Lot-Matched CoAs Published
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How to read a peptide Certificate of Analysis

A walk through our real Retatrutide 10mg certificate, section by section.

Open the full certificateAll lab reports

Section by section

  1. Page 1

    Who tested it

    An independent analytical lab, not us. Its name, address and email head both pages.

    Testing laboratory letterhead with address and email, from the Retatrutide 10mg certificate
  2. Page 1

    The batch

    Lot number is the batch that was tested. Analysis date is the day the lab ran it.

    Certificate fields: compound Retatrutide, lot number 2026-07-15, analysis date 2026-07-31
  3. Page 1

    The result

    99.99% pure. HPLC-UV-MS means purity by HPLC, identity by mass spec.

    Certificate fields: purity 99.99%, method HPLC-UV-MS
  4. Page 1

    The chromatogram

    The tall spike at 7.01 min is retatrutide. Impurities show up as extra peaks. There is just one here, a tiny one at 7.28 min.

    HPLC chromatogram for Retatrutide 10mg: one main peak at 7.01 minutes and a tiny peak at 7.28 minutes
  5. Page 1

    The peak list

    The chart as numbers. Retatrutide is 99.99% of the total area, the tiny peak 0.01%. That is where the purity figure comes from.

    Peak list: peak 1 at 7.01 minutes, 99.99% of area, retatrutide; peak 2 at 7.28 minutes, 0.01%
  6. Page 2

    The identity check

    Mass spec weighs the molecule. Expected 4,728.47 Da, measured 4,728.54 Da. That match confirms it is retatrutide.

    Mass spectrometry identity test: expected monoisotopic mass 4728.47 Da, measured 4728.54 Da, molecular weight confirmed
  7. Page 1

    Signed off

    Signed by the lab's analytical chemist, and dated the day the report was issued.

    Analyst sign-off: analytical chemist's name, signature and report date 2026-08-06

Good to know

  • Every UK Peptides certificate uses this same two-page layout.
  • Salts and buffers don't show up under UV, so they aren't counted as impurities. The lab notes this at the foot of page 1.
  • It tests purity and identity. It doesn't weigh how much powder is in the vial.

Check it yourself

  1. 1.Open the certificate on the product page, or in Lab Reports.
  2. 2.Check the compound and size at the top match what you're buying.
  3. 3.Click the PubChem link on the certificate. It should open the compound named at the top.

Peptide CoA questions

What is a peptide Certificate of Analysis?
A lab report on one batch of a peptide. Ours shows the purity (HPLC), the identity (mass spectrometry), the batch, the dates and the chemist who signed it.
What does 99.99% purity mean on a CoA?
Of everything the UV detector picked up, 99.99% was the named peptide. The figure comes from the peak list on page 1 of the certificate.
What does the mass spectrometry result prove?
That it is the right molecule. The lab weighs it and compares the result with its known mass. For retatrutide: 4,728.47 Da expected, 4,728.54 Da measured.
Who tests UK Peptides products?
An independent analytical lab, not us. Its name, address and the chemist who signed the report are printed on every certificate.
Does the certificate show how much powder is in the vial?
No. It tests purity and identity. It does not weigh the fill of the vial, and we would rather say so than let the word tested imply it.
Where do I find the certificate for my product?
On every product page except those of new products still waiting on their lab report (currently Tesamorelin and PT-141), and all of them are together in Lab Reports.

Further reading