Methodology
We score 14 weighted criteria. The formula and weights are public and applied equally to every vendor.
score = 100 × Σ(weight × points) ÷ Σ(weight of verified criteria)
Product quality vs Testing breadth. We separate MEASURED QUALITY (the purity level of your certificates) from BREADTH (how many tests you publish). A vendor with a single 99.7% certificate has top quality even if its breadth is low: we never penalise quality for having few tests.
What is test rigour?. Measured quality is not just the purity number: each value is weighted by the RIGOUR of the test. A 99.7% analysed by a recognised independent lab (e.g. Janoshik), verifiable on the lab's own domain and with a recent certificate, is worth more than the same 99.7% with no verifiable lab or a year old. So two vendors with the same purity can have different measured quality depending on trust in the analysis.
Why does no one reach 100?. No vendor can score 100 on any axis or overall: the ceiling is 95. There is always room to improve —more lots, more types of analysis, wider shipping coverage— and a comparison that hands out hundreds would not be demanding. 95 is the ceiling of excellent, not a closed goal.
Product quality (8 weight)
| Criterion | Weight | Evidence |
|---|---|---|
| Measured purity (from CoA) | 3 | Scores the LEVEL of purity on the certificate (e.g. 99.7% = top). Measures verified quality, not how many tests a vendor has: a single 99.7% CoA scores as high as many 99.7% CoAs. |
| Published batch-level testing | 2 | The certificate maps to a specific lot printed on the vial, not a generic product analysis. |
| Independent lab, verifiable at source | 2 | The signing lab is an independent third party (e.g. Janoshik) with a verification link on its own domain, impossible for the vendor to forge. |
| Analytical methods disclosed (HPLC/MS) | 1 | The CoA states the analytical methods: HPLC for purity and mass spectrometry for identity. |
Testing breadth (3 weight)
| Criterion | Weight | Evidence |
|---|---|---|
| Number of lots/products with a CoA | 1 | How many distinct lots or products have a public CoA. Measures QUANTITY of evidence, separate from quality. |
| Variety of analyses (purity, identity, metals, endotoxin) | 1 | How many types of analysis are published: purity, identity, heavy metals, endotoxin, sterility. |
| Batch-to-batch consistency | 1 | At least two coherent CoAs of the same product demonstrating batch-to-batch consistency. |
Service quality (8 weight)
| Criterion | Weight | Evidence |
|---|---|---|
| Refund / return policy | 2 | A clear, public refund or return policy exists. |
| Shipping transparency & reliability | 2 | Shipping is transparent and reliable: carrier, timelines, tracking and, where relevant, customs handling (DDP). |
| Complaint handling & recall | 2 | There is a complaints channel and, ideally, a documented product recall procedure. |
| Accessible support & contact | 1 | Accessible contact and support (email, phone, form, chat). |
| Reconstitution & storage guidance | 1 | Reconstitution and storage guidance is published. |
Accessibility & trust (5 weight)
| Criterion | Weight | Evidence |
|---|---|---|
| Shipping coverage (countries) | 2 | How many countries it ships to: all of the EU = high, several = medium, a single country = low. |
| Accessible payment methods | 1 | Accessible, reliable payments (card/recognised gateway). Crypto/transfer-only or opaque = low. |
| Site quality & professionalism | 1 | Functional, secure (HTTPS), professional site with a working checkout. Broken or amateur site = low. |
| Identifiable legal entity | 1 | Registered, identifiable company (number, address). A bare VAT or anonymity = low. |
Transparency (4 weight)
| Criterion | Weight | Evidence |
|---|---|---|
| Publishes CoAs | 2 | The vendor publishes certificates of analysis, not just claims to test. |
| Pre-purchase access without account | 1 | CoAs are viewable before purchase, with no account or sign-up. |
| CoA recency | 1 | Certificates are recent (under 3 months), not years old. |