The NexPept report library
Certificates of analysis.Find your batch.
Search third-party laboratory reports for NexPept research peptides. Match the product, the labelled strength and the lot number on your vial, then open the original certificate.
An expanded testing panel
Endotoxin and heavy metals.
Alongside HPLC purity and mass spectrometry identity confirmation, every new batch now carries endotoxin and heavy metal testing. A number of lots already published here include both.
Panels vary by lot and by compound. Each batch's own certificate is the record of what it was tested for — open the report for the completed panel. Research use only.
How to read your certificate.
Every certificate in this library is the laboratory's own report. Seven things on it tell you what you need to know. Hover the document to look closer, or pick a step.
Search the library
Your report, a few details away.
Current and historical reports, together.
Combine details such as “Retatrutide 10mg”, or search the batch number printed on your vial.
Every certificate is the issuing laboratory’s own report, published as received. Lots stay listed after they sell out so earlier reports remain available. Research use only.
Reading the evidence
What a certificate can tell you.
A certificate of analysis records what the laboratory measured in the sample it was given. Start by matching the sample to your vial, then read each result next to the method and the limit it was measured against.
1.Match the sample
Check the compound, the labelled strength and the lot number against your vial. A matching product name on its own does not establish a batch match.
2.Read the measurements
Purity, measured content and contaminant screens are separate results. Look at the units, the limit each is compared against, and any footnotes on the page.
3.Confirm the source
Check the run date and the generated date, then take the report number to the issuing laboratory and confirm the result at the source rather than with us.
| Report field | What to look for |
|---|---|
| Lot number | Printed top right of the report, beside the client name. It has to match the lot on your vial — this is the only field that ties the report to the vial in your hand. |
| Report number | The laboratory’s own reference for the run. It is not the same as the lot number, and it is what you quote when verifying the report with the lab. |
| Identity | Whether the peak measured is the named compound, confirmed against a reference standard. Purity without identity tells you the vial is clean, not what it is clean of. |
| HPLC purity | The main peak as a share of all integrated peak area, at the stated wavelength. It is a method-specific percentage and is separate from how much material is in the vial. |
| Projected amount & content vs. label | The measured mass and the same figure as a percentage of the labelled amount. On blends, each component is reported separately as well as in total. |
| Endotoxins | The result in EU/mL against the stated limit. An endotoxin result is not a sterility result — they are different tests. |
| Heavy metals | Lead, arsenic, cadmium and mercury against USP <232> / ICH Q3D reference limits, where the report lists them. |
| Dates | The run date is when the sample was analysed; the generated date is when the document was issued. An amended certificate carries added results and a later generated date. |
Testing coverage varies by lot and by compound — do not assume a test that is not listed was performed. “Pass”, “Conforms” or “Below reference limits” refers to the laboratory’s stated criteria for that test only.
Common questions
How do I know a report matches the vial I have?
Match the lot number, not the product name. The lot is printed on your vial label and again in the top right of the certificate, beside the client name. If the two agree, that report is about your vial. If they do not, the report belongs to a different batch of the same product — check the card’s “Batch and report links” for earlier lots.
The number on my vial is not the number at the top of the report.
Those are two different things. The lot number (for example
NXP-RETA-02) identifies the batch and appears on your vial. The report number (for
example THPN-RETA-10-092126) is the laboratory’s reference for that particular
analysis. One lot can appear on more than one report.
What does the purity percentage actually measure?
It is the main peak as a share of the total integrated peak area at the stated wavelength, taken from the laboratory’s own integration of the chromatogram. It describes the proportion of detected material, not the amount of material in the vial — that is the measured content figure, reported separately in milligrams.
Why does content versus label read over 100%?
Vials are filled to meet or exceed the labelled mass, so the measured amount is commonly a little above the claim. A figure of 108.8% means the laboratory recovered 10.88 mg against a 10 mg label. A figure below 100% would mean the vial came in under its label.
Does every batch carry endotoxin and heavy metal testing?
Not every batch in this library. The panel has been expanding, and newer lots carry endotoxin and heavy metal results while older lots in the archive may not. Each card shows badges for the tests its current lot carries, and the Testing filter narrows the library to lots with each. The certificate itself is the record — if a test is not on the report, it was not part of that panel.
What does “Below reference limits” mean on heavy metals?
It means each element measured came in under the reference limit the laboratory compared it against — USP <232> / ICH Q3D on these reports. It is a result against a stated limit, not a statement that no metals were detectable.
Can I check a report with the laboratory directly?
Yes, and we would rather you did. Take the report number from the top right corner to the issuing laboratory’s own verification page and it will return its copy of the report. That confirms the result at its source instead of taking our word for it.
Why are sold-out lots still listed?
