palmitoyl tripeptide-1
C16-GHK, N-palmitoyl-GHK, N-palmitoyl-glycyl-L-histidyl-L-lysine, Pal-GHK, Pal-Gly-His-Lys, palmitoyl oligopeptide (former INCI usage), palmitoyl-glycyl-histidyl-lysine
Palmitoyl tripeptide-1 is the tripeptide glycyl-histidyl-lysine (GHK) with a 16-carbon palmitic acid chain on its N-terminus, added to make the water-loving peptide partition into the lipids of the stratum corneum. It is one of two peptides in a widely sold anti-wrinkle blend and is used in leave-on cosmetics. Almost all the biology attributed to it is really the biology of GHK, and the only indexed human study tested it in a two-ingredient regimen.
Mechanism
The design rationale is straightforward pharmaceutics rather than novel biology. Free GHK and its copper complex are charged and hydrophilic, and human skin penetration studies show they are largely retained in the stratum corneum. Attaching a palmitoyl chain raises lipophilicity so the molecule partitions into the intercellular lipid lamellae of the stratum corneum and can traverse them, in the same way that other lipidated cosmetic peptides such as palmitoyl tetrapeptide-7 do. Once delivered, the GHK moiety is proposed to act as a matrikine: a small extracellular matrix fragment that signals tissue damage and prompts fibroblasts to synthesise collagen types I and III, fibronectin and glycosaminoglycans.
One consequence of the design is rarely discussed and worth stating precisely. GHK's copper coordination depends on its free N-terminal amine, which supplies one of the donor atoms in the square-planar copper(II) site along with the deprotonated peptide nitrogen and the histidine imidazole. Acylating that amine with palmitic acid blocks it. Palmitoyl tripeptide-1 is therefore not simply a better-absorbed GHK; it is a chemically distinct molecule whose copper-binding behaviour differs from, and is expected to be substantially weaker than, that of GHK-Cu. Any mechanistic account that leans on copper-dependent lysyl oxidase activation transfers poorly to the lipidated derivative.
What the research shows
There is no isolated efficacy literature for this compound. Palmitoyl tripeptide-1 is almost always formulated alongside palmitoyl tetrapeptide-7 in a widely licensed cosmetic blend, and published evaluations assess the finished product, typically over eight to twelve weeks, using cutometry, profilometry, standardised photography and expert grading. These studies are sponsored by ingredient suppliers or brands, are rarely independently replicated, and by design cannot attribute any observed effect to palmitoyl tripeptide-1 rather than to its partner peptide, the vehicle, or the moisturisation and photoprotection that accompany any consistent skincare regimen.
What the peer-reviewed literature does contain is a body of work on the parent tripeptide and on the delivery problem the lipidation was meant to solve. Mortazavi's 2025 review of topical GHK as an anti-wrinkle peptide is explicit that penetration and formulation stability remain the limiting constraints, and that this is the reason derivatisation and encapsulation strategies proliferate. Skin penetration studies by Mazurowska and by Hostynek characterise how poorly the underivatised complex crosses the barrier, and liposomal carrier work by Dymek pursues the same goal by a different route. The reasonable conclusion is that palmitoyl tripeptide-1 is a well-motivated cosmetic ingredient with a plausible mechanism, sitting on a thin and commercially generated efficacy base. It is not a therapeutic agent and there is no evidence it does anything for wounds, injuries or any medical condition.
Evidence assessment
Limited evidence
The underlying GHK copper co-ordination chemistry is settled and the in vitro biology is genuine. The cosmetic ingredient is not well evidenced. A PubMed phrase search for 'palmitoyl tripeptide-1' returns exactly one record: Wang and colleagues (2026), which enrolled 30 participants and tested the peptide in a timed combination with baicalin, so its individual contribution cannot be separated; two co-author affiliations are commercial biotechnology companies despite a declaration of no conflicts. There is no independent placebo-controlled trial of the peptide as a single agent, and the percentage figures quoted for the two-peptide blend come from unpublished supplier dossiers. Solid mechanism plus thin, non-isolated human data is what 'limited' describes.
Tiers are applied consistently across the library and re-checked when new trials read out. Read the grading method.
Key studies
Structure of the Glycyl-L-histidyl-L-lysine--copper(II) complex in solution Preclinical only
Established the square-planar Cu(II) co-ordination geometry of GHK, the chemical basis for describing the peptide as a copper carrier.
