Reference

Every word, in plain language

No reader should hit a wall on one word. Everything this site says in its own vocabulary, said again here for someone hearing it for the first time.

31 terms · 4 groups

The substances

What the things being sold actually are.

Peptide: A short chain of amino acids, the building blocks the body uses to make proteins. Insulin is a peptide; so is most of what this site covers. Made in a lab, sold as powder, and fragile enough that heat or rough handling can break it.
Amino acid: One of the twenty small molecules proteins are built from, the way an alphabet builds words. When an entry says a compound is 'five building blocks long', these are the blocks.
Research compound: The label under which all of this is sold: 'for research use only, not for human use'. It is a legal position, not a description — the vials ship in injection sizes, and everyone in the transaction knows where they are going. The label's real meaning is that nobody checked what is inside.
Grey market: The unregulated trade in unapproved compounds sold under research labels. Not the black market — the selling is mostly open, with websites and discount codes — but nothing about the product is verified by anyone with authority over it.
SARM: Selective androgen receptor modulator: a lab-made chemical designed to act like testosterone in muscle and bone while sparing other tissues. Not peptides — most are pills — and the selectivity is the sales pitch, not a settled fact. See the SARMs class entry.
Secretagogue: A substance that prompts a gland to release a hormone the body already makes, rather than supplying the hormone itself. It asks rather than supplies. Most 'growth hormone' compounds here are secretagogues, and the difference matters: the effect is capped by what your own gland can do.
Receptor: The docking point on a cell that a molecule has to latch onto to do anything at all. When an entry says no receptor has been identified — BPC-157, thirty years in — it means nobody can yet say how the compound would work, which is worth knowing before believing claims about what it does. See the BPC-157 card.
GLP-1: Glucagon-like peptide-1: a gut hormone that signals fullness and slows the stomach. The famous weight-loss drugs — semaglutide, tirzepatide — are lab-made molecules built on it. The approved pens are medicine; the grey-market vials of the same molecules are not. See the buyer's guide.
IGF-1: Insulin-like growth factor 1: a growth signal the liver releases, largely in response to growth hormone. Entries watch it because it is the blood marker that shows whether a growth-hormone compound actually did anything — and for several sold here, it did not move.

The vial and the needle

The practical words, where the costly mistakes live.

Vial: The small glass bottle the powder ships in. The number on it — 5 mg, 10 mg — is the total amount inside, not a dose. Vial sizes quietly shape the doses people take: several 'standard' doses in circulation are just convenient fractions of the bottle. See what circulates vs what was studied.
Bacteriostatic water: Sterile water with a small amount of benzyl alcohol, which stops bacteria growing in it. It is what the powder gets mixed with, and the preservative is why a mixed vial can be drawn from repeatedly over weeks instead of used at once.
Reconstitution: Mixing the powder with sterile water so it can be measured and injected. The arithmetic — how much water into how much powder, and what one syringe mark then contains — is where people get hurt, more often than by the compounds themselves. See the calculator.
Syringe units: The marks on an insulin syringe. 100 units is 1 millilitre, so a unit measures volume, not drug — how much compound is in one unit depends entirely on how the vial was mixed. Two people drawing 'ten units' from differently mixed vials are taking different doses.
Micrograms and milligrams: 1 milligram (mg) is 1,000 micrograms (mcg, sometimes written µg). This thousand-fold gap is the most dangerous confusion on this entire subject: misread it once and the dose is off by a factor of a thousand.
Route: How a substance gets in: under the skin (subcutaneous), into muscle (intramuscular), into a vein (intravenous), up the nose (intranasal), or swallowed. A study by one route says little about another — the entries flag this constantly, because much of what circulates is injected while the research went a different way.
Half-life: How long until half of a substance is gone from the body. It decides how often something would need dosing and how long effects could last. For many compounds here it has never been measured in a person — including some marketed specifically as 'long-acting'.
Bioavailability: The fraction of a dose that actually reaches the bloodstream. Injection is close to complete; swallowed peptides mostly get digested like food. It is the reason 'the same compound in capsules' is usually a different proposition entirely.
mg/kg and scaling: Animal doses are given per kilogram of animal, and converting them to humans is not simple multiplication — a mouse's metabolism runs far faster. The accepted conversion uses body surface area. When entries scale an animal dose, that is the method; when a vendor's number does not match any scaling, entries say so.

The paperwork

The documents that stand between a label and the truth.

Certificate of analysis (COA): A lab report for one specific batch, stating what testing found inside. It is the only evidence a label is telling the truth, and it only ever vouches for the batch it names. Reading one takes about two minutes to learn and is the single most protective skill a buyer can have. See how to read a COA.
HPLC: High-performance liquid chromatography: the standard purity test. The dissolved sample is pushed through a separating column, different molecules come out at different times, and the result is a chart of peaks — the named compound's peak against everything else's.
Purity: The percentage of the powder that is the named molecule, usually from HPLC. It says nothing about the amount — a 99% pure vial can still be underfilled — and nothing about the next batch. This site has also seen a vendor print a mass in milligrams under a column headed purity, so even the heading deserves a look. See the corrections log.
Endotoxin: Debris from dead bacteria that triggers fever and immune reactions when injected. A powder can be sterile — nothing living in it — and still carry endotoxins. It is a separate test on a COA, measured in endotoxin units, and its absence from a certificate is worth noticing.
Sterility: Free of living microbes. Necessary for anything injected, and not implied by purity: a chemically clean powder can still be contaminated. Sterility, purity and endotoxins are three different tests answering three different questions.
Approved, off-label, unapproved: Three different things. Approved: a regulator reviewed the evidence for a specific product at a specific dose for a specific use. Off-label: a clinician prescribes that approved product for something else — legal and common. Unapproved: never cleared for anything, which is where nearly everything on this site lives. 'The molecule is in an approved drug' does not make the vial approved.
FDA warning letter: A formal notice from the American regulator that it believes a company is breaking the rules — often for selling unapproved drugs as research chemicals. It is not a recall and not a study; what it tells you is that the agency looked. Entries cite these where they exist.

The studies

The words that decide how much a claim is worth.

Placebo: An inert treatment given so nobody knows who got the real thing. 'Placebo-controlled' means the drug had to beat it, which matters because injections plus expectation reliably produce effects on their own. A result without a placebo group has not cleared that bar.
Randomized controlled trial: People are assigned to drug or placebo by chance, so the groups start out alike and any difference at the end belongs to the drug. Randomization is what separates 'people who took X did better' from 'X worked' — without it, the kind of person who takes X is part of the result.
Phase 1, 2, 3: The ladder a drug climbs. Phase 1: small, mostly healthy volunteers, testing safety and dose. Phase 2: does it work at all, in hundreds. Phase 3: the large trials approval hangs on, in thousands. Where an entry says 'the trial topped out at 1 mg', the phase tells you how seriously to take the ceiling.
Trial registry: ClinicalTrials.gov and its NCT numbers, where studies are registered before they run. Registration is a plan, not a result — it proves someone filled in a form. This site found one registry record that was a clone of another drug's real trial, which is why entries treat an NCT number as a lead to check, never as evidence by itself. See the retatrutide card.
Endpoint: What a trial commits, in advance, to measure as its test of success. The commitment is the point: picking the winning measurement afterwards is how weak results get dressed up. When an entry notes a trial 'met one of three primary endpoints', that arithmetic is the honest score.
Systematic review: A study of studies with a stated search method, so you can check what it looked for and what it excluded. Different from a narrative review, where an author cites what supports the story. The strongest tier of evidence when the underlying trials are good — and no better than them when they are not.

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