Peptide effective concentrations and the penetration challenge | Skincare University

※ The information in this section is based on Japanese cosmetics regulations (Pharmaceutical and Medical Device Act / 薬機法). Ingredient classifications, permitted concentrations, and labeling requirements may differ in your country or region.

LEVEL 3 Complete Guide to Peptides

For peptides to work, they need adequate concentration and skin penetration — hurdles higher than expected.

Trace-amount signal molecules

Effective at 0.001% to 2% because they work through signals, not concentration.

The 500Da Rule

Below 500Da passes the stratum corneum more easily. Tripeptides (~300Da) and tetrapeptides (~400Da) penetrate well.

Palmitoylation

Fatty acid attachment increases lipophilicity for barrier passage.

Purity matters

99% vs 50% purity differ dramatically. Concentration disclosure is essential.

KAIAN develops evidence-based peptide skincare products.
Feel free to reach out with questions.

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