A purity figure of ≥99% is often the first number a researcher notices when comparing research peptides, and it is an easy one to anchor on. Yet an HPLC percentage is a method output, not a full description of the vial in front of you. Where a purchase has to remain unambiguously research-use-only, that figure works best as a prompt for further questions: which batch, which document, which method, and which handling obligations follow the sale.
What the Percentage Describes — and What It Cannot Tell You
A purity percentage is a method output, not a product specification in the round. When an HPLC chromatogram is integrated, the principal peak is usually expressed as a share of total peak area. That number is relative. It depends on wavelength, gradient, integration settings and the reference materials used, and on its own it does not establish that the material is the compound named on the label. A result of ≥99% by area can sit alongside an identity question that has not yet been answered in the document a buyer is reading. The sensible first question is therefore not “is it 99%?” but “99% of what, measured how, and on which batch?”
The word typically deserves equal attention. Published site wording refers to peptides supplied at typically ≥99% purity by HPLC, with the exact figure stated on the CoA, while the homepage carries marketing lines such as “≥99% Verified Purity” and “Over 99.1% Purity”. Those are the shop’s published figures, not independently audited statistics, and they should be reconfirmed against the live site and, more importantly, against the certificate that accompanies the specific batch you receive. Typically describes a general pattern across stock; it is not a promise about the vial in your hand.
Three further gaps are worth naming. First, purity by HPLC is not identity confirmation; a competent CoA should pair the purity result with identity data rather than leave the reader to assume it. Second, a purity figure says nothing about heavy metals or endotoxin, which the shop describes as part of an expanded testing framework alongside certificate documentation — check whether such screening appears on your batch document or only in general site language. Third, purity is not sterility, and it is not suitability for any particular assay; that judgement belongs to the researcher who designed the study.
One practical detail also affects how you read the number. The FAQs state that all peptides contain trace amounts of mannitol, an excipient used to support lyophilisation, solubility and stability in storage. A ≥99% peptide figure therefore does not mean the vial is 100% peptide by mass. When calculating concentration for an in-vitro experiment, work from the actual contents and your own validated method, not from the headline percentage alone.
Documents to Confirm Before the Order Is Placed
Batch-level documentation should be the deciding factor, not a category-level claim. The shop states that a Certificate of Analysis is provided for every product, covering purity and identity by HPLC, and that compounds are produced by international partners using solid-phase peptide synthesis before final verification and quality checks in the UK. The homepage also lists “CoAs Janoshik Analytical Reports”. None of that removes the buyer’s job: open the CoA for the batch you are buying and read it as a scientist.
Ask whether the certificate matches the batch in hand, whether it is dated, which analytical method produced the purity figure, and whether identity and any contaminant screening are reported for that same material. Researchers reviewing the catalogue can Buy peptides only after moving from the listing to the individual product page and its associated certificate, rather than relying on the category description. The all-products listing is a starting point for laboratory sourcing, not a substitute for batch paperwork.
Pay particular attention to the Internal Test Reference (ITR) system described in the FAQs. Restocked products may carry the same ITR as earlier stock, and an ITR links to associated sample testing reports; it does not confirm that separate deliveries come from the same production lot or that each delivery has been independently tested in its own right. Vial cap colours and other packaging may vary between deliveries, and cap colour is not an indicator of identity, analytical quality or manufacturing origin. Labels use a SKU-and-expiry reference, for example BPC10-03/27, which links to the corresponding CoA. Quoting that reference when contacting the shop about documentation is the quickest route to a precise answer.
Finally, confirm what is not in the item. The shop states that it does not supply blended peptides and recommends purchasing individual compounds and combining them only within a controlled experimental design. If a listing appears to bundle compounds, clarify the position before payment, because the documentation will follow the vial, not the assumption.
Keeping the Purchase Clearly RUO: Labels, Storage and Fulfilment
Compliance language is part of the product, so confirm it before payment rather than after delivery. The shop states that products are labelled “For Research Use Only – Not for Human Consumption”, described as being in line with MHRA guidance; that is the shop’s stated position and not legal advice. The purchaser remains responsible for lawful use, safe handling, storage and disposal, and for compliance with relevant UK regulations including COSHH and laboratory safety standards, as well as for judging whether an item suits the intended research application. Every item in the catalogue — including preparation tools, storage containers and water grades — is not for human or veterinary use.
Storage expectations should be settled early. The site’s quick guide advises allowing vials to reach room temperature before opening, working in a clean environment, removing only the quantity required for the experiment, and storing lyophilised peptides at −20°C or below, sealed with desiccant and protected from moisture, heat and light. Repeated freeze–thaw cycles should be avoided. Reconstituted material is less stable and should be held at 2–8°C for short-term laboratory work. Any reconstitution discussion belongs strictly to in-vitro workflow — diluent volume and target concentration for an assay, calculated in advance. The shop’s reconstitution calculator is described for laboratory research use only and must not be used for human or veterinary dosing.
Fulfilment terms are worth reading while the basket is open. Published terms state that orders are dispatched the next working day via Royal Mail Tracked 24, which usually delivers the following working day as a carrier estimate rather than a guarantee, with a tracking number issued after dispatch. Because of the specialist and perishable nature of the goods, returns are not accepted once dispatched, with refunds limited to damage, incorrect supply or quality issues under the Refunds & Returns Policy. Payment is by Pay-By-Bank or Open Banking through providers such as Wallid, regulated by the FCA; the shop states that it does not accept card payments and does not store bank login details. Confirm each of these points at checkout, and confirm any purity claim at the batch CoA, before the purchase is finalised.
