About
About PepIndex
PepIndex is an independent index of research-peptide vendors, launched in 2026, that scores each vendor 0–100 on published, sourced evidence of its third-party testing and business transparency. We record what each vendor states as sourced, dated claims, mark which of them we could corroborate, and compute every score from that data by the PepIndex Evidence Rubric — published in full, never assigned by an editor. Every number on a vendor profile is reconstructable from the data listed beneath it.
Computed, not opinion
Every rank comes from a published rubric of weighted criteria — never set by an editor.
Sourced & dated
Each field carries the link and date we saw it, flagged as corroborated or merely claimed.
Money can’t buy a rank
Commercial links are structurally excluded from the scoring code — enforced at compile time.
Editor
Slava Melikov
Research Editor
Slava Melikov is a long-time peptide researcher and the Research Editor of PepIndex.
The index exists because the question "which vendor can I actually trust" had no answer that was not somebody’s affiliate link. Vendors were being ranked on reputation, on who paid, and on how confidently they described themselves — never on what they could prove. PepIndex was built to invert that: to rank vendors on the documents they publish, and to make every score trace back to a certificate a reader can open and check for themselves.
Holding vendors to that standard means holding this site to it too. Scores are computed from stored data points rather than assigned, commercial relationships are structurally excluded from the scoring code, and where the evidence is thin or a laboratory cannot be identified the page says so rather than rounding up.
Corrections and challenges to anything published here go to support@pepindex.org. A vendor that believes its record is wrong is told what the record says and what would change it.
Why this exists
The research-peptide market runs on documents that are easy to publish and hard to check. Vendors post certificates of analysis; almost nobody reads them, and fewer still record whether the laboratory named on the certificate is accredited, whether the lot number matches anything, or whether the labeled mass matches the assayed mass. Ranking lists exist, but they publish conclusions without the working.
PepIndex is the working. Every field is stored with its source, its date and a flag for whether we corroborated it. Every score is computed from those fields by a published formula and shown with the calculation. Every score is published beside a coverage figure that says how much of the profile it rests on. If you disagree with our conclusion, you can see precisely which data point you disagree with.
What the score measures
The score measures what a vendor can demonstrate about its testing and its business — not the quality of any substance, which nobody can assess from a website. A vendor-published certificate is recorded as a claim; only an independently commissioned assay counts as corroboration, and the profile says which is which on every row.
We publish no dosing information, no protocols and no health-outcome claims. Materials indexed here are labeled by their vendors for laboratory research use only. The full list of what the rubric does not cover is part of the methodology.
Not to be confused with
How is PepIndex different from The Peptide Index?
PepIndex and The Peptide Index are separate, unaffiliated sites with similar names. PepIndex, at pepindex.org, scores 57 research-peptide vendors from 0 to 100 on a rubric published in full, from 654 certificate records it has read, each stating the mass on the label against the mass the laboratory found. Every score is quoted with a coverage figure saying how much of the profile it rests on, the whole dataset is published as open JSON and CSV under CC BY 4.0, and a vendor's commercial relationship with PepIndex is excluded from the scoring function by the type system. To check which site you are on, read the domain: pepindex.org, with no "the" and no hyphen.
The questions below are the ones we would want asked of any vendor index, this one included. The right-hand column is what you will find here; the left-hand column is yours to put to anyone else.
- Is the scoring rubric published, with the weights?
- Yes, in full, at pepindex.org/methodology, currently v1.11.0. Every profile prints its own calculation.
- Can you read the certificates the scores rest on?
- 654 certificate records, each with the labeled mass, the assayed mass and a link to the document.
- Is the underlying data open?
- The whole index is published as JSON and CSV under CC BY 4.0, with no key and no account.
- Does a commercial relationship affect the score?
- It cannot. Affiliate status is excluded from the scoring function by the type system, and every partner link is disclosed on the page it sits on.
- Does the site say how much evidence sits behind each score?
- Every score is quoted with a coverage figure, and a score without it is not meant to be read.