Glossary

Peptide terms, in plain English

Every acronym and bit of jargon you'll run into — reconstitution, COA, IGF-1, titration, and the rest — explained clearly.

Bacteriostatic waterBAC water
Sterile water containing 0.9% benzyl alcohol, which prevents bacterial growth so a reconstituted vial stays usable for ~28 days refrigerated. Use this — not plain sterile water — for multi-dose vials.
Certificate of AnalysisCOA
A lab document showing a batch's purity and identity. The single most important tool for verifying you got what you paid for.
Concentration
How much peptide is in each mL of solution (mcg/mL), set by the vial size and how much water you add. Determines how many units = your dose.
Cycle
A defined on-period of use (e.g., 8–12 weeks) often followed by a break, to maintain sensitivity and limit risk.
Endotoxin
Bacterial toxin measured in EU/mg. For anything injected, a COA should report endotoxin below 1 EU/mg.
GH secretagogue
Any compound that stimulates growth-hormone release (GHRHs, GHRPs, and oral MK-677).
GHRH
Growth-Hormone-Releasing Hormone. Analogues like CJC-1295, sermorelin, and tesamorelin prompt the body's own GH release.
GHRP
Growth-Hormone-Releasing Peptide (e.g., Ipamorelin, GHRP-2/6). Works through the ghrelin receptor; often stacked with a GHRH.
GIP
Glucose-dependent Insulinotropic Polypeptide — a second incretin hormone. Tirzepatide activates both GLP-1 and GIP receptors.
GLP-1
Glucagon-Like Peptide-1 — a gut hormone that reduces appetite and improves blood sugar. GLP-1 agonists (semaglutide, etc.) are the basis of modern weight-loss medicine.
Half-life
How long it takes for half a dose to clear the body. It drives how often you dose — short half-life means more frequent injections.
HPLC
High-Performance Liquid Chromatography — the standard test for peptide purity. A good COA shows the HPLC chromatogram, not just a percentage.
IGF-1
Insulin-like Growth Factor 1 — the downstream marker of GH activity. The key lab to confirm a GH peptide is working (and to catch excess).
Insulin syringe (U-100)
A fine syringe marked 0–100 units (1 mL). Standard for subcutaneous peptide dosing.
IntramuscularIM
An injection into muscle tissue, using a longer needle. Used for some peptides and certain preparations.
Intranasal
Administration as a nasal spray, absorbed through the nasal mucosa. Common for Semax, Selank, and some others.
Lipohypertrophy
Lumpy fat-tissue changes from repeatedly injecting the same spot. Prevented by rotating injection sites.
Loading dose
A higher initial dose (or frequency) at the start of a protocol — common with TB-500 — before dropping to maintenance.
Lyophilized
Freeze-dried. Peptides are shipped as a lyophilized powder for stability and reconstituted before use.
Mass spectrometry
A lab test that confirms a vial actually contains the peptide it claims (its identity/molecular weight). Purity is meaningless if the molecule is wrong.
Peptide
A short chain of amino acids — smaller than a protein — that acts as a signaling molecule in the body. Therapeutic peptides mimic or modulate these natural signals.
Reconstitution
Mixing freeze-dried (lyophilized) peptide powder with a liquid (usually bacteriostatic water) to make an injectable or usable solution.
Research use onlyRUO
A label meaning a compound has not been evaluated by the FDA for human use. Most research peptides are sold this way.
Stack
Using two or more peptides together for complementary effects (e.g., BPC-157 + TB-500 for healing).
SubcutaneousSubQ
An injection into the fatty layer just under the skin (e.g., abdomen, thigh). The most common route for most peptides.
Titration
Gradually increasing a dose over time to let the body adjust — essential for GLP-1s to manage nausea.
Units / IU
The markings on an insulin (U-100) syringe. 100 units = 1 mL. Dose calculators convert your mcg dose into the units to draw.