Understanding why a few products are released to product-specific lab standards instead of a universal 99% RP-HPLC purity rule.
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Peptide Testing & Quality
Why Customers Ask About This
Most customers expect peptide purity numbers to be as high as possible, so it is understandable to pause when one product shows a lower purity percentage than another.
For many standard peptides, a very high RP-HPLC purity result is realistic and expected. But not every product behaves the same way in testing. Some compounds are more complex, more structurally sensitive, or are not single simple peptides at all. In those cases, using one blanket 99% rule across every product can be misleading rather than helpful.
That is why a small group of products are evaluated using product-specific release standards instead of a universal 99% threshold.
What “Purity By RP-HPLC” Actually Means
RP-HPLC is one of the main lab methods used to evaluate peptide purity. It is a very useful tool, but it is still a testing method with limits.
A purity number reported by RP-HPLC reflects how the sample separates under that specific method. That works very well for many straightforward peptides. But for more complex compounds, the result can be influenced by things like:
• peptide length
• structural complexity
• chemical modifications
• folding or conformational behavior
• closely related impurities that may separate imperfectly
• whether the product is a mixture rather than one single defined peptide
So when a customer sees a peptide testing below 99%, that does not automatically mean the product failed quality standards. It may simply mean that the correct standard for that product is different.
Our Approach
Pantheon does not use a one-size-fits-all purity rule for every item.
Most products can be reviewed against a very high purity expectation. But certain products are excluded from a blanket 99% RP-HPLC threshold because that standard is not the right fit for the compound being tested.
Instead, those products are released against a product-appropriate third-party specification based on the nature of the material and the way it behaves under laboratory analysis.
Peptides Currently Excluded From The Blanket 99% Threshold
CJC-1295 with DAC
CJC-1295 with DAC is not a simple unmodified peptide. The DAC portion changes how the molecule behaves and makes it harder to compare directly to a standard short linear peptide on a routine RP-HPLC test.
Current release standard:
• Third-party RP-HPLC purity specification: not less than 98%
Explanation:
CJC-1295 with DAC is a modified peptide, which makes it more analytically complex than a standard short peptide. Because of that, it is released against a product-specific third-party purity standard of 98% or higher, rather than a blanket 99% threshold.
IGF-1 LR3
IGF-1 LR3 is a much larger and more structurally complex peptide than most common products. Long peptides are generally more difficult to evaluate cleanly with a single routine RP-HPLC method, especially when closely related forms can behave similarly during testing.
Current release standard:
• Third-party RP-HPLC purity specification: not less than 90%
Explanation:
IGF-1 LR3 is a long, structurally complex peptide, so it is released against a product-specific third-party purity standard of 90% or higher rather than a blanket 99% threshold.
Cerebrolysin
Cerebrolysin is different from most products because it is not a single defined peptide compound. It is better understood as a peptide mixture.
Current release standard:
• Product-specific identity and composition standard
• Not evaluated using a blanket single-compound 99% RP-HPLC rule
Explanation:
Cerebrolysin is a peptide mixture rather than one single defined peptide, so a blanket 99% purity threshold is not the right standard for this product. Instead, it is reviewed against a product-appropriate testing standard focused on identity and composition consistency.
ACE-031
ACE-031 is also not a standard small peptide in the way many other catalog items are. It is a more complex biologic-style compound, which means the usual blanket small-peptide RP-HPLC expectation is not the right way to judge it.
Current release standard:
• Product-appropriate biologic/protein-style standard
• Not evaluated using a blanket small-peptide 99% RP-HPLC rule
Explanation:
ACE-031 is a more complex biologic-style compound, so it is not evaluated using the same blanket 99% purity threshold used for standard small peptides. It is reviewed using a product-appropriate quality standard instead.
Why We Do Not Simply Force Everything Into A 99% Rule
At first glance, a universal 99% requirement sounds cleaner and easier. But in practice, it can create confusion.
If a product is naturally more difficult to measure by routine RP-HPLC, then forcing it into a blanket 99% standard does not make the testing more honest. It can actually make the result less meaningful.
A product-specific release standard is often the more accurate and more transparent approach because it reflects what the compound actually is and how it should be evaluated.
What A Lower Number Does And Does Not Mean
A lower RP-HPLC purity number on one of these excluded products does not automatically mean:
• the product is low quality
• the batch failed testing
• the material is unsafe by default
• the lab made an error
• the result is worse than another product just because the percentage is lower
Instead, it usually means the product was reviewed under the correct testing standard for that specific compound.
A Practical Way To Review Results For These Products
When reviewing COAs for these products, it helps to compare the result to that product’s actual pass standard rather than to a universal number used for every item.
A simple review process is:
• confirm the product identity
• look at the purity result shown on the COA
• check the laboratory specification or pass threshold for that product
• determine whether the batch conformed to that product-specific standard
• avoid comparing a complex product directly to a simple peptide using only one number
This approach usually gives a more accurate picture of whether the product passed its proper release criteria.
Our Current Exclusion List
At this time, the products excluded from the blanket 99% purity threshold are:
• CJC-1295 with DAC
• IGF-1 LR3
• Cerebrolysin
• ACE-031
Important Note
This does not mean these products are untested. It means they are evaluated using the lab standard that best fits the product.
For example, some excluded products may still use RP-HPLC, but with a lower product-specific pass threshold. Others may be reviewed using a different identity or composition-based standard because a universal small-peptide purity rule is not scientifically appropriate.
Need Help Interpreting A COA?
If you are looking at a Certificate of Analysis and are unsure why one peptide shows a lower purity number than another, our team can help explain:
• what the reported purity result means
• what the lab’s pass standard was for that product
• whether the batch conformed to its release specification
• why that product may not be held to a blanket 99% threshold
We’re Here to Help
If you have questions about a specific product or batch, contact us and we’ll help you interpret the test result in plain English.
Disclaimer
All information provided here is for educational and informational purposes only. These products are not approved to diagnose, treat, cure, or prevent any disease. Product purity standards and release specifications may vary depending on the nature of the compound and the analytical method used. Always review the product-specific Certificate of Analysis and consult a qualified professional where appropriate.
