How to Read a Peptide HPLC Analysis Report

A peptide HPLC report states purity as the percentage of the main peak area over the total detected area. That number — area% — is the central figure. Everything else in the report exists to show that the number was produced by an identifiable laboratory, using a reproducible method, on a sample traceable to a specific lot.

PeptoClinic publishes four certificates of analysis in the quality section, each carrying the Janoshik Analytical task number.

The chromatogram: two axes and a main peak

A chromatogram is a plot of time against signal. The horizontal axis shows time in minutes — how long each compound took to travel through the chromatographic column. The vertical axis shows UV light absorption, expressed in milli-absorbance units (mAU).

When a compound exits the column and passes in front of the UV detector, it produces a peak. The peptide of interest produces the largest peak. Every additional peak represents a different compound: a synthesis by-product, a degradation fragment, or an impurity.

A high-purity peptide has one dominant peak and a nearly flat baseline outside of it. If several peaks of comparable height appear, the sample contains more than one relevant compound.

Why 220 nm

Peptide analysis is typically run at 220 nm because the peptide bond absorbs light at that wavelength. That makes the method sensitive to any peptide regardless of amino acid sequence. Some protocols add 280 nm for peptides with aromatic residues — phenylalanine, tyrosine, tryptophan — but 220 nm is the standard for reporting chromatographic purity.

How area% is calculated

The HPLC software integrates the area under each peak. Purity is the main peak area divided by the sum of all peak areas, multiplied by one hundred.

If a report states 99.7%, the remaining 0.3% is the combined area of every secondary peak the detector recorded. A trustworthy report shows the complete peak table — each peak with its retention time and its area% — and the figures sum to 100%.

A number without the table behind it is not verifiable.

What a valid report must include

A certificate of analysis from an independent laboratory includes these elements:

• Laboratory name and task number. The task number is the unique identifier for that run. Without it, there is no way to trace the analysis.
• Date of analysis. Not the date the PDF was printed — the date the sample was actually run.
• Compound name and lot number. This connects the report to the physical material.
• Method details. Column, mobile phases, wavelength, gradient. Without this, the method is not reproducible.
• The chromatogram. The image of the elution profile. A PDF that shows only a number, without the chromatogram, is not a certificate of analysis.
• Peak table. Retention time, area, and area% for every detected peak.

A report that meets those criteria can be evaluated. One that omits the chromatogram or the peak table does not contain enough information to confirm the number it claims.

The Janoshik Analytical certificates

The four certificates published by PeptoClinic correspond to analyses performed by Janoshik Analytical on April 13, 2026.

For Retatrutide, task 136921 recorded a purity of 99.893%. The vial carried a 10 mg label; the analysis found 11.96 mg of total content.

For MOTS-c, task 136923 recorded 99.669%. The measured content was 11.31 mg.

GHK-Cu (task 204977) and BPC-157 with TB-500 (task 204975) each have their certificates with the task number included. The lowest purity PeptoClinic has published is 99.669%. That figure — not the best lot, but the worst published — is the one that sets the floor.

Two of the four certificates carry a working verification link on the Janoshik site. The other two carry a task number but the laboratory's online verifier is intermittently unavailable. For those reports, the verification path is to contact Janoshik directly with the task number.

Red flags in a questionable report

There are real differences between a genuine report and a fabricated PDF.

No task number, or a task number that does not exist in the laboratory's system. If the task number cannot be found in the declared laboratory's database, the report was not generated by that laboratory.

A chromatogram without scale. A chromatogram that lacks numbered tick marks on the time axis or values on the absorbance axis is a decorative image, not analytical data.

The peak table does not sum to 100%. Area% always totals 100. If the table omits peaks or uses rounding that does not close, information is being withheld.

The main peak has an unusually short retention time. Mid-length peptides elute within expected ranges for a given method. A main peak appearing at very short retention times may correspond to water, residual solvent, or a compound different from the one declared.

A supplier that cannot provide the task number of the laboratory that supposedly analyzed the lot has no way to demonstrate that the analysis took place. Requesting it before any decision is reasonable.

Laboratory research material

The peptides PeptoClinic supplies are research material exclusively — Research Use Only (RUO). They are intended for in vitro and laboratory research. They are not medicines, not supplements, and no regulatory authority — not the FDA, not ANMAT, not any equivalent body — has evaluated or approved them for use in people or in animals.

PeptoClinic is not a pharmacy, not a clinic, and does not provide administration protocols. The HPLC analysis accompanying each lot documents the purity of the material as a research compound. Quotations include the technical documentation for the lot. For availability inquiries, write to [email protected] or review the compound catalog.