Somewhere between December 2024 and March 2025, officers at U.S. Customs and Border Protection’s Cincinnati port of entry started noticing a pattern in the international mail and express-consignment freight moving through one of the busiest package-processing hubs in the country. Cartons manifested as one thing kept turning out to contain something else — smaller parcels inside, each addressed to a different individual recipient across the United States. By the time CBP finished tallying the operation, officers had identified more than 300 master cartons concealing roughly 5,000 individual shipments of unapproved weight-loss peptides, all traced back to China.
This wasn’t a single seizure. It was a smuggling structure — bulk freight, mis-manifested to avoid scrutiny, broken down at the border into consumer-sized parcels the way a distributor breaks down a pallet into individual retail units. That structure is the part of the grey market most researchers never see: not the website, not the checkout page, but the logistics operation that gets an unregulated peptide from a lab in China into a mailbox in Ohio.
What Was Actually In the Boxes
CBP’s Cincinnati field office reported that the intercepted shipments included retatrutide, semaglutide, and tirzepatide — the three compounds driving most of the current GLP-1 research and commercial interest — alongside other peptides the FDA has flagged as unapproved, including MOTS-C, TB10 (TB-500), semax, and cagrilintide. In other words, this wasn’t a niche shipment of an obscure research chemical. It was, by CBP’s own description, a slice of the exact product category driving consumer demand right now, moving through the mail with none of the oversight that governs an FDA-approved GLP-1 prescription filled at a licensed pharmacy.
Cincinnati Port Director Eric Zizelman was direct about why that matters beyond the legal violation itself:
“Noncertified or unlicensed chemicals originating from other countries and shipped into the United States present a serious health risk to those who use them.”
— Eric Zizelman, CBP Port Director, Cincinnati
That’s the core problem with grey-market peptide sourcing that no amount of marketing copy can paper over: product manufactured in facilities with no FDA oversight, no mandatory GMP inspection, and no requirement to test for contamination before export. It isn’t that overseas manufacturing is automatically unsafe — it’s that when something goes wrong at that stage, there is no regulatory backstop between the manufacturing line and the buyer’s mailbox.
Congress Starts Asking the Manufacturers Directly
The customs side of this story is about interception. A separate and arguably more consequential development is about origin. In January 2026, Congressman Raja Krishnamoorthi, ranking member on the House Select Committee on the Chinese Communist Party, sent formal letters to three China-based biotechnology companies — Chinese Peptide Company, Hubei JXBio Biotech, and Fujian Genohope Biotech — demanding detailed information about how they manufacture, label, and export GLP-1 drugs and active pharmaceutical ingredients that may be entering the U.S. supply chain without safety oversight.
The letters cite hundreds of adverse-event reports already received by the FDA tied to illicit compounded GLP-1 products, and reference an FBI warning connecting fraudulent compounded weight-loss drugs to gastrointestinal disorders, nervous system disorders, cardiac disorders, psychiatric disorders, and death. Krishnamoorthi’s office has warned that the true scope of harm is likely underreported, since there is no requirement that adverse events from unapproved, informally sourced peptides get reported to anyone at all.
It’s worth being precise about what these letters are and are not. They are Congressional oversight correspondence — a request for information and a matter of public record — not a finding of wrongdoing against any of the three named companies. But the fact that a Congressional committee focused on the Chinese Communist Party is treating peptide API manufacturing as a national supply-chain and public-health issue, rather than a niche fitness-industry story, is itself a signal of where this is heading.
Why the Supply Side Matters More Than the Storefront
Most coverage of the peptide grey market, including our own, tends to focus on the vendor: the website, the checkout flow, the Certificate of Analysis. That’s the part a buyer interacts with directly, so it’s the part that gets scrutinized. But a vendor is often just the last link in a much longer chain, and the Cincinnati seizure is a useful reminder of what that chain actually looks like: unregulated manufacturing overseas, bulk export mis-manifested to clear customs, and a domestic operation that breaks the bulk shipment into individually addressed parcels before it ever reaches a “warehouse” a customer might picture when they think about where their order ships from.
That structure explains something researchers often find confusing: how a vendor with no obvious U.S. manufacturing footprint can offer same-week shipping on dozens of compounds. In many cases, the answer is that very little manufacturing or quality control is happening domestically at all — the product is imported in bulk, broken down, and relabeled here.
What This Means If You’re Evaluating a Vendor
None of this means every peptide sourced from an overseas manufacturer is unsafe, and it doesn’t mean every domestic-sounding vendor is legitimate. It does mean that “where does this actually come from, and who tested it before it got here” is a fair and increasingly urgent question, and that a vendor’s inability or unwillingness to answer it specifically — naming an actual manufacturing site, an actual independent testing lab, an actual batch record — is a meaningful red flag, not a technicality.
We cover how to evaluate that kind of claim in detail in our Vendor Guide, and we’re tracking the enforcement side of this story, including the federal case that sent a peptide vendor’s owner to prison for nearly six years, in our Grey Market Watch hub.
This article is based on public statements from U.S. Customs and Border Protection and the office of Rep. Raja Krishnamoorthi. No company named in the Congressional letters has been charged with or found to have committed wrongdoing based on the information in this article.