Think of a Certificate of Analysis (COA) as a laboratory report card for a peptide. It helps answer three simple questions: What was found? How pure was it? And how much was measured?
You don’t need a chemistry background to get started. We’ll show you where to find the important numbers, what they actually tell you and how to check a report for yourself, using two genuine VialTests laboratory reports for a four-component KLOW research blend.
1. Start with the sample and report numbers
Before looking at purity percentages, make sure you know which sample was analyzed. The three identifiers below help you match a vial, a laboratory sample and its two test reports.
Lot numbers, sample IDs and report numbers — what’s the difference?
A COA has several strings of letters and numbers. They may look interchangeable, but each one answers a different question. Here’s how to trace the actual KLOW sample from the vial label to its laboratory results.
Lot number: where it came from
E8-2603-01L
Usually assigned by the producer to identify a group of material. It helps link the tested sample to a labelled lot. A lot number by itself doesn’t mean every vial was individually tested.
Sample ID: what the lab received
VT-001741-S01
VialTests’ identifier for the submitted sample. Notice this same sample ID appears on both the composition report and the heavy-metals report.
Report number: which test to verify
VT-2026-001741
This identifies the composition report. The companion heavy-metals result has its own number, VT-2026-001741-02. Different report numbers can relate to the same sample.
2. How peptide identity is tested
KLOW contains four named peptides: GHK-Cu, BPC-157, TB-500 and KPV. For this submitted sample, VialTests reports HPLC-MS/MS using an Agilent 1290 Infinity II and Agilent 6495 QQQ. This combines chemical separation with mass-spectrometric evidence about the compounds detected.
How HPLC-MS/MS works in practice
HPLC separates the mixture; MS/MS helps identify its components. Here’s how they work together.
A sample is prepared for analysis. This public COA doesn’t describe the lab’s exact preparation steps.
Liquid carries compounds through a specialized column. They travel through it differently, emerging at different times.
Ions are measured by mass-to-charge ratio, then selected ions are fragmented to reveal identifying chemical patterns.
The report gives a separate measured amount and chromatographic purity result for each peptide in the blend.
What is HPLC? Think of a chemical race.
HPLC stands for high-performance liquid chromatography. Imagine a group of runners entering a course together but reaching the finish line at different times. In HPLC, those “runners” are compounds moving through a column, while a liquid called the mobile phase carries them along.
Different molecules interact differently with the column’s material, so they separate. Their arrival times help distinguish them. HPLC is useful for seeing whether there is one dominant component or a mixture of detectable components — and for helping determine chromatographic purity.
What’s a chromatogram, and what do the peaks mean?
A chromatogram is a graph of detector signal against time. A peak represents a signal from material reaching the detector at a particular time, called the retention time. A larger peak may represent more signal, but peak height alone isn’t the same as purity or quantity.
Laboratories can calculate chromatographic purity using the relative signals from relevant peaks, depending on the method. Importantly, the VialTests KLOW certificate provides the reported percentages, but it doesn’t display the raw chromatograms, so we shouldn’t invent or reconstruct individual peaks from this report.
What does MS/MS add that HPLC alone can’t tell you?
MS means mass spectrometry. It measures ions according to their mass-to-charge ratio (m/z). MS/MS, or tandem mass spectrometry, goes a step further: the instrument selects ions and studies the fragments they produce. This helps distinguish compounds whose chromatographic signals or molecular masses might otherwise look similar.
That is why combining separation with mass-spectrometric evidence can be particularly useful for a blend such as KLOW. The test is chemical identity evidence; it is not itself a biological-effect experiment.
Follow the numbers on an actual COA
Start with this annotated walkthrough. The centre is the original VialTests composition report; the numbered explanations show which sections to look at first. Tap to enlarge it.
View the original composition report (tap to expand)
3. What does 99%+ purity actually mean?
Chromatographic purity estimates the proportion of signal attributable to the target component within the test method’s chromatographic measurement. A high value suggests relatively little detectable peptide-related impurity in that measurement. It is not the same thing as saying that 99% of the entire vial’s physical mass is pure peptide.
