K4 Elite
K4 Elite
A lipidated tetrapeptide (palmitoyl-Gly-Gln-Pro-Arg) studied in dermal fibroblast and keratinocyte systems for cytokine-associated signaling, most often as one component of multi-peptide topical formulations.
Palmitoyl tetrapeptide-7 is the tetrapeptide Gly-Gln-Pro-Arg conjugated to palmitic acid. It is also encountered in older literature and on some ingredient listings under its former INCI name, palmitoyl tetrapeptide-3, and under the trade name Rigin [1][2].
As with other lipidated cosmetic peptides, the palmitoyl chain is a delivery modification: it raises lipophilicity so the molecule partitions into stratum corneum lipid lamellae, a property the free tetrapeptide does not have [1].
The evidence base here is materially thinner than for the peptides it is usually formulated with. Most published human data come from multi-peptide blends, and a large share of the frequently quoted cytokine numbers originate in supplier technical documentation rather than peer-reviewed work - a limitation this entry states plainly rather than working around [1][2][3].
The proposed mechanism reported in the cosmetic-science literature is that the Gly-Gln-Pro-Arg sequence interacts with interleukin-1-beta-associated signaling and modulates NF-kB pathway activation, with reduced output of pro-inflammatory mediators including interleukin-6 in dermal fibroblast and keratinocyte systems [1][4].
This mechanism is described as proposed rather than established. The receptor-level target has not been identified in peer-reviewed work, and the peptide is characterized functionally by cytokine readouts rather than by direct target engagement [1][4].
Gorouhi and Maibach reviewed controlled ex vivo and in vivo efficacy studies of topical peptides in aged skin and grouped the field into signal peptides, enzyme-inhibitor peptides, neurotransmitter-inhibitor peptides and carrier peptides, placing palmitoyl tetrapeptide-7 among the signal peptides. The review is explicit that study quality across the class is uneven and that few peptides have been tested as isolated actives [1].
Li and colleagues evaluated a multi-peptide topical eye serum containing acetyl hexapeptide-8, palmitoyl tetrapeptide-7, palmitoyl tripeptide-1 and dipeptide-2, applied twice daily for 28 days in participants with periorbital fine lines, using instrumental and graded wrinkle measures as endpoints. Because four peptides were present, the design does not permit attribution to any single component [3].
Cell-based reports in the cosmetic-science literature describe reductions in interleukin-6 output in resting and stimulated fibroblast cultures at micromolar peptide concentrations, with DHEA used as a comparator active in some of that work. Much of this dataset derives from supplier technical documentation and has not been independently replicated in peer-reviewed publications [4].
The Cosmetic Ingredient Review panel compiled composition, use-concentration, penetration and toxicology data for palmitoyl oligopeptides as a class, including this peptide, as part of a formal safety assessment [2].
Combinations examined in the research literature. Descriptive only — not a recommendation to combine compounds.