When you see a research peptide advertised at "99% purity," what does that number actually mean — and why does it matter? This guide explains it in plain terms.
What purity measures
Purity is the percentage of material in a vial that is the intended peptide, as opposed to impurities such as truncated or deletion sequences and residual synthesis reagents. 99% purity means 99% of the peptide content is the target compound.
How purity is measured
The standard method is High-Performance Liquid Chromatography (HPLC), which separates a sample's components and quantifies each as a percentage. The main peak is the target peptide; smaller peaks are impurities.
Why it matters for research
In laboratory research, impurities can confound results. Higher purity means more reproducible, reliable data — which is why research-grade peptides are typically specified at 98–99%+.
Purity vs identity
Purity (how much is the target) differs from identity (whether it is the correct compound). Identity is confirmed separately by mass spectrometry.
At Peptide Pal
Every batch is verified to 99%+ purity by third-party HPLC. Browse our research peptides.
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