Testing panels explained
What HPLC-only, HPLC + MS, and full QC panels each answer — and what each one leaves open.
When a vendor says "third-party tested," the question is: tested for what? A Certificate of Analysis can include one assay or a dozen. The panel of tests on a certificate determines what questions are answered and, equally important, which questions remain open. This guide compares the four panel tiers we see across vendors on this site, using the same testing labels defined on our testing reference.
Comparison matrix
| Test | HPLC Only | HPLC + MS | + Net Content | Full QC |
|---|---|---|---|---|
| HPLC Purity | Yes | Yes | Yes | Yes |
| LC-MS/MS Identity | — | Yes | Yes | Yes |
| Net Peptide Content | — | — | Yes | Yes |
| Endotoxin | — | — | — | Yes |
| Sterility | — | — | — | Yes |
| Residual Solvents | — | — | — | Yes |
| Heavy Metals | — | — | — | Yes |
| Fentanyl Screen | — | — | — | Optional |
Each panel in detail
HPLC Only
Answers: How much of the detected material is the target peak.
- Whether the material is the claimed compound (no identity confirmation)
- How much of the vial is actual peptide vs. non-peptide weight
- Whether anything outside the method's detection scope is present
- Whether the sample is sterile or free of endotoxin
- Whether heavy metals or residual solvents are present
This is the minimum viable certificate. It tells you one thing: the proportion of the target peak among detectable chromatographic peaks. It does not confirm that the target peak is the compound you think it is, and it says nothing about safety-relevant contaminants.
HPLC + LC-MS/MS
Answers: How pure the detected material is and whether the measured mass is consistent with the expected compound.
- How much of the vial is actual peptide vs. counterions, moisture, or residual solvents
- Whether the sample is sterile or free of endotoxin
- Whether heavy metals, residual solvents, or fentanyl are present
- Whether the net peptide content matches the label claim
Adding LC-MS/MS identity to HPLC purity closes the most important gap left by HPLC alone: it confirms that the target peak is actually the claimed compound. This is the panel we consider the minimum for a credible purity claim. Without identity confirmation, a 99% purity result could be 99% pure something else.
HPLC + LC-MS/MS + Net Peptide Content
Answers: Purity, identity, and how much of the total material is actual target peptide rather than non-peptide weight.
- Whether the sample is sterile or free of endotoxin
- Whether heavy metals, residual solvents, or fentanyl are present
Net peptide content is the missing piece between purity and real-world dosing. A vial labeled "5mg BPC-157" with 99% HPLC purity might contain 3.5mg of actual peptide if the remaining weight is counterions and moisture. Net peptide content testing (via amino acid analysis or qNMR) reveals this. This is the panel that lets you compare what you pay for against what you actually get.
Full QC Panel
Answers: Purity, identity, net content, microbiological safety, chemical contaminants, and process residue in the tested sample.
- Whether untested analytes or contaminants are present
- Whether other lots match this one
A full QC panel covers the questions a researcher actually needs answered before working with a material. It includes identity, purity, content, microbiological safety (endotoxin and sterility), and chemical contaminants (residual solvents and heavy metals). Some vendors also include a fentanyl screen. This is the strongest documentation profile a vendor can provide, and it scores highest in our Testing Breadth subscore.
Why purity alone is not enough
An HPLC purity result tells you the proportion of the target peak among detectable peaks. It does not tell you that the target peak is the compound on the label — that requires identity confirmation by LC-MS/MS, as explained in purity is not identity. And it does not tell you how much of the powder in the vial is actual peptide versus counterions, moisture, and residual solvents — that requires net peptide content testing.
A vendor with a 99% HPLC purity result and nothing else has documented one fact about the tested sample. A vendor with a full QC panel has documented purity, identity, content, microbiological safety, and chemical contamination. The difference matters not because the first vendor is necessarily dishonest, but because the first vendor has not answered the questions the second one has.
How panel breadth affects scores
Testing Breadth is a subscore within the Purity & Testing category, worth 10 points out of the category's 100. Each distinct test type on a vendor's COAs adds points up to the 10-point ceiling. A vendor running only HPLC earns 1-2 points; a vendor running HPLC plus LC-MS/MS identity earns 3-4; a vendor with a full QC panel earns the maximum. The scoring methodology guide describes the exact calculation.
Panel breadth also affects the Value category. The testing-to-price ratio subscore rewards vendors whose testing investment justifies their price. A vendor charging premium prices with an HPLC-only panel scores lower on value than a vendor charging the same price with a full QC panel — because the second vendor's price is backed by deeper evidence.
What a complete panel still cannot prove
Even a full QC panel documents one sample from one lot on one date. It is not a catalog-wide guarantee, and it does not prove that every vial from that batch matches the tested sample. The missing test guide explains what each individual assay answers and leaves open. The batch-specific vs catalog COAs guide explains why a single undated certificate is weaker than per-lot documentation.
Where to go next
What a missing test leaves open
Each assay answers one question. A missing test is not a failure and not proof of anything.
Purity is not identity
Why a 99% HPLC result does not mean the vial contains the labeled mass.
Full scoring methodology
Exact weights, subscore calculations, and how testing breadth feeds into scores.
Compare vendors on testing
A checklist you can run on any two vendor pages, evidence before price.
Research & Informational Use Only. PeptideScores does not sell, endorse, or facilitate the purchase of any compound for human use. All compounds referenced are intended for laboratory research purposes only. We review vendors; we do not provide dosing guidance, medical advice, or treatment recommendations.