Buyer's guide · Supplier due diligence
How to vet a peptide or API supplier before you buy.
If you source active pharmaceutical ingredients for a compounding pharmacy, outsourcing facility, or manufacturing program, your supplier's shortcuts become your compliance problem. Here is a practical checklist for telling a rigorous supplier from a gray-market one — and what documentation to demand before a single lot ships.
Why supplier due diligence is on you
When an ingredient comes in your door, its history becomes your responsibility. If a state board inspector or the FDA asks where a compound came from, how it was tested, and how it was handled, "our supplier said it was fine" is not an answer that protects your license. The gray market survives because buyers under pressure skip the verification step. The purpose of this checklist is to make that step fast and repeatable.
1. Registration & licensing
- Is the manufacturing facility FDA-registered, and will the supplier tell you which facility and its registration status?
- Does the supplier verify your license or registration before selling? A supplier that sells to anyone is a supplier that sells to everyone — including buyers who will draw regulatory attention to the whole chain.
- Can they explain how a given ingredient may lawfully be supplied for your use and jurisdiction?
2. Testing & certificates of analysis
- Does every lot ship with a lot-specific certificate of analysis (COA) — not a generic or reused document?
- Does the COA document identity and purity, with the testing methods stated?
- Is independent third-party testing available on request when your program requires it?
3. Documentation & traceability
- Can every unit be traced to its manufacturing lot, and every lot to its source facility?
- Are storage and handling conditions documented, including cold-chain records where required?
- Is the paperwork organized the way your quality unit and inspectors expect to see it — audit-ready on arrival, not "available later"?
4. Transparency & references
- Do they answer direct questions about sourcing and testing with specifics, or with brochure language?
- Will they say no when something you ask for cannot be supplied lawfully? A supplier who never declines anything is not doing the checking.
- Can they speak to how they handle a change in a source's regulatory standing?
Red flags of a gray-market supplier
- No COA, or the same COA reused across lots.
- Won't name or won't verify the manufacturing source's FDA registration.
- Sells to anyone, with no licensure check.
- Public price lists and open carts for active pharmaceutical ingredients.
- Vague answers, pressure to buy quickly, or reluctance to put anything in writing.
If your current supplier can't check these boxes
That's exactly the gap PepDex Bio was built to fill. We supply vetted, FDA-registered peptide and pharmaceutical ingredients to licensed pharmacies, outsourcing facilities, and manufacturers — with a certificate of analysis and full lot traceability on every order, and licensure verified on every account. If you're re-evaluating a source, request access and put us to the test on a single line.
Source from a supply chain that passes its own checklist.
Tell us what you source today and what's not working. We respond within one business day — verification and a documented alternative for licensed buyers, or a partner referral for everyone else.