PeptideTrust answers one narrow, checkable question: how openly does a vendor document third-party testing? We do not test products, judge purity, or make safety claims. We record whether the paperwork a buyer would want actually exists, is specific, and can be verified at the source.
How a score is calculated
Each vendor is scored against 10 criteria, each carrying a weight. A verified criterion earns points (1 for a clear yes, 0.5 for partial, 0 for no; enum criteria have their own point scale). The score and coverage are:
score = round(100 × Σ(weight × points) ÷ Σ(weight of verified criteria))
coverage = round(100 × Σ(verified weight) ÷ Σ(total weight))
Crucially, an unverified criterion is excluded from the score but still counts against coverage. This prevents a vendor from scoring 100 on the strength of two cherry-picked facts. When coverage falls below 50%, we label the score provisional.
The 10 criteria and their weights
| Criterion | Weight | What it checks |
|---|---|---|
| Publishes CoAs | 3 | At least one certificate of analysis is published on the vendor's own site. |
| Batch-level CoAs | 3 | CoAs are tied to a specific batch/lot number, not one generic certificate per product. |
| Third-party lab named | 2 | The lab that ran the analysis is named on the CoA. |
| Independent / accredited lab | 2 | The lab is independent of the vendor and/or accredited, or a recognised independent peptide lab. |
| CoA verifiable at source | 2 | The certificate can be authenticated on the lab's own site — and we actually tested it. |
| Identity + purity methods | 2 | Which methods appear on the CoAs (HPLC+MS > HPLC only > other > none). |
| Freshness of latest CoA | 2 | Date of the most recent CoA (<3 months > 3–12 months > >12 months > none). |
| Accessible before purchase | 2 | CoAs viewable with no account and no prior purchase. |
| Sterility / endotoxin data | 1 | Sterility or endotoxin (LAL) results published in addition to purity. |
| Complaints / recall handling | 1 | A public recall/complaint policy or documented handling of a disputed batch. |
Our evidence rules
- Every finding is dated and sourced. Each criterion on a vendor page links to the exact page or document we checked, with the date we checked it.
- We never mark "No" on suspicion. A criterion is only "No" when a document or page establishes it. If we could not verify, it is "Unverified" — which hurts coverage but is not treated as a failure.
- Conservative by default. Where a vendor markets a stronger claim than its published document proves (e.g. "LC-MS" but only an HPLC chromatogram is shown), we score what the document shows.
- Affiliation is irrelevant to the rubric. Affiliated and non-affiliated vendors are scored identically, and the board is ranked strictly by score.
What the score is not
A high score means a vendor is transparent, not that a product is pure, sterile, or safe. A low score often means we simply could not verify claims (many sites hide CoAs behind JavaScript, age-gates or Cloudflare) — not that the vendor is dishonest. Read the per-criterion notes, not just the number.