The Supply Chain Glossary
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Key findings
- Federal regulation defines "batch" and "lot" as different things: a batch is one manufacturing run, and a lot can be the whole batch or only a specific portion of it, which is why a lot number on a certificate does not always identify everything that came off that run.
- A certificate of analysis proves what one document reports about one sample on one date. It does not prove the vial in a buyer's hand came from the lot the document names. That is a separate question, and this publication's own dossier record does hold certificates that do not reconcile with the issuing laboratory's own copy of the same report.
- "Fill variance," the gap between a labeled amount and the measured content on a certificate, runs in both directions across this ledger's own documented cases, sometimes on the same product line.
- Every term below is defined for what it tells a buyer about documentation and testing. None of it is written to cover a route, a schedule, or an amount to administer, and that exclusion is deliberate rather than an oversight.
These eight terms turn up on nearly every research peptide storefront read for this ledger, usually as a badge or a single line, rarely with the definition that would let a buyer judge whether the badge means anything. Each entry below states what the term is, then closes on the harder question: what it actually proves about a given vial, and what it leaves open.
Certificate of Analysis (COA)
A document a laboratory issues after testing a specific sample, reporting the methods used and the results obtained against stated specifications. This publication's guide to reading one covers the fields in detail.
Proves: that a named laboratory ran stated tests on a sample identified by a lot or batch reference, on the dates printed. Does not prove: that the vial a buyer receives came from that same lot, or that the copy of the document the buyer reads matches the record the issuing laboratory holds. Checking the certificate against the lab's own record speaks to the second of those and not to the first, and it is worth doing because the two copies do not always agree. Queried on 2026-08-26, SteriGenix's public verification database returned the chemically correct molecular formula for three Vici Peptides retatrutide lots, while the SteriGenix-issued PDFs served from Vici Peptides' own site printed a different, incorrect formula on all three. This publication's record does not establish where that divergence originated.
Batch and Lot
Federal drug manufacturing regulation, 21 CFR 210.3, defines these terms separately, and the difference is not cosmetic. A batch is "a specific quantity of a drug or other material that is intended to have uniform character and quality, within specified limits, and is produced according to a single manufacturing order during the same cycle of manufacture." A lot is "a batch, or a specific identified portion of a batch, having uniform character and quality within specified limits", and the same definition carries a second branch for a drug product made by continuous process, so a lot can be the entire batch or only a slice of it. A lot number, control number, or batch number is defined separately again, as "any distinctive combination of letters, numbers, or symbols, or any combination of them" from which the complete manufacture, processing, packing, holding, and distribution history of a batch or lot "can be determined."
Proves: that a numbered lot or batch reference, if it resolves at the laboratory that issued the certificate, ties a specific test result to a specific, traceable production event. Does not prove: that every unit sold under a product name shares that lot, or that a lot number printed on a vial matches the one on the certificate offered for it, which is exactly the seam a batch-specific certificate closes and a catalog-level one does not.
HPLC (High-Performance Liquid Chromatography)
A chromatographic method that separates the components of a sample by how long each takes to pass through a column, then measures the area under each resulting peak. This publication's explanation of HPLC purity covers what the resulting percentage actually measures.
Proves: what fraction of the detected peak area, under the one method and conditions used, is attributed to the compound of interest versus other detected peaks. Does not prove: the compound's identity by itself, since two different substances can share a similar retention time on a given column, and it says nothing about anything the method was not configured to detect. A purity figure printed with no method named is not checkable at all. This site's own build refuses one where it is written in a pattern the rule can match, which is not every way the figure can be written.
Mass Spectrometry
A technique that measures the mass-to-charge ratio of ionized molecular fragments, used to confirm that a sample's molecular weight and fragmentation pattern match what a given compound should produce. The identity-confirmation piece covers the mechanics.
Proves: the closest thing to an identity check a certificate can carry, meaning whether the sample's measured mass matches the mass expected for the sequence claimed, which is what catches a deletion sequence an HPLC purity figure would pass cleanly. Does not prove: purity by itself, and it does not prove concentration unless paired with a quantitative method. It also cannot separate two molecules built from the same atoms in a different order, because those weigh the same. HPLC and mass spectrometry answer different questions, and a certificate carrying only one has answered only half of what a buyer needs.
Lyophilization
Freeze-drying: a process that freezes a solution, then removes the water by sublimation under vacuum, leaving a dry solid cake. The storage-science piece covers what the process stabilizes and what it does not.
