Buyer Guide• 6 min read
Where to Buy Research Peptides in the US (Buyer's Checklist)
The US research-peptide market is unregulated at the vendor level, which means quality varies enormously. This checklist captures what experienced labs evaluate before placing a first order with any new supplier.
Non-negotiables
- Third-party HPLC COA — signed, dated, lot-matched to the vial you receive
- Mass spec confirmation — proves the sequence is correct, not just clean
- US-based fulfillment — shorter transit, fewer customs interruptions, faster cold chain
- Clear research-use-only labeling — no implied human-use claims
- Lot traceability — the lot number on your vial appears on the COA
Strong signals of a serious supplier
- Published purity standard (e.g. ≥ 99 % HPLC) rather than vague 'pharmaceutical grade' language
- Same-day shipping cutoff with insulated packaging on temperature-sensitive compounds
- Real customer-service contact (named team, working email) — not just a chatbot
- Narrow catalog with a clear sourcing philosophy — broad 1,000-SKU vendors often resell unverified material
- Domain age and consistent branding — short-lived vendor sites are a churned-store warning sign
Red flags
- No COA on the product page, or COAs that all look like the same template
- Prices dramatically below market — often a sign of underdosed or impure material
- Vague country of origin or routed through unrelated jurisdictions
- Refusal to share batch numbers before purchase
- Marketing copy that crosses into therapeutic claims (a compliance issue and a quality signal)
Why we built Zerilyx
Zerilyx exists because we got tired of suppliers that hid the paperwork. Every compound ships with a signed third-party HPLC and mass-spec assay tied to the lot on your shelf. Same-day US shipping before 1 PM EST, no surprises.