A vendor shipped another vendor's product — normal or a red flag?

It's a sign you're buying at the reseller end of the market: one shop selling stock that another shop filled and labeled. On its own that doesn't prove a problem. What matters is whether anyone has tested that batch.

Three checks:

• Find the batch or lot number on the vial and look it up in the Peptide COA lookup.
• Open the lab tests for the compound, for example Retatrutide lab tests, and see whether a test for that batch is on file from either shop.
• If the vial has no batch number at all, treat any certificate you're sent as unverified. Red Flags in Peptide Certificates of Analysis (CoA) lists what else to look for.

The index records the shop that submitted each test, not who filled the vial, so it can't tell you whether shop A and shop B share a source. The batch number can.

If this happened to you, post the compound, both shops' names (no links) and the batch number.