Because the vial may still be on your bench. Once a lot is published here it stays published, moved into “Batch and report links” on its product card when a newer lot takes over. Removing an old report would leave anyone holding that lot with nothing to check against.
My batch is not in the library.
Send us the product name, the labelled strength, the lot number from the vial and your order number, and we will locate the report for that batch or ask the laboratory for a copy. Contact us here.
Can’t find the exact match?
Send us the product name, labelled strength, lot number and order number, and we will track down the report for your batch.
All NexPept products are intended for laboratory research use only. Not for human or veterinary use.
Reading the evidence
What a certificate can tell you.
A certificate of analysis records what the laboratory measured in the sample it was given. Start by matching the sample to your vial, then read each result next to the method and the limit it was measured against.
1.Match the sample
Check the compound, the labelled strength and the lot number against your vial. A matching product name on its own does not establish a batch match.
2.Read the measurements
Purity, measured content and contaminant screens are separate results. Look at the units, the limit each is compared against, and any footnotes on the page.
3.Confirm the source
Check the run date and the generated date, then take the report number to the issuing laboratory and confirm the result at the source rather than with us.
| Report field | What to look for |
|---|---|
| Lot number | Printed top right of the report, beside the client name. It has to match the lot on your vial — this is the only field that ties the report to the vial in your hand. |
| Report number | The laboratory’s own reference for the run. It is not the same as the lot number, and it is what you quote when verifying the report with the lab. |
| Identity | Whether the peak measured is the named compound, confirmed against a reference standard. Purity without identity tells you the vial is clean, not what it is clean of. |
| HPLC purity | The main peak as a share of all integrated peak area, at the stated wavelength. It is a method-specific percentage and is separate from how much material is in the vial. |
| Projected amount & content vs. label | The measured mass and the same figure as a percentage of the labelled amount. On blends, each component is reported separately as well as in total. |
| Endotoxins | The result in EU/mL against the stated limit. An endotoxin result is not a sterility result — they are different tests. |
| Heavy metals | Lead, arsenic, cadmium and mercury against USP <232> / ICH Q3D reference limits, where the report lists them. |
| Dates | The run date is when the sample was analysed; the generated date is when the document was issued. An amended certificate carries added results and a later generated date. |
Testing coverage varies by lot and by compound — do not assume a test that is not listed was performed. “Pass”, “Conforms” or “Below reference limits” refers to the laboratory’s stated criteria for that test only.
Common questions
How do I know a report matches the vial I have?
Match the lot number, not the product name. The lot is printed on your vial label and again in the top right of the certificate, beside the client name. If the two agree, that report is about your vial. If they do not, the report belongs to a different batch of the same product — check the card’s “Batch and report links” for earlier lots.
The number on my vial is not the number at the top of the report.
Those are two different things. The lot number (for example
NXP-RETA-02) identifies the batch and appears on your vial. The report number (for
example THPN-RETA-10-092126) is the laboratory’s reference for that particular
analysis. One lot can appear on more than one report.
What does the purity percentage actually measure?
It is the main peak as a share of the total integrated peak area at the stated wavelength, taken from the laboratory’s own integration of the chromatogram. It describes the proportion of detected material, not the amount of material in the vial — that is the measured content figure, reported separately in milligrams.
Why does content versus label read over 100%?
Vials are filled to meet or exceed the labelled mass, so the measured amount is commonly a little above the claim. A figure of 108.8% means the laboratory recovered 10.88 mg against a 10 mg label. A figure below 100% would mean the vial came in under its label.
Does every batch carry endotoxin and heavy metal testing?
Not every batch in this library. The panel has been expanding, and newer lots carry endotoxin and heavy metal results while older lots in the archive may not. Each card shows badges for the tests its current lot carries, and the Testing filter narrows the library to lots with each. The certificate itself is the record — if a test is not on the report, it was not part of that panel.
What does “Below reference limits” mean on heavy metals?
It means each element measured came in under the reference limit the laboratory compared it against — USP <232> / ICH Q3D on these reports. It is a result against a stated limit, not a statement that no metals were detectable.
Can I check a report with the laboratory directly?
Yes, and we would rather you did. Take the report number from the top right corner to the issuing laboratory’s own verification page and it will return its copy of the report. That confirms the result at its source instead of taking our word for it.
Why are sold-out lots still listed?
Because the vial may still be on your bench. Once a lot is published here it stays published, moved into “Batch and report links” on its product card when a newer lot takes over. Removing an old report would leave anyone holding that lot with nothing to check against.
My batch is not in the library.
Send us the product name, the labelled strength, the lot number from the vial and your order number, and we will locate the report for that batch or ask the laboratory for a copy. Contact us here.
Can’t find the exact match?
Send us the product name, labelled strength, lot number and order number, and we will track down the report for your batch.
All NexPept products are intended for laboratory research use only. Not for human or veterinary use.