palmitoyl tetrapeptide-7
Pal-GQPR, palmitoyl-rigin, N-palmitoyl-glycyl-L-glutaminyl-L-prolyl-L-arginine, Pal-Gly-Gln-Pro-Arg
Palmitoyl tetrapeptide-7 is a palmitoylated version of rigin, a four-residue fragment (Gly-Gln-Pro-Arg) isolated from human immunoglobulin G in 1981. In cosmetics it is sold as an anti-inflammatory peptide said to suppress interleukin-6 release from skin cells, and it is the second component of a common two-peptide anti-wrinkle blend. There is a real biochemical literature on rigin, but a PubMed phrase search for the cosmetic derivative returns nothing at all.
Mechanism
Rigin (GQPR) was described by Veretennikova and colleagues as a phagocytosis-stimulating tetrapeptide recovered from human IgG, structurally and functionally analogous to tuftsin (Thr-Lys-Pro-Arg). Both share the Pro-Arg C-terminus required for tuftsin-like activity, and NMR with computational analysis characterised rigin's preferred fold as a type VII beta-turn. Dutta and colleagues showed that hydrophobic (lipid-modified) rigin analogues retained and in some cases amplified immunomodulatory activity in mice, including protection in a Plasmodium berghei challenge. Palmitoyl tetrapeptide-7 is structurally exactly that kind of hydrophobic rigin analogue.
The cosmetic mechanism claimed for the ingredient runs opposite to the published rigin pharmacology, and that tension deserves stating plainly. Suppliers describe it as reducing interleukin-6 output from keratinocytes and fibroblasts after ultraviolet exposure, lowering IL-6-driven matrix metalloproteinase expression, an anti-inflammatory framing. The primary literature describes rigin as an immunostimulant that enhances phagocytosis, in the tuftsin family. No published study reconciles these, and no peer-reviewed paper demonstrates IL-6 suppression by palmitoyl tetrapeptide-7 in human skin cells. The palmitoyl chain serves the usual purpose: giving a hydrophilic, arginine-bearing tetrapeptide enough lipophilicity to partition into the stratum corneum.
What the research shows
Veretennikova and colleagues isolated rigin from human IgG in 1981 and reported that it stimulated phagocytosis, characterising it as a second tuftsin-like tetrapeptide within the immunoglobulin molecule. Conformational work by Ashish and Kishore identified a type VII beta-turn as rigin's bioactive fold, supported by later high-temperature molecular dynamics simulation. Dutta and colleagues synthesised hydrophobic rigin analogues and reported enhanced immunomodulatory activity and protection against murine malaria, establishing that lipid modification of this scaffold yields biologically active molecules.
What is missing is any of that in skin. PubMed contains no record whatsoever mentioning palmitoyl tetrapeptide-7: no keratinocyte, fibroblast, ex vivo skin or human study. The claims made in retail contexts (reduced IL-6 secretion, reduced glycation, a stated percentage wrinkle-depth reduction) are traceable to supplier technical dossiers. A reader should treat the ingredient as plausible on chemical grounds and unevidenced on clinical grounds.
Evidence assessment
Preclinical only
A PubMed phrase search for 'palmitoyl tetrapeptide-7' returns zero records. This was checked directly and is the strongest such result in this set. There is no peer-reviewed human study of the ingredient, alone or in a formulation where its contribution can be isolated, and the efficacy data circulated for the two-peptide blend are unpublished supplier studies. What exists is a small, genuine biochemical literature on the parent peptide rigin: its isolation from IgG, its solution conformation, and the immunomodulatory activity of hydrophobic analogues in mice, none conducted in skin. That places the ingredient at the preclinical tier, and the underlying preclinical work does not support the anti-inflammatory claim made for it.
Tiers are applied consistently across the library and re-checked when new trials read out. Read the grading method.
Key studies
Rigin, another phagocytosis-stimulating tetrapeptide isolated from human IgG. Confirmations of a hypothesis Preclinical only
Identified Gly-Gln-Pro-Arg within human IgG and reported phagocytosis-stimulating activity, defining rigin as a tuftsin-like immunostimulant.
Characterization of a novel type VII beta-turn conformation for a bio-active tetrapeptide rigin. A synergy between theoretical and experimental results Preclinical only
Defined rigin's bioactive solution conformation as a type VII beta-turn, providing a structural basis for tuftsin-like receptor interactions.
Immunomodulatory potential of hydrophobic analogs of Rigin and their role in providing protection against Plasmodium berghei infection in mice Preclinical only
Lipid-modified rigin analogues retained immunomodulatory activity and conferred protection in murine malaria, showing hydrophobic derivatisation of this scaffold yields active molecules.
Folded conformation of an immunostimulating tetrapeptide rigin: high temperature molecular dynamics simulation study Preclinical only
Supported the beta-turn conformational assignment for rigin across simulated thermal conditions.
Safety
No safety signal has been reported for cosmetic use, and the Cosmetic Ingredient Review has assessed palmitoyl oligopeptides as a class without identifying concerns at use levels. One theoretical point is worth noting: if the palmitoyl amide were cleaved in skin to release free rigin, the released peptide belongs to a family with documented immunostimulant activity. There is no evidence this occurs at cosmetically relevant exposures and no clinical reports of immune-related effects from topical use. This is a topical ingredient; it has not been evaluated for injection and no licensed injectable preparation exists. Human pregnancy and lactation data are absent.
Regulatory status
| Jurisdiction | Status |
|---|---|
| United Kingdom | Permitted as a cosmetic ingredient under the UK Cosmetics Regulation (retained Regulation (EC) No 1223/2009); not listed in any prohibited or restricted annex. A Cosmetic Product Safety Report and responsible person are required. No MHRA medicines authorisation. |
| United States | Not an FDA-approved drug and not covered by an OTC drug monograph; marketed as a cosmetic ingredient. Cosmetic ingredients other than colour additives are not pre-approved under the FD&C Act as amended by the Modernization of Cosmetics Regulation Act 2022, but structure-or-function claims can render a product an unapproved drug. |
| WADA (sport) | Not named on the WADA Prohibited List. Topical cosmetic use raises no anti-doping issue. |
Questions
Its peptide core, Gly-Gln-Pro-Arg, is rigin, a fragment identified in 1981 within human immunoglobulin G. The cosmetic ingredient is made synthetically with a palmitic acid chain added to the N-terminus; it is not derived from human material.
No peer-reviewed study demonstrates this. A PubMed search for the ingredient returns no records at all. The claim originates in supplier technical literature. Notably, the published biology of the parent peptide runs the other way: rigin was characterised as a phagocytosis-stimulating immunostimulant in the tuftsin family, not as an anti-inflammatory agent.
Yes; the other is palmitoyl tripeptide-1. The efficacy figures quoted for that blend come from unpublished supplier studies of the combination, so neither peptide's individual contribution is established in the peer-reviewed literature.
No safety concerns have emerged from cosmetic use, and palmitoyl oligopeptides have been reviewed as a class without adverse findings at use levels. It is a topical cosmetic ingredient only, has not been evaluated for injection, and there are no human pregnancy or lactation data.