{
  "id": "palmitoyl-pentapeptide-4",
  "idVersion": 1,
  "ingredient": "Palmitoyl Pentapeptide-4 (pal-KTTKS)",
  "route": "topical",
  "grade": "limited",
  "gradeLabel": "Limited",
  "claim": "The held evidence is specific to Palmitoyl Pentapeptide-4 (pal-KTTKS), not to peptides as a class.",
  "caveat": "The permeation study used ex-vivo hairless-mouse skin and detected neither KTTKS nor pal-KTTKS in receptor solution. The clinical literature named by the review concerns Palmitoyl Pentapeptide-4 specifically.",
  "published": "2026-09-19",
  "sources": [
    {
      "url": "https://pubmed.ncbi.nlm.nih.gov/25143811/",
      "journal": "Biomol Ther (Seoul)",
      "year": 2014,
      "n": null,
      "design": null,
      "duration": null,
      "percentages": [],
      "outcome": "ex-vivo hairless-mouse skin distribution, dermal stability",
      "finding": "Ex-vivo full-thickness hairless-mouse skin: neither KTTKS nor pal-KTTKS reached receptor solution. KTTKS was absent from the measured skin layers; pal-KTTKS was detected in stratum corneum and epidermis, with a small dermal amount. This is animal-skin distribution evidence, not human permeation.",
      "formulation": "KTTKS, palmitoyl-KTTKS"
    },
    {
      "url": "https://doi.org/10.3390/cosmetics4020016",
      "journal": "Cosmetics",
      "year": 2017,
      "n": null,
      "design": "Narrative review",
      "duration": null,
      "percentages": [],
      "outcome": "narrative review of topical peptide treatments",
      "finding": "Narrative review names Palmitoyl Pentapeptide-4 as the well-researched molecule and cites Robinson et al. 2005 for a controlled study in photoaged human facial skin. It does not establish a result for peptides as a class.",
      "formulation": "Palmitoyl Pentapeptide-4"
    }
  ],
  "peopleReport": null
}