Lab reports: how to read the paperwork for a batch
· Novatheris
A lab report is not a stamp of approval with one number on it. It is several separate measurements, and each one answers a different question.
Once you know which question each section answers, the report stops being a nice-looking piece of paper and becomes something you can check yourself. Here it is, part by part.
The five questions a report answers
A full analysis can measure five different things:
- Quantity: how many milligrams of peptide are in the vial.
- Purity: how clean that peptide is compared to other similar compounds.
- Identity: whether it really is the compound the label says it is.
- Endotoxins: how much bacterial residue it carries.
- Heavy metals: whether toxic metals show up.
None of the five covers the others. A high purity number says nothing about endotoxins, and a metals report says nothing about how many milligrams are in the vial.
Purity: the main peak against everything else
Peptide purity is measured by HPLC, a technique that separates the components of a sample and detects them one at a time with ultraviolet light, between 210 and 220 nanometers.
The result is a graph made of peaks. Purity is the area of the main peak divided by the total area of all the peaks. If the main peak takes 99.7 % of the area, that is the number that goes on the report.
Watch this part closely: it is a percentage relative to what the detector can see at 220 nm. It does not mean "99.7 % of the powder in the vial is peptide." The salt and the water that come with the powder do not absorb at that wavelength, so they never enter the math.
Identity: confirming it is what it claims to be
A clean peak does not tell you which compound it is. Something can be extremely pure and still be the wrong thing.
That is what mass spectrometry is for. It measures the molecular weight of the sample and compares it to the weight the compound should have. On our Freedom Diagnostics Testing certificate NOVA2609150054, for Retatrutide 20 mg (batch NVT-2609-16), the stated method is "HPLC with UV detection coupled with mass spectrometry (LC-MS)".
That report prints both graphs: the chromatogram, with a single peak near the 15-minute mark, and the mass confirmation.
Net content: how many milligrams are really there
This is the measurement that confuses people most. Peptides are supplied as salts, with acetate or trifluoroacetate, and with some water stuck to them. That material has weight, but it is not peptide.
Net content is the fraction that actually is peptide, and it is calculated by measuring nitrogen, because salts and water contain no nitrogen.
That is why a report can say "Purity 99.99 %" and "Net Content 23.28 mg" on a vial labeled 20 mg. There is no contradiction: the label is nominal and the analysis measures what is there. Same story on Janoshik report #123821, for Tirzepatide 30 mg (batch NVT-TZ30-0626-01), which reports 35.48 mg and a purity of 99.678 %.
Endotoxins: a test of its own
Endotoxins are residues from gram-negative bacteria. They are measured with the LAL test (Limulus Amoebocyte Lysate), which the FDA has accepted since 1977 in place of the old rabbit pyrogen test, and the reference chapter is USP 85.
The result is given in EU, endotoxin units. Our Janoshik report #123822, from that same Tirzepatide batch, reports "Endotoxin under 1 EU/Vial".
Two things worth keeping apart: endotoxins and sterility are not the same test. The first measures bacterial residue, the second measures whether live microorganisms are present. An endotoxin report says nothing about sterility.
Heavy metals: the usual four
The international reference for metal impurities is the ICH Q3D(R2) guideline. The Class 1 metals, the most toxic ones and the ones that always have to be evaluated, are cadmium, lead, arsenic and mercury.
That guideline sets what counts as acceptable by the parenteral route: 2 micrograms a day of cadmium, 5 of lead, 15 of arsenic and 3 of mercury.
Janoshik report #123823, from the same batch, reports arsenic, cadmium and lead as "not detected", and in the comments "Hg: not detected". Exactly those four.
What "not detected" means
It does not mean zero. It means below what the method can see.
Every instrument has a floor. Below a certain amount, it can no longer tell signal from noise. "Not detected" means that if something is there, it sits under that floor. Good news, yes, but not the same thing as absolute absence.
Every batch carries its own report
This is the part people skip most. A report describes one batch, the one that was tested, and nothing else.
That is why every report has its batch code printed on it along with its own verification key. The Janoshik ones carry the line "Verify this test at www.janoshik.com/verify/" with a unique key. For the Tirzepatide, it is 67KIHU39DAB2 for purity, ZF2DPKKKR4B2 for endotoxin and AYP4BL9XKY7H for metals.
Freedom reports are looked up on their page by "search code", four client letters plus the accession number. If a report does not match your batch, it tells you nothing about your vial.
What each report looks like inside
The two formats are different, and that helps.
Janoshik issues a Test Report per test: purity, endotoxin and metals are three separate documents. Each one carries a task number, client, sample, manufacturer, batch, test requested, results table, comments, analysis date, signature and the verification key.
Freedom issues a longer Certificate of Analysis, with a photo of the vials, a sample summary, analytical results, method, chromatogram, mass confirmation and the signature of the principal chemist. The footer states that the peptides tested are for research use only and are not approved for human or veterinary use.
Four mistakes that keep coming back
- "99.7 % purity means 99.7 % of the powder is peptide." No. Purity is relative to what the detector sees, and the weight includes salt and water.
- "High purity means it is sterile." No. Purity, endotoxins and sterility are three different tests.
- "Not detected equals zero." No. It is below the limit of the method.
- "35.48 mg in a 30 mg vial is a mistake." No. The label is nominal and the analysis measures what is there.
If you want to see all of this in a real document, every vial carries its batch code and you can look up its report in the verification section.