Peptide Purity: What 98% vs 99% Actually Means
Research peptides are usually sold with a purity figure — 95%, 98%, 99%+ — but the number alone does not tell you much without context. Here is what peptide purity actually measures and why the gap between 98% and 99% can matter. (Research-use context only.)
What purity measures
Peptide purity is typically determined by HPLC and expressed as the percentage of the sample that is the target peptide, versus impurities like truncated sequences, deletion products, and residual reagents. A 99% figure means roughly 1% of the material is something other than the intended peptide.
98% vs 99%: does 1% matter?
For many research applications the difference is meaningful, because the impurities are not random — they can be closely related peptide byproducts that behave differently in an assay. Higher purity reduces that variability. That said, a verified 98% is worth more than an unverified 99%: the number is only as trustworthy as the COA and method behind it. How to read the COA →
Why the method matters as much as the number
An HPLC purity percentage should come with a chromatogram, and identity should be confirmed separately by mass spectrometry — a high purity number means little if the molecule itself is not verified. HPLC vs mass spec →
What to look for
Treat purity as one line on a complete, batch-level, third-party COA — not a standalone marketing claim. Every product in the Life Link Research catalog reports batch purity with supporting documentation.
Research use only. Peptides and related materials referenced are intended for in-vitro laboratory research only — not for human or veterinary use, diagnosis, treatment, or consumption. This guide is general educational information, not medical or purchasing advice.