Proves: that the water which drives hydrolysis has been taken out, which the linked piece reports collapses molecular mobility and slows chemical degradation by orders of magnitude. Does not prove: any ambient holding window, a number the linked piece declines to state for any specific peptide because none of its sources reports one, and nothing about purity, identity, sterility, or how long the product was frozen, dried, or stored before or after the lyophilization step, none of which the appearance of the finished cake can show.
Fill Variance
The difference between the labeled amount of a compound in a vial and the amount a laboratory actually measures on the certificate for that lot, usually reported as a percentage of label claim.
Proves: whether a specific tested vial contained more, less, or the labeled amount of active compound on the date it was tested. Does not prove: that every other vial in the same lot matches, or that a large overage is a bonus rather than a manufacturing-consistency problem. This ledger's own dossier record shows the gap runs both directions in practice: Luxara Labs' certificates, read 2026-08-25, reported label accuracy of 103.2 percent on one retatrutide lot and 109.4 percent on another, both passing, while two other lots from the same vendor measured under label on the vendor's own copies of the certificates. Full Scale Peptides' certificate library, read the same week, showed net content diverging from label in both directions: of the 14 documents it indexed, eight ran over label, counting the retatrutide certificate at 13.85 mg on a vial sold as 10mg, and four ran under. Nothing on the retatrutide product page or on the certificate itself explained that overage.
ISO/IEC 17025 Accreditation
A laboratory accreditation standard, granted by an accreditation body for specific, named test methods listed on a public scope document rather than for the laboratory as a whole. The dedicated piece on this standard, and the certification claims decoder, cover how the scope limitation works in practice and how a reader checks it.
Proves: for a lab holding active accreditation on a scope that names the method actually used, that an outside body found the lab competent to run that specific test. Does not prove: anything about a method the scope does not list, and it proves nothing once a certificate has expired or lapsed. Of the 126 supplier records in this ledger, 48 mention the standard in some form, a figure the certification decoder piece above breaks down by what each mention actually claims.
Endotoxin Testing
An assay, typically the Limulus Amebocyte Lysate method, that measures bacterial endotoxin against a stated limit, reported in endotoxin units. The dedicated piece covers why the units printed on different certificates often cannot be compared to one another directly.
Proves: that a specific tested sample measured below a stated endotoxin limit, in whatever unit and method the certificate names. Does not prove: sterility, a separate test entirely, and it proves nothing when no figure is printed. The FAQ on Grey Research Peptides' quality and testing page, read 2026-08-25, described endotoxin testing as something a buyer must separately request beyond the standard certificate, while the same page listed endotoxin testing among the tests it called standard, and none of the 32 certificates pulled directly from its named laboratory carried an endotoxin line at all.
What this glossary leaves out, on purpose
Every entry above answers a documentation or testing question: what a document shows, what a method measures, what a standard covers. None of it answers how much of anything to use, on what schedule, by what route, or in what organism, and that is an editorial line rather than an oversight. A glossary that drifted into protocol or administration vocabulary would stop being a reference for evaluating paperwork and start being something else entirely, which is not what this publication publishes.
Limitations and open questions
Definitions here are general and describe the term as commonly used and, where a federal definition exists, as regulation states it; they are not a substitute for the specification a given laboratory or standards body applies to a particular test. The ledger examples cited describe specific, dated observations about named suppliers, not a claim about how those suppliers' documentation looks today. Terms not covered here, such as chromatographic purity's own narrower definition or specific pharmacopeial chapter numbers, are addressed in the linked pieces rather than repeated in a glossary entry that would only summarize them thinly.
A term on a certificate is a claim about what was checked. Whether it was checked correctly, and whether the vial in hand is the one the certificate describes, are two more questions entirely, and this glossary only answers the first.
Sources
21 CFR 210.3, the 2025 edition published at govinfo.gov, read 2026-09-18, for the definitions quoted above: batch at (b)(2), lot at (b)(10), and lot number, control number, or batch number at (b)(11). The remaining definitions describe general laboratory and manufacturing practice as covered in this publication's own linked pieces, each carrying its own sources and fetch dates. Supplier observations are this publication's own, from the dossier record in ledger/vendors.json: Vici Peptides and SteriGenix, both 2026-08-26; Luxara Labs and Grey Research Peptides, both 2026-08-25; and Full Scale Peptides, 2026-08-25. Vendors are named here, never linked, per site policy.
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