For laboratory research purposes only. Not for human consumption. This article is written for researchers and procurement teams evaluating suppliers; it discusses sourcing and quality criteria, not how to use any compound.
In early March 2026, Peptide Sciences, a US vendor that had been one of the most recognisable names in the research-peptide market for over a decade, posted a brief notice confirming a voluntary decision to close all operations and discontinue the sale of all research products. For laboratories and procurement teams that had used it as a default reference point, the closure removed a familiar benchmark overnight and turned “where do we source from now?” into an open question.
This guide is about answering that question well. It is not a ranking of named vendors, and it deliberately avoids the head-to-head “best supplier” tables that circulate online, many of which mix unverifiable claims with affiliate incentives. Instead it sets out the criteria a research buyer can apply to any supplier, with a focus on the European market, where EU-domestic dispatch removes a layer of friction that intercontinental orders carry. Everything below is framed for laboratory procurement of materials supplied strictly for research purposes only.
What the Peptide Sciences Closure Actually Changed
The practical effect of the closure was not that research compounds became unavailable. It was that a known quantity disappeared. Buyers who had standardised on one vendor’s documentation, batch numbering, and turnaround now have to re-run their due diligence on a replacement. That is a healthy moment to formalise what “good” looks like, rather than simply migrating to whichever site ranks first in a search result.
It also sharpened a distinction that already existed: sourcing from within the European Union versus sourcing across borders. For a European laboratory, an EU-based supplier ships within the single market, while an intercontinental order adds customs handling, longer and less predictable transit, and the possibility of inspection or hold. When a vendor that many European buyers had used intercontinentally exits, the case for an EU-domestic supplier becomes more concrete.
The right response is a checklist, not a panic purchase. The rest of this guide is that checklist.
Criterion 1: The Certificate of Analysis Standard
A Certificate of Analysis (COA) is the central quality document in research-peptide procurement, and it is where evaluation should start. Its evidentiary value depends entirely on who produced it and what it covers, not on the fact that a “COA” exists somewhere on the page.
A COA worth relying on for research-grade material should include:
- HPLC purity (%): High-Performance Liquid Chromatography, with the chromatogram included rather than a bare percentage. For research-grade material, purity figures of 98% and above are the working expectation, and 99%+ is achievable and increasingly common among quality suppliers.
- Identity confirmation by mass spectrometry (MS): the observed molecular mass should match the theoretical mass of the named compound within standard instrument tolerance. HPLC tells you how pure the sample is; MS tells you whether it is the right molecule. Both matter.
- Lot/batch number that matches the vial. A COA from a different batch is not a COA for what you received. The number on the document and the number on the vial must be the same.
- An independent testing laboratory named on the report, with the lab’s identity, the test date, and a way to verify the result. “Contact us for the COA” with no document, or a percentage with no issuing lab, are both weak signals.
- No commercial relationship between the lab and the supply chain. The testing lab should not be owned by, operated by, or co-located with the manufacturer or vendor. Independence is the entire point of third-party testing.
Per-batch testing, not a one-time sample
A single historical COA proves that one batch was tested once. Synthesis quality can vary between production runs, so the stronger standard is a fresh third-party COA tied to the specific batch a buyer receives. When you evaluate a replacement supplier, ask whether testing is per-batch or whether a single old certificate is being reused across stock.
Independent verification
In the European research-peptide market, Janoshik Analytical (Prague, Czech Republic) has become the most widely used independent third-party testing laboratory. A useful property of this model is that results are issued by the lab directly and can be checked at the lab’s own verification page (janoshik.com/verify/, using the report’s task number and unique key) without going through the vendor. The principle holds beyond any one lab: prefer suppliers whose COAs can be checked at the source rather than only as a PDF the seller hosts.
Extended parameters, where the protocol demands them
Beyond HPLC purity and MS identity, some EU suppliers provide expanded testing: endotoxin (LAL assay), bioburden or microbial limits, heavy-metal screening, and residual-solvent analysis. These matter most for cell-culture and small-animal research, where contamination can confound results. If a protocol is sensitivity-limited, confirm which extended parameters are available before ordering rather than assuming they are included.
Criterion 2: EU-Domestic Shipping and Logistics
For a European laboratory, dispatch origin is a logistics and continuity question worth treating as a first-class criterion.
Shipments that move within the EU single market generally travel between member states without customs duties or routine import formalities (restricted, mislabelled, or unlawful goods can still be subject to control), which typically means shorter and more predictable transit, commonly a few business days to most of the bloc. Orders arriving from outside the EU add customs handling and the possibility of examination or hold, with correspondingly longer and more variable timelines.
When evaluating a replacement supplier, it is worth confirming:
- Dispatch origin: is stock held and shipped from within the EU, or is “EU shipping” really a re-route of an intercontinental order?
