Each vendor gets a 0–10 quality score weighted heavily toward verifiable lab testing. Our rubric:

• 40% — Certificates of Analysis (COAs): named third-party lab (Janoshik, Vanguard, Colmaric, Freedom Diagnostics), batch-to-vial linkage, public on-site publication, breadth of testing (purity via HPLC, identity via MS, endotoxin, sterility, heavy metals), and independent verifiability.
• 20% — Community reputation: Trustpilot rating and review volume, Reddit/forum sentiment, and known red flags (scam reports, failed COAs, contamination).
• 20% — Transparency: physical address disclosed, company age, ownership, contact info, published return policy.
• 20% — Operations: shipping speed, customer service responsiveness, payment flexibility, functioning partner/affiliate infrastructure.

Vendors with no independent review footprint (e.g. TRS Research) are marked Unverified rather than rated. COA status is shown on every card — look for COA ✓ · 3rd-party as the strongest signal.