Peptide vendors that closed, and how to choose your next supplier

Which peptide vendors closed, and what happened?

Think of it like a favorite restaurant closing. You would not pick the next place by its sign; you would look at the kitchen's inspection record. With a supplier, that record is a lot-specific certificate you can confirm with the lab that issued it.

Between the middle of 2025 and the middle of 2026 the research peptide market lost most of its best-known names. Published reporting counts at least nine: Peptide Sciences, Amino Asylum, Paradigm Peptides, Science.bio, Royal Research, Peptide Tech Labs, American Research Labs, Unchained Compounds and Strate Labs.

Two of those mattered more than the rest. Amino Asylum's warehouse in Memphis was raided by the FDA in June 2025 and the site went offline within days. Peptide Sciences, the largest of them, posted a three-sentence notice on March 6, 2026 and stopped taking orders. It gave no explanation, no timeline, and has said nothing since. There is no public information about whether it intends to return.

Reporting attributes the wave to about eighteen months of escalating federal enforcement: warning letters, physical raids, and legislative attention to the research-use-only framework the whole category is built on. If you buy in this market, read that last part carefully. The pressure is on the legal structure itself, not only on individual sellers, and a supplier that looks stable today is not necessarily insulated from it.

We are a supplier writing about competitors closing, so treat the framing with the suspicion it deserves and check the reporting at the bottom of this page. What follows is not an argument that you should buy from us. It is the set of checks that would have distinguished the operations that survived from the ones that did not, applied to us as much as to anyone.

Why does a supplier closing hurt more than losing a website?

Replacing a vendor is not the same as replacing a shop. Three things usually vanish at once.

The documentation goes first. If your certificates of analysis lived on the seller's site, they are gone when the site is. Anything you recorded against those lots (a purity figure, a method, a run date) is now a number in your notes with nothing behind it. If a certificate cannot be re-verified at the laboratory that issued it, it was only ever as durable as the seller's hosting bill.

The lot history goes with it. The reason to buy repeatedly from one supplier is that you accumulate a record: this compound, this lot, this measured content, behaved this way. A new supplier resets that to zero, and the first lot from anyone is the one you know least about.

Money in flight is the immediate problem. Several of these closures were abrupt. Orders placed and paid for shortly before the notice went up were, by multiple accounts, not fulfilled. That is an argument for payment methods with some recourse and against wiring money to a new supplier on a first order, whatever the discount.

Which checks would have warned you in advance?

None of these predict enforcement. What they do is separate operations that can survive scrutiny from ones that cannot, which turns out to correlate.

Are certificates lot-specific, and can you verify them somewhere else? This is the single most useful question. A certificate published as a PDF on the seller's own site, with no lot number, no method, no issuing laboratory you can contact, is a design element. The test is whether you can take the lot number to the laboratory that issued the report and confirm it independently. A seller who cannot offer that is asking you to trust their file management.

Does the certificate report identity, purity and net content as three separate measurements? They answer different questions and one cannot substitute for another. Identity says the vial holds the compound named. Purity says what share of the material is that compound. Net content says how many milligrams of peptide are there, which differs from the gross fill because a lyophilized solid carries counterion and residual water. A lot can be 99% pure and still hold considerably less peptide than the label implies, with no contradiction. Our certificates page works through how to read each one.

Is a blanket purity claim doing the work of a measurement? A site-wide "99%+ purity" banner is marketing. It describes no particular vial. What matters is the figure on the certificate for the lot in your hand, and whether the method is named alongside it: column, gradient and detection wavelength for chromatography, and the instrument for mass spectrometry. A number with no method attached is not a result.

Where is the operation, and who is it? Domestic sourcing became a primary buying criterion after the raids, for practical reasons rather than patriotic ones: shorter transit, fewer customs variables, and an identifiable entity. A supplier with no address, no named people and no phone number has made a choice about accountability.

Does the seller tell you what it does not know? This one is unusual and it is the most informative. A record that says a field is pending, or that a compound's evidence base is thin, is a record maintained by someone who expects to be checked. Uniform confidence across a whole catalog is the tell.

