Peptide Guides
Important
The peptides described on this site are not approved medicines. They hold no licence from the MHRA in the United Kingdom, the EMA in Europe, or the FDA in the United States. This guide explains laboratory testing documents. It is not medical advice, and nothing within it constitutes a recommendation to use any compound. Products supplied through this site are intended for laboratory research use only.
Quick answer
- A certificate of analysis (CoA) is a document from a testing laboratory stating what a specific batch of product contains.
- For peptides it should show two results. Purity is measured by a test called HPLC, and identity is confirmed by a test called mass spectrometry.
- The batch number on the certificate should match the number on the vial, and the certificate should be dated.
- A CoA proves what is in the vial. It does not prove a product is sterile, safe, or effective.
What is a certificate of analysis?
A certificate of analysis, usually shortened to CoA, is a document produced by a testing laboratory. It states what a specific batch of a product was found to contain when a sample of it was tested.
Peptides are made in production runs, and each run is a batch with its own number. A certificate belongs to one batch, not to a product in general. A certificate for last year's batch says nothing about a vial produced this month.
Research peptides sit outside the medicines system, so no regulator tests them. Our guide to what research use only means covers that framework. The certificate of analysis is the only independent evidence of what a vial actually contains.
HPLC purity explained
The main number on a peptide CoA is purity, and it comes from a test called high-performance liquid chromatography, or HPLC.
The test works by separation. The sample is dissolved and pushed through a narrow tube packed with fine material. Different substances travel through the tube at different speeds, so a mixture comes out the other end separated into its parts, and a detector measures how much of each part there is.
The purity figure is the share of the sample that is one single substance. A result of 99% purity means 99% of what was measured is one compound, and 1% is something else, usually leftover fragments from the manufacturing process.
The purity test does not say what the main substance is. That needs a second test.
Mass spectrometry identity explained
Mass spectrometry is a test that weighs molecules. Every peptide has a known molecular weight, set by which amino acids it is made of. Amino acids are the small chemical units that peptides and proteins are built from, and each kind has its own weight.
If the measured weight of the substance in the vial matches the known weight of the named peptide, the identity is confirmed. If it does not match, the vial contains something else, whatever the purity figure says.
Purity and identity together are the complete answer. Purity says how much of the sample is one substance. Identity says the substance is the peptide on the label. A certificate showing only purity has answered half the question.
How to read a peptide CoA step by step
A certificate can be checked in under a minute against four fields.
1. The batch number. It should match the batch number printed on the vial received. A certificate with no batch number, or one that does not match, is not evidence about that vial.
2. The purity result. The HPLC figure, stated as a percentage. Research-grade peptides commonly test at 98% or higher.
3. The identity result. A mass spectrometry confirmation that the measured weight matches the named peptide.
4. The date. Testing should be recent enough to relate to the stock on sale. A certificate dated long before the batch went on sale suggests testing is not routine.
The name of the laboratory that performed the testing should also appear.
Third-party testing versus in-house testing
Testing can be done by the seller's own laboratory or by an independent one. The difference is who has an interest in the result.
An in-house result is better than no testing. An independent laboratory's result counts for more, because an outside laboratory earns nothing from a good number and loses its accreditation for false ones. Where a seller names the independent laboratory on the certificate, the claim can also be checked with that laboratory directly.
We use an independent third-party laboratory to confirm what our vials contain. Every batch we sell is sampled and sent out for testing before it is listed. The outside laboratory measures purity by HPLC and confirms identity by mass spectrometry, and we publish its dated certificate of analysis for download. The batch number on the certificate matches the vials from that batch, and archived certificates stay available after a batch sells through.
What a CoA does not prove
A certificate of analysis answers a single question, which is what the vial contains. Three related questions sit outside it.
It does not prove sterility. Purity is a chemical measure, not a measure of germs. Sterility is a separate manufacturing standard that research-grade products are not certified to meet.
It does not prove safety. What a compound does in a body is a question for controlled studies, not for a chemistry test. A vial can be exactly what its label says and still be a compound no human trial has ever assessed.
It does not prove effectiveness. Our full guide to BPC-157 shows what that distinction looks like for the most searched peptide, with verified contents and unverified effects.
A certificate establishes what the vial contains. Sterility, safety and effectiveness each need separate evidence.
CoA red flags
No certificate at all, or certificates available only on request. A supplier that tests every batch can publish a certificate for every batch.
No batch number, or a number that does not match the vial.
Purity with no identity test. Purity alone does not confirm the substance is the peptide named on the label.
A stale date. Testing from long before the current stock suggests one certificate is serving many batches.
No named laboratory. A certificate that cannot be traced to the laboratory that produced it cannot be checked.
A recycled document. The same certificate appearing for different products or batches is not evidence about any of them.
Common questions about certificates of analysis
What is a certificate of analysis for peptides?
A document from a testing laboratory stating what a specific batch was found to contain. It reports the purity of the material and confirms it is the peptide named on the label. It is the only independent evidence of a research peptide's contents, because no regulator tests them.
What does 99% purity mean?
It means 99% of the tested sample is a single substance and 1% is something else, usually manufacturing leftovers. It does not by itself confirm what the substance is. The identity test does that. Purity also says nothing about how the material was handled after testing, which our guide to reconstituting peptides covers.
Can certificates of analysis be faked?
Yes. A CoA is a document, and documents can be copied, edited or reused. Three checks make faking harder. They are a batch number that matches the vial, a named independent laboratory the result can be verified with, and a recent date. A certificate failing those checks deserves no weight.
Does a CoA mean a product is safe?
No. A certificate proves contents, not effects. A vial can contain exactly what its label claims and still be a compound that has never been assessed for safety in humans, which is the position for most research peptides.
Specification and supply
Peptides supplied through this site are freeze-dried (lyophilised) powder, purity-tested by HPLC with identity confirmed by mass spectrometry, with a dated certificate of analysis published per batch. The full range is listed under research peptides.
Supplied for laboratory research use only. Not for human consumption.