Where to find a GLOW peptide COA

Look for the COA on the supplier’s product page or in the batch documentation. If you’re given a summary image, check whether it includes a QR code or link to the supporting report. Before reading the results, make sure the product description and lot number match the material you’re researching.

The checklist below follows WHO laboratory-reporting guidance. It shows which fields to check, rather than reproducing a supplier’s certificate for a particular batch.

An identity result and a purity result answer different questions. Read the method and acceptance criterion beside each one. Neither result, by itself, supplies a measured amount for every ingredient in a blend.

Match the COA to the sample

Match the product description and lot number on the material to the document. The laboratory’s sample number and report number may differ from the production lot number; the records should connect them. WHO’s reporting guidance distinguishes all three identifiers. WHO report fields.

Next, identify what was tested: an individual ingredient, a bulk blend or a finished vial. A result for a GHK-Cu ingredient alone does not describe the other two ingredients in a finished blend.

Read the test date and retest date separately. One records when testing occurred; the other identifies when reassessment is due. The dated result also needs to be read alongside the material’s storage conditions.

Identity: which peptides were identified?

MS means mass spectrometry. It provides molecular-mass information that helps identify a peptide. Tandem mass spectrometry, written MS/MS, breaks molecules into fragments to obtain additional sequence information. USP researchers used these measurements alongside other techniques to characterize peptide reference standards. McCarthy and colleagues’ original analytical study.

For GLOW, read the identity findings for GHK-Cu, BPC-157 and the specific molecule described as TB-500. An identity pass means the stated identification criterion was met; it is not a measurement of the number of milligrams present.

Keep the full molecular description when comparing a report with research. In one analytical study, a preparation called TB-500 contained an acetylated, seven-amino-acid thymosin fragment. That finding applies to the preparation tested, not every product bearing the name. Esposito and colleagues’ TB-500 analysis. The GLOW stack guide explains these ingredient distinctions.

HPLC purity: what does the percentage measure?

HPLC means high-performance liquid chromatography. It separates sample components for detection. On a chromatogram, a peak represents a detected signal. When purity is reported as an area percentage, selected peak areas are compared with the total area included by that method. ICH analytical-method guidance.

For a blend, establish which peaks are assigned to the intended ingredients and whether the percentage describes one ingredient or a combined result. BPC-157 and TB-500 are intended components of GLOW; their presence alongside GHK-Cu does not make them impurities.

Peak areas are not automatically mass fractions. Compounds can produce different detector responses, so the method may need response corrections. A 5:1:1 ratio by mass need not produce a 5:1:1 pattern of raw peak areas. ICH guidance on relative response factors.

A hypothetical purity calculation

Suppose a method assigns 990 area units to the intended components and 10 area units to other included peaks:

990 ÷ (990 + 10) × 100 = 99.0% area.

These invented values explain the arithmetic. They do not describe a real batch or reconstruct a certificate. The calculation tells you the share of included detector response, not the total peptide mass or any ingredient’s milligrams.

Quantity: how much of each ingredient was measured?

Look for a quantitative assay in mg per vial, or another unit that answers the amount question. A laboratory can use a characterized reference material to calibrate an HPLC assay for peptide mass. Calibration connects the measured response to a known amount. Peptide mass-content assignment in McCarthy et al..

The combined total and the amount of each ingredient answer different questions. This invented 30 mg example shows why; none of these label or assay values describes a real product or batch.

Scroll to compare all columns →

The total matches, while the individual amounts differ. Each percentage is measured amount ÷ labeled amount × 100. Whether a result passes depends on the applicable acceptance criteria; this example does not set a pass range.

Why content and purity percentages can differ

A content percentage needs a stated basis, such as material as received or material corrected for water. Peptide impurities, water, associated ions such as acetate, and residual solvents contribute separately to mass-balance testing. They are not all measured by one chromatographic area percentage. Laboratories can measure water by Karl Fischer titration and residual solvents by gas chromatography. McCarthy et al., mass-balance characterization.

Read what each percentage is a fraction of before comparing or subtracting it. Check whether the laboratory has already applied a water or other correction.

“Below detection” means the test did not detect the substance above its detection limit. “Below quantitation” means the amount was below the method’s reliable quantitative range. Neither is a measurement of exactly zero. ICH definitions of detection and quantitation limits.

Does high purity mean sterile or endotoxin-free?

No. Chemical purity, sterility and bacterial endotoxins require different measurements.

Sterility testing looks for viable microorganisms that can grow under the test conditions. Its result applies to the sampled material and the method used. FDA’s explanation of sterility-test scope.

Bacterial endotoxin testing uses its own assay, units and acceptance limit. Read the numerical result against that limit, including any “less than” qualifier. The method also needs to account for interference from the material being tested. An HPLC purity percentage cannot substitute for this result. FDA’s endotoxin-testing guidance.

These tests characterize a sample. Clinical benefits and a safe human regimen require different evidence, examined in the GLOW peptide research guide.

Certificate of Analysis versus Certificate of Authenticity

A Certificate of Analysis records laboratory findings. To verify one, use its report number or verification route to match the issuing record, sample identifiers and results. Keep the complete report with the corresponding lot information.

A Certificate of Authenticity can verify an order. A supplier may use an authenticity card or verification code to check an order in its own records. That confirms a different kind of record from an analytical test result.

The GLOW buying guide covers the listing, purchase details and order documentation.

Citation audit: October 16, 2026. The reporting checklist follows public laboratory guidance. The numerical teaching examples elsewhere in this article are invented and are identified as such.