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How to Choose a Peptide Vendor: A Researcher's Checklist

Practical criteria for evaluating peptide suppliers — from COA quality to shipping reliability and community reputation.

DEM

Dr. Elena Marsh

Chief Science Officer

March 10, 2026

Before You Order

Choosing a peptide vendor is a critical decision that directly impacts your research quality. Here's what to evaluate:

The Checklist

✅ 1. COA Quality

  • Does the vendor provide a COA for every batch?
  • Does the COA include both HPLC purity and mass spec data?
  • Is the COA from an accredited lab?

✅ 2. Purity Standards

  • Is the stated purity ≥ 95% for research grade?
  • Are purity claims supported by chromatogram data?

✅ 3. Third-Party Verification

  • Is the vendor listed and verified on PepAssure?
  • What is their PVS score?

✅ 4. Community Reputation

  • Check r/Peptides and related forums
  • Look for consistent positive feedback over time
  • Be wary of vendors with only recent, suspiciously positive reviews

✅ 5. Transparency

  • Clear contact information and business address
  • Published return/refund policy
  • Responsive customer service

✅ 6. Shipping & Handling

  • Appropriate cold-chain shipping for temperature-sensitive peptides
  • Discrete packaging
  • Domestic vs. international shipping options

✅ 7. Pricing

  • Competitive but not suspiciously cheap
  • Bulk pricing available
  • Clear pricing without hidden fees

Red Flags

  • ❌ No COA available or "COA available upon request" only
  • ❌ Identical COAs across different peptides or batches
  • ❌ No verifiable business information
  • ❌ Prices significantly below market average
  • ❌ Aggressive marketing with medical claims

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