How we test
You cannot tell anything about a peptide by looking at it. Every meaningful difference between one supplier and another is in the documentation — which is exactly why so little of it is published.
Synthesis
Peptides are built one amino acid at a time on a solid resin support, then cleaved and purified. Nothing is grown or extracted. The sequence is determined at this stage; everything after it is about proving what actually came out.
Purification
The crude product is separated from truncated sequences, deletion products and residual reagents. This is where the number on a certificate is really decided — two vials of the same compound from different runs are not necessarily the same material.
Independent testing
Batches are tested by Freedom Diagnostics, an independent third-party laboratory. Not by us, and not on the strength of the manufacturer’s own paperwork alone. The lab has no commercial interest in the result.
Batch-matched certificate
The certificate reports identity and purity by HPLC, the method used and the test date — and it is tied to the specific lot number printed on the vial you receive.
Published, searchable by lot
Certificates go into a public library you can search by lot number before or after ordering. You do not have to ask us for one, and you do not have to take our word for what it says.
How to check any supplier, including us
Four questions. They take a minute, they cost nothing, and a supplier who cannot answer them has told you something useful.
- Does the certificate carry a lot number, and does it match the vial?
- Who ran the test, and are they independent of the seller?
- What method was used, and what was the test date?
- Can you see the certificate before ordering, without asking for it?
Questions we get asked
Why does "batch-matched" matter so much?
Because a certificate that cannot be tied to a physical lot proves nothing about the material in front of you. A generic PDF reused across production runs is the industry norm and it is close to meaningless — it describes a batch somebody once tested, not the one you are holding.
Why don’t you advertise a purity percentage?
Because purity varies between production runs, so a single site-wide number would be an average at best and a marketing claim at worst. We publish the measured figure for each batch instead, and you can read it before you order.
Is Freedom Diagnostics accredited?
They are an independent third-party laboratory with no commercial interest in the outcome of a test. We do not make an accreditation claim on their behalf — if a supplier tells you a lab is ISO 17025 or UKAS accredited, ask them to name the accreditation body and the scope, because those are verifiable and vague versions of the claim usually are not.
What is actually on the certificate?
Identity and purity determined by HPLC, the analytical method used, the test date, and the lot number it corresponds to. That last field is the one worth checking against your vial.
Can I see a certificate before I order?
Yes. The library is public and searchable without an account. That is deliberate — the documentation is the product as much as the powder is.
All materials are supplied for in-vitro laboratory research use only. Not for human or veterinary consumption. PepcoLab is the trading name of SEE BEE DEE LIMITED, registered in England and Wales, company number 17072052.