About Peptiledger

Peptiledger is a reading site about peptide quality documents. It explains how to read a certificate of analysis, what an HPLC chromatogram and a mass spectrum each prove, how to arrange an independent test and read the resulting report, how to check whether a supplier is who it says it is, and what changes in due diligence when you buy from a manufacturer, a stockist or a reseller. It does not sell peptides, list prices, take orders or rank vendors.

Who maintains it

The site is maintained by Pepti, a peptide manufacturer in Guangzhou, China. Pepti pays for the domain and hosting and its staff write and review the guides. Pepti's commercial site is separate; it is linked from the maintainer line at the foot of each guide and nowhere else in the body text.

The reason a manufacturer maintains a site like this is practical. Pepti publishes its lot records in a public library at peptioem.com/coa, and the questions buyers ask about those records are the same questions they should ask about anyone's records. Writing the answers down once, with primary sources, is more useful than repeating them in chat.

How Pepti's records are used

Worked examples use Pepti lot records because they are public and can be opened by any reader. When a guide says "open the record and compare the lot code on the label", you can do exactly that. The same checks apply to any manufacturer that publishes lot-level documents. Where a guide describes something Pepti got wrong or could have done better, it says so; the registry's first entry is an example.

Three Pepti facts are quoted in the guides and are current as of the last review date in the review log:

• the public library listed 79 lot records on 19 October 2026, each with a PEP-format lot code, an HPLC purity result, an MS molecular-weight result and a QR code resolving to the record's canonical URL;
• the chromatographic purity results across those records ranged from 98.4% to 99.8% (one blend record reports a textual result rather than a percentage);
• one independent report, Janoshik Analytical task 210105 analyzed on 7 October 2026, reports 19.52 mg Retatrutide content and 99.837% purity for a single submitted 20 mg sample and names peptioem.com as client and manufacturer.

Those are statements about specific records and one sample. They are not claims about products or lots that were not tested.

What the site will not do

• It gives no administration, medical or veterinary information. The materials discussed are research-use materials and the guides are about documents, not use.
• It does not rank or recommend named vendors. Comparison guides describe what to measure, not who wins.
• It does not describe logistics or border formalities.
• It uses the term GMP only in the sense of how to verify someone else's GMP claim. Pepti makes no such claim on this site.
• It does not invent figures. Every number is either from a primary source linked in the references or from a public record you can open.

How the guides are kept current

Every guide lists its publication date and last review date. A review means each external reference was opened and still supports the sentence that cites it, figures from public records were re-read, and regulatory references were checked for newer revisions. Reviews are logged at /review-log. A guide may carry a year in its title only when the log shows a review in that year; the build script refuses to publish otherwise.

Editorial method

• Primary sources only in the reference lists: regulators (FDA, EMA, MHRA and others), ICH and pharmacopoeial texts, peer-reviewed open-access articles, laboratory and accreditation-body websites, public registries, and the public lot records themselves.
• Sources are opened and read, not cited from memory. Links that stop resolving are replaced or the sentence is removed.
• Plain language is preferred to jargon; the glossary defines the terms that cannot be avoided.
• Corrections are welcome and are recorded in the review log with the date they were applied. See contact.

Structured data and reuse

Pages carry schema.org markup (Article, FAQPage, BreadcrumbList, Dataset for the registry, DefinedTermSet for the glossary). Text may be quoted with a link to the source page. The registry is published under CC BY 4.0 as CSV and JSON.