Reference
Glossary.
Peptide writing is dense with jargon — and jargon is where people get misled. Here are the 23 terms that run through this catalog and the regulatory debate around it, in plain language. Paired with how we grade.
Evidence & regulation
- FDA-approved
- The FDA reviewed the trials and cleared the drug for a specific use. The only status where “approved” means proven safe and effective for that indication.
- Off-label
- Using an approved drug for a purpose it wasn’t approved for. A clinician may legally prescribe this way, but the evidence for that specific use can be thin.
- Compounding (503A / 503B)
- Pharmacies mixing a drug to order — 503A is patient-specific, 503B is a larger “outsourcing facility.” Compounded is not FDA-approved; no agency verifies each batch.
- Category 2
- An FDA list flagging bulk substances with significant safety risks for compounding. Being on it is a caution; being removed from it is not an endorsement.
- 503A bulks list
- The FDA’s roster of bulk substances allowed in patient-specific compounding. Most gray-market peptides are not on it.
- PCAC
- Pharmacy Compounding Advisory Committee — the FDA panel that reviews whether a substance belongs on the compounding lists. “Pending PCAC” means undecided.
- Gray market
- Sold “for research use only” but used by people off-label. No regulatory oversight of identity, purity, or dose.
- WADA
- World Anti-Doping Agency, which lists substances banned in sport. Several tracked peptides are prohibited.
How peptides work
- Peptide
- A short chain of amino acids — smaller than a protein. A few compounds here (e.g. NAD+) aren’t true peptides; each monograph says so plainly.
- GLP-1 / GIP
- Incretin hormones that regulate blood sugar and appetite. GLP-1/GIP receptor agonists (semaglutide, tirzepatide) are the metabolic blockbusters.
- Incretin
- Gut hormones (GLP-1, GIP) released after eating that boost insulin and curb appetite. Stacking two incretin-class agents is flagged as additive “incretin load.”
- Secretagogue
- A compound that makes your body release more of its own hormone. GH secretagogues (sermorelin, ipamorelin) prompt natural growth-hormone release rather than injecting GH.
- Melanocortin
- A receptor system affecting pigmentation, appetite, and sexual function. PT-141 and melanotan are melanocortin agonists.
- IGF-1
- Insulin-like growth factor 1 — the downstream signal of growth hormone, often measured to gauge growth-hormone-axis activity.
- MACE
- Major Adverse Cardiovascular Events — heart attack, stroke, cardiovascular death. Trials like SELECT measured semaglutide’s reduction in MACE.
- Half-life
- How long until half a dose has cleared the body. It drives dosing frequency: a long half-life allows weekly dosing, a short one needs daily.
Dosing & handling
- Reconstitution
- Mixing a freeze-dried peptide vial with sterile water to make an injectable solution. The arithmetic here is where most overdoses happen.
- BAC water
- Bacteriostatic water — sterile water with 0.9% benzyl alcohol — which lets a reconstituted vial be used over multiple days without growing bacteria.
- Lyophilized
- Freeze-dried into a powder for shelf stability. It must be reconstituted before use.
- Titration
- Starting low and stepping the dose up over weeks to limit side effects — standard practice for GLP-1s.
- U-100 syringe
- An insulin syringe marked 0–100 “units,” where 100 units = 1 mL. Units measure volume, not drug amount.
- Units vs mg/mcg
- Syringe “units” are a volume on a U-100 syringe; mg/mcg is the actual drug mass. Confusing the two drives 5–1000× overdoses — always recompute with the reconstitution calculator on any monograph.
- Subcutaneous (SC)
- Injected into the fat just under the skin — the most common route for these peptides.
Not medical or legal advice. Definitions are educational. Regulatory terms move with the FDA docket — re-verify against primary sources before acting.