Here are the values VialTests reported for the submitted KLOW sample:
| Peptide | Label claim | Measured net content | Chrom. purity |
|---|---|---|---|
| GHK-Cu | 50.00 mg | 55.66 mg | 99.83% |
| BPC-157 | 10.00 mg | 12.29 mg | 99.62% |
| TB-500 | 10.00 mg | 11.96 mg | 99.60% |
| KPV | 10.00 mg | 11.79 mg | 99.58% |
| Total | 80.00 mg | 91.70 mg | Reported separately by component |
GHK-Cu
BPC-157
TB-500
KPV
Total measured
What stands out: All four peptides have separate chromatographic purity results above 99.5%. That component-by-component detail is especially useful for evaluating a blend.
4. Purity versus net peptide content: two different numbers
One of the most common mistakes is to confuse purity with amount. The COA lists both. For example, GHK-Cu has a reported chromatographic purity of 99.83%, but its separately measured net content is 55.66 mg against a 50 mg label claim. Those figures answer different questions.
The blend’s total net peptide content was 91.70 mg compared with the declared 80.00 mg, which the lab expresses as 114.6% fill accuracy. In plain language, the measured amount was 14.6% above the label claim, rather than an underfill. An amount above the label is not the same as an exact match, so suitability for a research protocol still depends on the protocol’s required concentration and tolerance.
The separate 135.2 mg total sample mass is not the net peptide content. A composition COA does not by itself characterize the non-peptide share of that mass, and the difference should not be interpreted as a measured list of excipients.
How does a lab measure the actual milligrams?
Quantitative assays generally compare the instrument’s response with reference standards or calibration data to estimate the amount of a peptide. The KLOW COA reports net content for each component, but does not include the underlying calibration curves. Those measured quantities are distinct from the chromatographic purity percentages.
5. Reading the heavy-metals report
The companion COA measures a different property: trace levels of lead, cadmium, arsenic and mercury, rather than peptide composition. Here’s how that laboratory test works.
How ICP-MS detects heavy metals
ICP-MS stands for inductively coupled plasma mass spectrometry. The steps below show how the instrument detects minute concentrations of elements.
The lab prepares material for elemental testing. This report doesn’t list the exact preparation protocol.
A very hot plasma converts elements in the introduced sample into ions.
The mass spectrometer separates and detects ions, allowing very small amounts to be measured.
Results are reported by element, with a measured concentration or a below-detection designation.
Read the units: The COA reports concentrations in µg/g (ppm) and includes its laboratory reference bars. ICH Q3D exposure limits are also expressed in µg/day, so interpreting those limits depends on the amount of material involved.
Heavy-metals COA: visual walkthrough
The companion infographic explains how to read the four metal results and the term BDL. It’s a visual learning aid; the original laboratory report directly below remains the definitive source for the exact test findings.
View the original heavy-metals report (tap to expand)
| Metal | Reported result | How to read it |
|---|---|---|
| Lead (Pb) | BDL | Below the method’s detection limit |
| Cadmium (Cd) | 0.005 µg/g (ppm) | Low measured concentration |
| Arsenic (As) | 0.018 µg/g (ppm) | Low measured concentration |
| Mercury (Hg) | BDL | Below the method’s detection limit |
What stands out: These are encouraging results for the four metals screened in the submitted sample. The infographic above explains the figures; the table gives the exact reported values.
6. Verify the COA with the laboratory
A report screenshot is helpful, but a verifiable record is stronger. Open the VialTests links below and compare the report number, sample ID and issue date with your copy. Each KLOW test has its own report number, even though both refer to the same submitted sample.
What the results tell us
The KLOW laboratory reports provide detailed, independent measurements: all four peptides identified and quantified, chromatographic purities of 99.58–99.83%, and a separate heavy-metals screening panel. Together, the results give researchers meaningful evidence about the identity, composition and tested contaminants of the submitted sample.
The independent testing featured in this guide was performed by VialTests. You can check the original reports using the verification links above.
Explore the KLOW research blend and lab results at Elev8 Lab → (affiliated site)
Laboratory attribution: The COA images and underlying analytical results are credited to VialTests and reproduced for educational discussion with permission. Original reports: VT-2026-001741 and VT-2026-001741-02, issued October 7, 2026. The reports are reproduced without changing their results.
Scope: Results describe only the samples analyzed. They do not establish results for every vial or entire lot, nor do chemical composition and contaminant tests measure sterility, biological activity, clinical efficacy or authorization for human or veterinary use. Research use only.