How to Tell if a Peptide Vendor Is Legit: 6 Checks

By Editorial team. Updated Oct 15, 2026. Awaiting editor sign-off

The research-peptide market changes quickly. Large vendors have closed, regulators have sent warning letters, and new storefronts appear every week (see our alerts tracker). You can’t lab-test every vendor yourself. You can, however, check the public facts in about 15 minutes. These are the same six checks behind our transparency checklist, and we list the results for each vendor on our vendor pages.

None of these checks tells you what is in a vial. They tell you how much a vendor is willing to show, and how much protection you have if something goes wrong. For lab evidence, see our guides to reading a COA and peptide testing.

Check 1: Domain age and history

Why it matters. A shop that registered its domain last month has no track record. Old domains can also be bought and repurposed, so look at the history as well as the age.

How to check.

1. Enter the domain in ICANN Lookup, which queries the official registration data (RDAP) [1]. Note the creation date, the registrar and the expiry date. Privacy-protected contact details are normal and aren’t a red flag on their own.
2. Enter the domain in the Wayback Machine [2]. Look at the year of the first capture and open a few snapshots across the years. You’re checking two things: was this always a peptide shop, and did the name or ownership change suddenly?

Red flags:

• A domain created in the past few months.
• A one-year registration on a “long-established” brand.
• A site that was something unrelated until recently.
• A domain that only resembles a closed vendor’s name.

Check 2: Public, batch-specific COAs

Why it matters. A certificate of analysis tied to a specific batch, posted where anyone can read it, is the strongest evidence a vendor can offer without an independent test.

How to check. Look for a COA library or a COA on each product page. A useful COA has a batch number that matches the label, a recent date, and identity, purity and quantity results. Then verify one directly with the lab (see how to verify a COA).

From best to worst: batch-specific COAs anyone can read; a generic “sample” COA reused across batches; COAs only “on request”; nothing at all.

Check 3: An independent lab is named

Why it matters. An in-house report is the vendor grading its own homework. A named third-party lab can be contacted and asked to confirm the report.

How to check. Find the lab’s name on the COA, then find the lab’s website yourself and use its verification route. If no lab is named, or the “lab” has no web presence, treat the COA as unverified.

Check 4: Company identity

Why it matters. A legal name and a physical address mean there is someone accountable. Anonymous storefronts can vanish overnight.

How to check.

1. Find the legal entity name and address in the site footer, terms of service or invoices.
2. Look the entity up in the business register for the country or state it names. Examples are Companies House in the UK [7] and ABN Lookup in Australia [8]. In the US, each state’s business registry is usually run by the Secretary of State.
3. Check that the registered name and address match what the site shows.

Red flags: no legal name anywhere; an address that is a mailbox service presented as a “lab”; a company registered in one place while the site claims another.

Check 5: Shipping, refund and terms pages

Why it matters. Policies tell you what happens when an order is lost, seized at the border, damaged or wrong. Their absence tells you something too.

How to check. Read three pages: shipping, refunds and returns, and terms. Look for who pays when a parcel is lost or held, whether there is a reship or refund policy, and how to contact support. Many vendors’ terms also include “research use only” language. Read our explainer on what that label means.

Check 6: Payment you can dispute

Why it matters. A payment method with dispute rights is your only real recourse if nothing arrives.

How to check. Go to checkout without paying and see which payment options are offered.

• Credit card. US federal law lets you dispute a billing error, including goods not delivered as agreed. Your letter must reach the issuer within 60 days after the first bill with the error was sent [5].
• Bank transfer, wire, crypto, payment apps or gift cards. The FTC warns that anyone who says you can only pay in one of these ways is probably a scammer. It advises paying by credit card whenever possible [4].

Scam patterns we see repeatedly

• Crypto-only or app-only checkout. This is the payment pattern the FTC flags as a scam signal [4].
• Look-alike domains and cloned stores. A one-letter change, a different ending (.co instead of .com) or a copied design. Type the vendor’s domain yourself instead of clicking ads or links in messages.
• Fake “successors” to closed vendors. When a known vendor shuts down, impostors follow. Science.bio’s own closure notice warns that any site claiming to be Science.bio or its successor is fraudulent [3]. Run Check 1 on any “new home” of an old brand. We list the cases we’ve documented in look-alike peptide vendor sites.
• Sudden closing sales. A real closure can come with discounts and instructions for pending orders, but a “final sale” is also an easy cover for taking payments that will never ship. If you buy, use a card.
• Review walls. Reviews on a vendor’s own site are easy to filter or fake. The FTC’s rule against fake reviews and testimonials, announced in August 2024, covers fake and AI-generated reviews and company-controlled “independent” review sites [6]. Compare on-site reviews with independent sources.
• Prices far below the market. Compare a vendor’s $/mg with the market on our price index. An outlier can mean a mislabeled or under-filled product, or a store that never ships. The FDA lists “deep discounts or prices that seem too good to be true” among the warning signs of an unsafe online pharmacy [9].

Putting it together

A vendor that passes all six checks has shown you a lot. It still hasn’t shown you what is in the vial. A vendor that fails several checks is asking for trust it hasn’t earned. We run these checks on every vendor we list and record the evidence: the best peptide vendors list ranks the vendors we could complete all six checks for, by how they score, and every vendor in the vendor list has a profile with its results. If a vendor thinks we’ve got something wrong, our corrections page explains how to send proof.