The Peptide Purity Index

Median independently-tested purity and median price for every research peptide we track — computed from vendor Certificates of Analysis, not marketing claims. The benchmark a price-only tracker can’t publish.

As of July 2026

105

compounds tracked

99.6%

median tested purity across compounds

158

vendor batches with tested purity

Compound	Vendors	Median purity	Purity range	Median $/mg
BPC-157	28 · 5 tested	99.3%	99.0%–99.8%	$4.27/mg
Tesamorelin	26 · 4 tested	99.5%	99.0%–99.9%	$7.00/mg
GHK-Cu	25 · 3 tested	99.8%	99.6%–>99.9%	$0.550/mg
Retatrutide	24 · 5 tested	99.8%	99.7%–99.8%	$4.36/mg
MOTS-c	23 · 3 tested	99.4%	99.0%–99.8%	$3.50/mg

How it’s computed. For each compound we take every vendor that clears our listing bar (a C trust grade or better), collapse to that vendor’s best $/mg, and report the median across vendors. Tested purity is the median of the purity reported on the Certificate of Analysis for the batch each vendor is currently shipping. Values that round to 100% are shown as “>99.9%” — analytical purity is never exactly 100%.

No vendor can pay to change its ranking here. Compare a single compound across every vendor on its price comparison page. For research use only.