What Research Peptide Suppliers Actually Publish: 12 Sites, September 2026

What was surveyed, and how

Twelve direct-to-consumer research peptide suppliers — eight Canadian, four American — were read on 15 September 2026 the way a buyer reads them: the homepage and the most prominent product page, as served that day. Sites were drawn from the first two pages of Canadian search results for research peptide suppliers; custom-synthesis houses and reagent catalogues were excluded because they serve a different buyer and publish to a different standard.

Twelve criteria were recorded per site, each answering one question: is this published where a buyer can see it? Absence from the pages read was recorded as absence, and no inference was made about what a business does behind its site. A supplier that tests but does not publish scores the same as one that does not test, because from the buyer's side those two cases are indistinguishable.

Every positive result on the two most easily confused criteria — net peptide content and instructions for use — was re-checked by extracting the verbatim text behind it. That check overturned five results, all in the same direction: a vial's fill mass had been read as a per-use quantity, or a purity percentage had been read as net content. The figures below are the corrected ones. This catalogue is one of the twelve and is scored by the same rules, below.

The numbers

A purity figure is common. A purity figure with its method is not.

Ten of twelve sites publish a purity percentage. Only six put the method beside it on the page where the number appears. The other four figures travel alone — a percentage with nothing to say what instrument produced it, at what wavelength, or what it is a percentage of. As set out in the note on purity versus net peptide content elsewhere in this journal, a peak-area ratio at 214–220 nm and a mass fraction are different quantities that happen to share a percent sign, and a bare number does not say which one it is.

Fewer still — four of twelve — name an identity method on the product page. That is the more consequential gap. A purity figure describes how much of the sample is the main peak; it does not establish that the main peak is the molecule on the label. Eight sites publish a number for the first question and nothing for the second.

Nobody publishes net peptide content

Zero of twelve. This was the criterion most often misread during collection — four sites initially registered as publishing it, and in every case the underlying text turned out to be either a purity percentage or a vial's nominal fill mass. Once the verbatim text was checked, the count fell to none.

The absence is structural rather than careless. Net peptide content is measured by amino acid analysis or nitrogen determination, not by the chromatography that produces a purity figure, and it is the number that reveals how much of a vial's dry mass is counterion, water and salt rather than peptide. It is also the number least flattering to publish, which may be why an entire category has settled on not publishing it.

Reports exist more often than the labs that wrote them are named

Five sites publish a per-lot analytical report a buyer can open. Three name the laboratory. So two sites publish a document and decline to say who produced it, which leaves a reader with a report that cannot be verified against the issuer. One site names two independent laboratories and links a report from each per lot; one names an accredited laboratory and states the accreditation. Those two are the exceptions.

A named laboratory is not proof of anything on its own. It is the thing that makes proof possible, because a report from an unnamed source cannot be checked against that source.

Sterility: three claims, one method, one disclaimer

Three sites claim sterility or endotoxin testing. One of the three names the assay and states a numeric limit with its unit. The other two make the claim without saying how it was tested or to what threshold — which is a different kind of statement from the first, even though the words are similar.

One site states, in plain terms, that sterility and endotoxin testing are not performed and not claimed. That site is this one. It is recorded here as a data point rather than a virtue: an explicit limit is more useful to a buyer than silence, and eight of twelve sites are silent on the question either way.

What the category gets right

Eleven of twelve sites carry a research-use-only notice, and none of the twelve publishes instructions for use on the pages read. Whatever else varies, the classification is stated almost universally and the highest-risk category of content is absent. That is a materially cleaner position than the category held two years ago, and it is worth saying so.

Where this catalogue stands

Held to the same twelve criteria, this catalogue states a purity figure, discloses its analytical methods on the standards page and in this journal, carries a research-use-only notice, publishes no instructions for use, and states plainly what it does not test for: sterility and endotoxin are disclaimed rather than implied. The country statement is manufactured in North America and shipped from Ontario.

On the criteria the category most often fails, stating limits and omitting instructions for use, it is in the smaller group that passes. The documentation criteria are the ones every supplier, this one included, has the most room to build on, and the standards page is where any change to what is published will appear first.

What this survey does not establish

It does not establish what any supplier actually tests, only what each publishes. It does not verify a single published figure — a report being downloadable is not the same as a report being accurate, and this survey checked presence, not content. It surveyed twelve sites on one day, and a site can change what it publishes at any time. And it ranks nobody: the table reports counts across the category, and the only supplier described by name is the one publishing the survey.

It does establish one thing with some confidence: a buyer in this category is routinely shown a purity percentage, is shown the method behind it half the time, is shown who measured it a quarter of the time, and is never shown what fraction of the vial that percentage describes.