Glossary

RCT (randomized controlled trial) — the strongest human test: people are split at random between the drug and a dummy (placebo), so the result reflects the drug, not hope or bias.

Placebo-controlled — some participants get a fake version, so any effect can be measured against doing nothing.

Phase 1 / 2 / 3 — the stages of human testing; phase 1 checks safety in a few people, phase 3 tests whether it actually works in many. Most gray-market peptides never finish phase 2.

Preclinical — tested only in animals or cells; never shown to work in people.

Review — a summary of existing studies, not new evidence; how much it's worth depends on whether it's systematic or just narrative (below).

Meta-analysis — pools the numbers from many trials into one combined result; usually the strongest single read of the evidence.

Systematic review — a thorough, methodical search of all the studies on a question; the rigorous kind of review (often paired with a meta-analysis).

Narrative review — a hand-picked summary, not a methodical search; lower-rigor and easy to cherry-pick; common behind weak claims.

Endpoint — the result a trial is built to measure (e.g. weight lost). "Missed its primary endpoint" means the main result didn't pan out.

Off-label — a real drug used for something it wasn't approved for; the approval doesn't transfer to the new use.

HPLC — the lab test that measures how pure a sample is and how much of the actual drug it contains.

Mass spec — confirms a sample is really the molecule claimed, not a look-alike.

Endotoxin (LAL) — bacterial contamination; for anything injected, the one that can land you in the hospital. The LAL assay tests for it.

COA (certificate of analysis) — the lab document meant to back a purity claim; only meaningful if it's from an independent lab and tied to your batch.

Third-party testing — a test run by an independent lab, not the seller. A vendor's own "lab result" doesn't count.

Purity / identity / quantity — the three things a good test answers: is it pure, is it the right molecule, and is there as much as the label says.

API — active pharmaceutical ingredient; the actual drug in the vial, as opposed to filler, salt, or solvent.

GLP-1 / incretin — the gut-hormone pathway the proven weight and diabetes drugs (semaglutide, tirzepatide) work through.

Amylin — another appetite hormone; the next wave of obesity drugs (cagrilintide and others) target it.

Secretagogue — something that nudges the body to release more of its own hormone; GH secretagogues prompt growth-hormone release rather than supplying it.

Agonist — a molecule that switches a receptor on, mimicking the body's own signal.

HPTA — the feedback loop that controls your natural testosterone; taking testosterone from outside suppresses it, so the body makes less on its own.

Myostatin — a brake on muscle growth; "myostatin inhibitors" are marketed to release that brake (mostly unproven in people).

Bioregulator (Khavinson) — a family of very short Russian peptides sold for organ-specific "support"; evidence is largely preclinical or Russian-only.

MASH / NASH — fatty liver disease; a target for several of the newer metabolic drugs.

Gray market — sold outside the prescription system, usually labeled "research only," with no regulator checking what's in the vial.