Compare peptide purity across brands using real third-party lab test results from Peptigrity. Select a peptide to see how different vendors stack up.
Select a peptide to compare purity across brands.
Peptide purity is one of the most important quality indicators. Higher purity means fewer impurities, degradation products, and potential contaminants. Third-party lab testing by independent laboratories provides the most reliable purity data - more trustworthy than vendor-provided certificates.
Common purity testing methods include HPLC (High-Performance Liquid Chromatography) and mass spectrometry. HPLC is the industry standard for determining peptide purity as a percentage.
HPLC separates a peptide sample into its individual components and measures the proportion that is the target peptide versus impurities - synthesis byproducts, truncated sequences, degradation products, and residual solvents. The result is expressed as a percentage: 99% purity means 99% of the sample is the target peptide.
| Purity Range | Classification | Typical Use Case |
|---|---|---|
| ≥ 98% | High purity | Quantitative research, sensitive assays |
| 95-97.9% | Standard research grade | General research applications |
| 90-94.9% | Below standard | Screening, preliminary research only |
| < 90% | Low purity / suspect | Not suitable for most applications |
Mass spectrometry measures the molecular weight of the peptide and compares it to the expected theoretical mass. A match (typically within ±1 Dalton) confirms that the vial contains the correct compound. HPLC alone cannot distinguish between two different peptides that happen to elute at similar retention times - mass spectrometry resolves this blind spot. For a full explanation, see the how to read peptide lab test results guide.
Lab test results in this tool come from 3 sources:
All results are linked to the original lab report documentation. For guidance on commissioning your own independent test, see how to get your peptides independently tested.
A vial with 95% purity delivers less active peptide per dose than one at 99% purity - meaning you need slightly more product to achieve the same effective dose. Over a multi-month protocol, this difference compounds. The cost-per-dose calculator helps compare the effective cost per milligram of active peptide. Combining purity data from this tool with pricing data from the cost calculator provides the clearest picture of actual value.
Purity varies by compound, batch, and testing date - no single brand consistently tops every peptide across all tests. Select a peptide in the tool above to see the current rankings based on independent lab data. Results are sorted by purity from highest to lowest.
A vendor-provided COA is a starting point, not proof. COAs can be reused across batches, fabricated, or generated from a single good batch while subsequent batches go untested. Independent third-party testing provides stronger verification. See the red flags in COAs guide for how to evaluate vendor-provided documentation.
Research-grade peptides should test at ≥ 95% purity by HPLC. High-quality products routinely achieve 98-99.5%. Purity below 95% indicates significant impurity content that may affect research outcomes. The peptide purity standards guide covers acceptable thresholds in detail.
HPLC is a relative measurement influenced by column chemistry, mobile phase gradient, detection wavelength, and integration parameters. Two labs testing the same sample may report slightly different values (typically within 1-2 percentage points). This tool displays the lab name alongside each result so you can compare results from the same lab directly.
Peptigrity adds new lab test results as testing is completed - typically several new results per month. The tool displays the test date for each result so you can assess recency.
Yes. Verified lab reports from accredited third-party laboratories can be submitted through Peptigrity. Submissions are reviewed for authenticity before publication. See how to get your peptides independently tested for guidance.
This calculator is for educational and informational purposes only and does not constitute medical advice. Peptides discussed may be investigational compounds not approved by the FDA for human use. Always consult a qualified healthcare provider. Peptigrity is an independent review platform and does not sell, endorse, or recommend specific products or vendors.