- A destination-specific timeline: a stated delivery window for your country, not a generic “EU” figure.
- Cold-appropriate packaging: lyophilised material in sealed glass vials, packed so that transit conditions do not compromise integrity.
- Continuity: a sufficiently stocked catalogue so that a repeat order for the same batch family is realistic, which matters for longitudinal study designs.
Criterion 3: Documentation, Labelling, and Procurement Fit
The third criterion is whether a supplier fits an institutional procurement process and labels material correctly for research use.
- Research-use labelling. Material and product pages should state clearly that the compound is supplied for research purposes only and is not for human or animal consumption. Labelling that drifts toward consumer or medicinal framing is a signal to look elsewhere.
- Commercial invoicing. A proper invoice for procurement records, with VAT-compliant billing for EU buyers, is necessary for institutional purchasing.
- Handling and storage information, such as laboratory storage guidance (for example, lyophilised material held cold long-term, protected from moisture and light) framed as handling protocol, not as use instructions.
- Responsive technical contact: a real channel for COA requests, batch queries, and re-test questions, with documents provided up front rather than promised after purchase.
Red Flags When Vetting a Replacement Supplier
A short list of signals that warrant caution. None of these is, on its own, proof of a problem, but several together are a reason to slow down:
- No COA, or a purity number with no issuing laboratory named. Independence and traceability are the whole value of third-party testing.
- A single old COA reused across all current stock rather than a certificate tied to the batch you will receive.
- A COA that cannot be verified at the source, such as a vendor-hosted PDF with no independent reference.
- Consumer or medicinal framing: language that implies human use, treatment, or outcomes. For a research supplier this is both a compliance signal and a quality signal.
- Brand names of authorised medicines used to describe research compounds. Some research compounds share an active-substance name with separately authorised medicines; a serious research supplier refers to the substance (the INN), not to a medicine’s brand, and makes no therapeutic claims.
- A site impersonating a closed or well-known vendor. After a high-profile closure, look-alike sites commonly appear; confirm you are dealing with an operating business with a verifiable identity before entering any payment details.
- Pressure tactics, such as countdown timers, “last batch ever,” or claims that cannot be checked. Research procurement should be evidence-led, not urgency-led.
How CertaPeptides Maps to These Criteria
CertaPeptides is operated by CERTALAB SRL, an EU-registered company, and is built around exactly the criteria above. We include this section so the standard is concrete, not as a comparison against any named vendor.
- COA standard. Every product carries a third-party Certificate of Analysis from Janoshik Analytical, reporting HPLC purity with the chromatogram and mass-spectrometry identity confirmation. The COA is posted on the product page rather than offered only on request.
- Per-batch testing. Testing is tied to the batch, so the certificate reflects the material in stock rather than a single historical sample. Independent reports can be checked at the source by their identifier.
- EU-domestic dispatch. Orders ship from within the EU, so deliveries to most of the bloc move through the single market without customs handling, and material is packed in sealed glass vials appropriate for transit.
- Documentation and labelling. All compounds are labelled and described for research purposes only, with no human-use or medicinal claims, and orders are invoiced for institutional procurement records.
The aim is not to be “the new default” by name recognition, but to be the supplier that holds up when a research buyer actually applies the checklist.
Key Questions to Ask Any Supplier Before Ordering
- Which independent laboratory performed the COA, and what batch number was tested?
- Is testing done per batch, and can I verify the report at the source by its identifier?
- Can you provide the full COA document, with the chromatogram and MS identity rather than only a purity figure, before I order?
- Where is stock dispatched from, and what is the expected delivery time to my country specifically?
- Are extended parameters (endotoxin, heavy metals, residual solvents) available if my protocol requires them?
- Is your packaging and documentation labelled for research use only, with no human-use language, and do you issue a VAT-compliant invoice?
Summary
The closure of a long-standing benchmark vendor in March 2026 is a prompt to formalise supplier due diligence rather than to migrate on reputation alone. The durable criteria are the same ones that mattered before: an independent, per-batch Certificate of Analysis with HPLC purity and MS identity that can be verified at the source; EU-domestic dispatch with destination-specific timelines for European laboratories; correct research-use labelling; and procurement-grade documentation. A supplier that meets those criteria transparently, with COAs you can check rather than claims you must trust, is the appropriate starting point for any research buyer re-evaluating their options. CertaPeptides is built to that standard, ships from within the EU, and supplies all compounds strictly for research purposes only.
This article is for research information purposes only. All compounds referenced are supplied exclusively as research chemicals for laboratory use, not as medicinal products, and are not intended for human or animal use. Some compounds named (for example semaglutide and tirzepatide) are active substances in separately authorised medicines; CertaPeptides supplies only research-grade chemicals and makes no therapeutic claims.