Understand the source comparison
Are US vs China peptides meaningfully different in purity?
At the research-use retail tier, yes — US-manufactured peptides verified through ISO 17025 third-party labs consistently test at 99%+ HPLC purity, while China-sourced retail peptides show wider variance of 95–99%. The impurity profile behind those numbers also
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- At the research-use retail tier, yes — US-manufactured peptides verified through ISO 17025 third-party labs consistently test at 99%+ HPLC purity, while China-sourced retail peptides show wider variance of 95–99%. The impurity profile behind those numbers also differs substantially. Top-tier Chinese API manufacturers can match US quality, but their product does not typically reach retail research channels.