Most of what separates one Canadian research peptide supplier from another is not visible on a product page. It is in the documents, and in whether the supplier can produce them on request without hesitation. This page sets out what to ask for, how to read what comes back, and what a certificate does not tell you — including the parts that are routinely misread in our favour and everyone else’s.
The documents behind a research peptide, and what each one establishes
Four documents sit behind a characterised peptide. Each answers a different question, and knowing which question each one answers is what makes a certificate readable rather than decorative.
- A certificate of analysis. Where it is lot-specific, it describes the material in your vial. Where it is representative — issued for one lot of a compound and published as the reference for that product — it describes what that compound looked like when it was characterised. Both are in common use across the industry; the batch number on the document is what tells you which you are reading.
- The chromatogram itself, not just the percentage extracted from it. A number without the trace behind it cannot be checked.
- The mass spectrum, with both the measured mass and the calculated mass for the sequence being claimed.
- The detection wavelength the purity figure was obtained at. This is printed on the chromatogram and it decides whether the figure means anything at all.
Every certificate we hold is published in full on the certificates of analysis page, reproduced as the laboratory issued it rather than summarised into a percentage. Publishing the document rather than a claim about the document is the part we think matters, and it is a fair thing to expect of anyone, ourselves included.
Third-party tested, in-house tested, and the difference that matters
“Third-party tested” is used loosely enough that it has stopped being informative on its own. The question it should answer is who selected the sample.
A laboratory reports on the material it was given. If the supplier chose which vial to submit, the report establishes that that vial met spec. It does not establish that the lot did. Independent sampling — where the testing party draws the sample — is a materially different claim, and almost nobody makes it explicitly, because almost nobody does it.
This is not a reason to dismiss supplier-submitted testing. It is the normal arrangement across the industry and the resulting data is real. It is a reason to understand what the document covers. Third-party versus in-house testing works through what changes between the two.
Why the detection wavelength decides whether a purity figure means anything
An HPLC purity figure is an area percentage: the main peak divided by the total area the detector recorded. What the detector can see is set by the wavelength.
At 214 nm or 220 nm the peptide bond itself absorbs, so every peptidic impurity in the sample is counted. At 280 nm only tryptophan, tyrosine and weakly phenylalanine absorb. On a sequence containing none of the three, a 280 nm purity figure is close to meaningless — the compound and most of its impurities are nearly invisible to the detector, and the resulting number flatters the material.
This is the single most useful line on a peptide certificate and the one most often skipped. If a supplier will not tell you the wavelength, the purity figure they are quoting cannot be interpreted. Reading an HPLC chromatogram covers what a shoulder on a main peak indicates, and why two certificates disagree covers how the same vial returns different figures at two laboratories without either being wrong.
What the milligram figure on the label refers to
To the mass of material in the vial: peptide, plus counter-ion, plus residual water. Not to the mass of peptide.
The counter-ion is part of the isolated salt and contributes real mass — TFA and acetate counter-ions covers what changes between the two forms. Residual water in a freeze-dried solid is commonly a few percent and is measured by Karl Fischer titration rather than assumed; water content in lyophilised peptides covers that measurement.
The figure that accounts for both is net peptide content, and it is the number most often missing from a certificate. A vial can honestly be 98% pure and 78% peptide at the same time, with both figures correct and neither misleading on its own. Net peptide content explained sets out the arithmetic. A supplier comparison run on purity alone, across vials with different salt forms and different water content, is not comparing like with like.
What a certificate of analysis does not establish
A routine identity and purity certificate is silent on sterility. It is silent on endotoxin. It says nothing about suitability for use in a person or an animal. Those are separate tests, they are not part of routine peptide characterisation, and their absence is not an oversight — they were not run.
Reading a purity figure as a safety statement is the most common misreading of these documents, and no supplier’s certificate supports that reading. Endotoxin, sterility and the limits of research grade is the longer version.
Buying from within Canada versus importing
The practical differences are customs, transit and recourse.
An imported order crosses a border, which means import processing, variable transit, and the possibility of a shipment being held or refused with no straightforward remedy. A domestic order does none of that. It also means the supplier is reachable under Canadian law and in your time zone, which matters more when something goes wrong than when it does not.
We ship domestically across Canada. Carrier and service are chosen at checkout — Canada Post, FedEx, Purolator or UPS, regular or express — orders are dispatched within one business day and typical transit is two to five days depending on destination. Orders over $200 ship free. Certificates are not shipped with orders; a vial is matched to its certificate by cap and crimp colour against the photographs on the report itself.
Where you are matters for transit rather than for what is available: the catalogue and the documentation are identical to every destination. Our research peptides Canada page covers the national picture, and each province and city page covers what shipping into that location involves.
Red flags when evaluating a supplier
- A purity figure with no chromatogram. The number cannot be checked and the wavelength is unstated.
- A certificate with no batch number, or a batch number that does not match the vial.
- A measured mass with no calculated mass to compare it against. The comparison is the identity check; one number alone is not.
- Language describing effects on a body, a dose, a route or a schedule. A supplier writing that way is not treating the material as research-use-only, whatever the disclaimer at the foot of the page says.
- A certificate presented as lot-specific when it is not. Publishing a representative certificate is ordinary practice; describing one as matching your vial when it does not is a different thing.
- No stated position on what happens if independent testing disagrees with the supplier’s certificate.
A pre-purchase checklist
- Is the certificate lot-specific or representative, and is it described accurately as whichever it is?
- Is the chromatogram published, not just the percentage?
- What wavelength was the purity figure obtained at?
- Is there a measured mass and a calculated mass, and do they correspond to the sequence claimed?
- Is net peptide content stated, or only purity?
- Is residual water measured or assumed?
- Does the supplier ship domestically, and what is the stated dispatch and transit time?
- What is the documented position if independent testing returns a different figure?
Frequently asked questions
Is it legal to buy research peptides in Canada?
Research peptides are supplied for laboratory research use only. They are not approved drugs, hold no Canadian market authorisation for human use, and are not sold for human or veterinary use. The purchaser is responsible for ensuring their intended laboratory use complies with the requirements of their own institution and with applicable law. We are not able to advise on the regulatory position of any particular research programme.
What purity should I expect?
Most research-grade peptides are supplied at 98% or above by HPLC area percentage. The figure is only interpretable alongside the detection wavelength and, ideally, net peptide content. A higher number obtained at 280 nm on a sequence with no aromatic residues is a weaker claim than a lower number obtained at 214 nm.
What is the difference between purity and net peptide content?
Purity describes the proportion of the peptidic material that is the target sequence. Net peptide content describes how much of the mass in the vial is peptide at all, after counter-ion and residual water are accounted for. They answer different questions and a certificate frequently reports only the first.
Why do two laboratories report different purity for the same vial?
Method differences — wavelength, column, gradient, mobile phase — change what the detector sees and how well impurities separate from the main peak. Both figures can be correct. This is covered in detail in why certificates of analysis disagree.
Does a certificate of analysis mean the material is sterile?
No. Sterility and endotoxin are separate tests that are not part of routine identity and purity characterisation. A certificate that does not report them is not implying they passed; it means they were not run.
Why buy from a Canadian supplier rather than importing?
Domestic orders do not cross a border, so there is no import processing and transit is more predictable. The supplier is also reachable under Canadian law, which matters when a shipment or a document is disputed.
All material is supplied for laboratory research use only. It is not a drug, not a supplement, and not for use in humans or animals.
