Five checks that tell you whether a peptide supplier is real

Nearly every listing leads with a purity figure — 98%, 99%, sometimes 99.9%. It is the single most quoted number in the category and the most widely misread.

Purity by HPLC describes composition: of the peptide material present, what fraction is the target sequence. It says nothing at all about how much material is present. A vial can be 99% pure and hold a fraction of the mass on the label, and every number on that certificate would still be accurate.

The figure that answers the question you're actually asking is net peptide content — the mass in the vial, measured separately. A supplier who reports one and not the other has told you about the part that is easy to be good at.

Most storefronts display one certificate per product. It sits on the page for a year while stock turns over several times. It is a graphic.

Analysis is performed on a batch. A certificate that does not name a lot, or that names a lot you will never receive, documents someone else's material.

The test is simple: find the lot number, then ask whether that specific lot has its own document. If the answer involves the word 'representative', you have your answer.

This is the check almost nothing survives, and it costs nothing to run.

A document that appears after the money moves is a receipt. A document you can pull up while you are still deciding is a record. The difference is entirely one of sequence, and the sequence is chosen deliberately.

If documentation is only available in the box, in a support ticket, or 'on request after ordering', the supplier has decided you should commit first.

Free-mail contact address. No registered entity anywhere on the site. Support that exists only on a messaging app. Payment routed through a personal transfer, or crypto with no alternative.

None of these is proof of anything on its own. Each one removes a route you would use if something went wrong — a chargeback, a company to write to, a name on a document.

Count how many are missing. That number is your actual recourse.

The most common way to look cheaper than the market is to sell a smaller vial at a smaller price. On a listing page, side by side, it reads as a discount.

Divide the price by the milligrams. The order of the results changes more often than people expect, and it changes most dramatically among the suppliers advertising hardest on price.