What should you look for in a replacement supplier's catalog?

Two things are worth checking that buyers usually skip.

Blend composition. Blend names are not standardized. The same designation can mean different components at different ratios from one seller to the next, so a blend you reorder from a new supplier may not be the material you had. Ask for the per-component masses, and note that purity on a multi-component vial is uninterpretable without them.

Price per milligram, not price per vial. Across different fills, price per vial tells you almost nothing. A larger vial at a higher price is frequently cheaper per milligram, and net content shifts the real figure again once it is measured. Our cost-per-milligram tool does the comparison across sizes, and every product record here prints the per-milligram figure beside each size.

How should a first order with a new supplier go?

Treat a first order as a test of the supplier, not a restock. A few habits make that test worth something.

1. Order one vial of one compound you already know. Pick something you have bought before and have a record for. A compound you have never handled tells you nothing about the seller, because you cannot separate an unfamiliar material from an unreliable one.
2. Download the certificate before the vial arrives, and verify it independently. If the seller offers a laboratory verification link, use it and confirm the lot number matches. Do this while you still have a card dispute window open, not after.
3. Check the vial against the certificate on arrival. Lot number on the label against lot number on the report. Compound name, strength, and the research-use statement. A mismatch between the physical label and the paperwork is the single clearest signal to stop, and it is more common than it should be.
4. Keep your own copy of everything. Certificates, order confirmations, lot numbers, dates. The suppliers that closed took their documentation with them, and the buyers who kept local copies were the only ones who retained a usable record.

FOR LABORATORY AND IN-VITRO RESEARCH USE ONLY. Nothing here is a medicine, a supplement, or a treatment for anything, and none of it is for human or animal consumption.

What would we say about ourselves?

We are newer than the vendors that closed and we are not going to pretend otherwise. What we can point at is structural rather than reputational, because reputation takes years and we have not had them.

Every field on a product record renders only when it has been measured. Where a lot has not been tested yet, the page says so rather than showing a representative figure from a different batch. Certificates are searchable by lot, and each carries the issuing laboratory's own verification key so the report can be confirmed at source. The quality standard sets out what we test and what we do not, and the compliance page is explicit that nothing here is for human or animal use.

That is a description of a method, not a promise about the future. Apply the checks above to it.

Bottom line

At least nine research peptide vendors stopped trading between mid-2025 and mid-2026, and the pressure behind that wave is aimed at the research-use-only framework itself. A supplier that looks stable today can still close, and when it does, its certificates and your lot history can go with it.

So judge the next one on what you can check yourself. Look for lot-specific certificates you can confirm at the issuing laboratory, identity, purity and net content reported separately, a real address and named people, and a seller that says what it has not measured. Keep the first order small, pay with some recourse, and keep your own copies.

Common questions

Related guides: buying and vetting a supplier

• Wholesale peptides: 21 supplier checks before you wire anything
• Bulk peptide wholesale, and what changes when you buy at volume
• Buying peptides from China wholesale: a laboratory buyer's guide to price and paperwork
• Chinese Peptide Suppliers: How a Laboratory Evaluates One
• Peptide purity testing: what each fee buys and what it proves

Sources

• PeptideLaws, "Why Did Peptide Sciences Shut Down? Timeline, FDA Pressure, and What It Means for the Industry" 2026. Basis for the 6 March 2026 date, the three-sentence notice, and the characterization of the enforcement timeline. Trade reporting rather than a primary filing, which is why every claim drawn from it is attributed in the text rather than stated as established fact.
• The Peptide Catalog, "Peptide Vendors Shut Down 2025-2026: Who's Left" 2026. Basis for the list of nine closures and for the Amino Asylum raid in June 2025. Cross-checked against the PeptideLaws account above; where the two disagreed on detail, neither figure was used.
• PeptidesExplorer, "Is Peptide Sciences Coming Back?" 2026. Basis for the statement that no public information exists about a return, and that the company has issued no further communication.
• USP General Chapter <621>, Chromatography. Basis for the point that a purity result is only interpretable alongside its method — column, gradient and detection wavelength — rather than as a bare number.