A sample COA sold as the current lot
The lot number, dates or strength don’t match the quote. Ask which lot will ship and where its COA is. See current-batch COA.
SeqLine Bio · Supplier red flags
Buyer guide · warning signs
Peptide supplier red flags
Warning signs in documents, company details, payment and sales behavior. None proves a problem on its own. Each one is a reason to ask a specific question before you pay.
Documents
The COA doesn’t describe your lot.
Purity with no context
A purity figure with no specification, no MS identity result or no test date says little. Ask for the full COA. See how to read a COA.
One COA for every order
The same PDF across months and strengths is not tied to what ships. Ask for the COA that carries the lot number printed on your label.
Company
You can’t tell who the seller is.
A role that keeps changing
Manufacturer in one message, trader in the next. Ask for a written statement of the company’s role for your lot. See manufacturer vs reseller.
Names that don’t line up
The website, quotation, invoice and bank details carry different company names, with no written explanation of how they relate.
Certificates you can’t check
Quality-system or regulatory claims with no certificate number, issuing body, scope or entity name. Ask for the document and confirm it with the issuer.
Payment and sales
The deal is pushed faster than it can be checked.
Payment to a personal account
Or bank details that arrive only by chat, or change mid-order. Pay the contracting entity, or a payee authorized in writing before payment.
Pressure to skip testing
Discounts that expire today, or no way to buy a small quantity first. A supplier that stands by its lots will let you test one.
A price far below others
It can mean old stock, a different specification or mixed sources. Ask for the lot COA and production date before deciding.
Human-use or dosing advice
A research-use supplier that advises on human use is working outside its stated scope. Apply the same caution to its other claims.
What good looks like
Signs worth seeing.
SeqLine Bio publishes how it meets each of these on supplier verification. Hold us to the same list.
- The supplier states its role in writing
- One company name on website, quotation, invoice and bank account
- A COA for the lot that ships, with specification, result, MS identity and dates
- A small first order is possible
- Independent testing is welcome and quality-claim terms are written down
FAQ
Questions buyers ask.
Is a PDF COA proof that a supplier is genuine?
No. Anyone can produce a PDF. Check that its lot number matches your shipment and that the company on it matches the seller, and test the material yourself when the order matters.
What is the most serious red flag?
A request to pay a personal or unrelated account. Document problems can be cleared up by asking; money sent to the wrong payee is hard to recover.
What does a good sign look like?
Consistent company details, a COA for the lot that ships, a payee that matches the seller, a small first order and written quality-claim terms.
Next step
Send your compound list and document requirements.
We reply within 4 business hours with price, lead time and the COA for the lot you would receive.