving lyophilised peptide in a sterile diluent so it can be measured and drawn as a liquid.

Research use only (RUO)

The legal category for compounds sold for laboratory research, not for human or veterinary use; it is a condition of sale, not a quality grade.

Stacking

Studying or using two or more compounds together; the literature does this for complementary mechanisms, rarely with controlled data on the combination.

Sterile water for injection

Preservative-free sterile water; suitable for single-use reconstitution, not for a vial that will be drawn from over weeks.

Subcutaneous (SC) injection

Injection into the fat layer under the skin; the route used for nearly every peptide in the research literature.

Telomerase

The enzyme that rebuilds the protective ends of chromosomes; the claimed target of epithalon, on evidence that remains thin.

Titration (dose escalation)

Starting a compound at a low amount and stepping it up over weeks; how every incretin trial and approved product is dosed.

Trifluoroacetate (TFA) salt

The counter-ion left over from peptide purification; peptides are supplied as TFA or acetate salts, and the choice affects content by weight.

WADA Prohibited List

The World Anti-Doping Agency's annual list of substances banned in sport; most growth-hormone and repair peptides are prohibited at all times.