What signals indicate a trustworthy vendor?

Look for verifiable signals, not vibes. The strongest is independent, batch-specific testing you can confirm yourself — a COA from a named third-party lab (e.g., Janoshik) with HPLC purity, mass-spec identity, and a unique key that checks out on the lab's own portal. Supporting signals: COAs published openly rather than "on request," batch/lot numbers that match the vial, recent test dates, a real business identity with reachable support, reversible payment options, and a track record across independent reputation sources. Negative signals: therapeutic or dosing claims (a compliance red flag for "research only" sellers), prices far below market, and crypto-only checkout. Treat these as objective signals to weigh — never a paid "seal of approval."