What “dilution” looks like
- Potency below market norms but just inside a broad spec.
- Excipient fingerprint (e.g., maltodextrin) not declared but visible in chromatograms.
- Density/solubility changes vs. true material.
Quick check: ask for raw instrument output (chromatograms/spectra), not only summary values.
What “substitution” looks like
- Botanical swaps within a genus (cheaper chemotype).
- Synthetic analogs in place of natural actives.
- Incorrect salt forms (e.g., Mg chelates vs. oxide).
Quick check: require fit-for-purpose identity methods (e.g., DNA/barcoding for botanicals, chiral/marker testing for actives).
COA tampering patterns
- Cropped pages, inconsistent fonts, missing lab address/accreditation (ISO/IEC 17025).
- Stale report dates vs. harvest/manufacture dates.
- Same COA reused across lots.
Tip: keep a COA library and hash PDFs; duplicates across suppliers pop out fast.
Controls that actually work
- Approved methods table per ingredient (which identity/assay is acceptable).
- AQL sampling + periodic 3rd-party re-test for high-risk SKUs.
- Supplier scorecards: audit history, CAPAs closed, lot-to-lot variability.
Red flags at purchase
- Price >15–20% below your rolling average.
- Vendor pushes pre-paid only, won’t release full COA package.
- “Proprietary method” but no validation summary.
Templates you can copy
PO/Contract language (excerpt)
Supplier warrants identity and assay per attached specification. Buyer may verify with independent ISO/IEC 17025 lab; failures trigger full refund, return rights, and documented CAPA within 10 business days.
COA request checklist
- Method & instrument model
- LOD/LOQ & uncertainty
- Sample chain-of-custody
- Analyst name & lab accreditation