LEVEL 3 Complete Guide to Peptides
KAIAN R&D Team | |
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.
References
Key peer-reviewed sources behind the scientific statements in this article.
- Gorouhi F, Maibach HI. Role of topical peptides in preventing or treating aged skin. Int J Cosmet Sci. 2009;31(5):327–345. PubMed
- Bos JD, Meinardi MM. The 500 Dalton rule for the skin penetration of chemical compounds and drugs. Exp Dermatol. 2000;9(3):165–169. PubMed
- Robinson LR, Fitzgerald NC, Doughty DG, Dawes NC, Berge CA, Bissett DL. Topical palmitoyl pentapeptide provides improvement in photoaged human facial skin. Int J Cosmet Sci. 2005;27(3):155–160. PubMed
This article is reference information about cosmetic ingredients and does not guarantee efficacy. Figures and test results vary by condition.