Stimulation of sulfated glycosaminoglycan synthesis by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+ Preclinical only
GHK-Cu increased sulfated glycosaminoglycan synthesis in fibroblast culture.
The tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+ stimulates matrix metalloproteinase-2 expression by fibroblast cultures Preclinical only
GHK-Cu upregulated MMP-2, indicating the peptide promotes matrix turnover rather than net accumulation alone.
Collagen stimulating effect of peptide amphiphile C16-KTTKS on human fibroblasts Preclinical only
A palmitoylated cosmetic peptide self-assembles into nanostructures above a critical concentration, and this changes its interaction with fibroblasts.
Targeting Circadian Rhythm for the Regulation of Skin Collagen Metabolism Preclinical only
Daytime baicalin plus night-time palmitoyl tripeptide-1 improved skin luminance (+16.29%), nasolabial fold depth (-36.35%) and firmness (R2 +24.35%) in 30 female participants; no peptide-only arm, so the peptide's individual contribution is not isolable.
Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data Preclinical only
Collates reported gene-expression and tissue-remodelling actions of GHK-Cu; useful as an index of the literature but authored by the peptide's principal proponent and not an independent systematic assessment.
Topically applied GHK as an anti-wrinkle peptide: Advantages, problems and prospective Preclinical only
Skin penetration and formulation stability remain the principal barriers to topical GHK efficacy, motivating lipidated and encapsulated derivatives.
Biological activities of selected peptides: skin penetration ability of copper complexes with peptides Preclinical only
Copper-peptide complexes show limited penetration through skin barrier layers, constraining topical bioavailability.
Human skin retention and penetration of a copper tripeptide in vitro as function of skin layer towards anti-inflammatory therapy Preclinical only
Most applied copper tripeptide is retained in the upper stratum corneum rather than reaching viable dermis.
Liposomes as Carriers of GHK-Cu Tripeptide for Cosmetic Application Preclinical only
Liposomal encapsulation is pursued as a means of improving GHK-Cu delivery into skin, reflecting the unmodified peptide's penetration limits.
Safety
The Cosmetic Ingredient Review expert panel has assessed palmitoyl oligopeptides as a group for cosmetic use without identifying concerns at use levels. Reported adverse effects are limited to occasional irritation or contact dermatitis, which in finished products is at least as likely to arise from preservatives, fragrance or surfactants as from the peptide. Systemic absorption is expected to be negligible and no reproductive or systemic toxicity signals have emerged from topical use. This is a topical cosmetic ingredient: it has not been evaluated for injection and no sterile injectable preparation exists as a licensed product. Avoid contact with the eye itself. Human pregnancy and lactation data are absent, and absence of data is not evidence of safety.
Regulatory status
| Jurisdiction | Status |
|---|---|
| United Kingdom | Permitted as a cosmetic ingredient under the UK Cosmetics Regulation (the retained version of Regulation (EC) No 1223/2009); not listed in the prohibited or restricted annexes. Products require a Cosmetic Product Safety Report and a designated responsible person. No MHRA marketing authorisation as a medicine. |
| United States | Not an FDA-approved drug and not covered by any OTC drug monograph; marketed as a cosmetic ingredient. Under the Federal Food, Drug, and Cosmetic Act as amended by the Modernization of Cosmetics Regulation Act 2022, cosmetic ingredients other than colour additives are not pre-approved, but products making structure-or-function claims can be treated as unapproved drugs. |
| WADA (sport) | Not named on the WADA Prohibited List. Topical cosmetic use raises no anti-doping issue. |
Questions
No. Palmitoyl tripeptide-1 is copper-free GHK with a palmitic acid chain on the N-terminus. GHK-Cu (copper tripeptide-1) is the copper(II) complex of the bare tripeptide, with no lipid tail. They share the GHK core but differ in both the metal and the lipid, and most published bioactivity data were generated with the copper complex.
Not directly. The commonly cited percentages come from supplier studies of the two-peptide blend that pairs this ingredient with palmitoyl tetrapeptide-7, and those studies are not in the peer-reviewed literature. The single indexed human study using palmitoyl tripeptide-1 tested it alongside baicalin in a timed regimen, without a peptide-only comparison.
GHK is small, charged and water-loving, which makes it poorly suited to crossing the lipid-rich stratum corneum. The C16 chain makes the molecule amphiphilic so it can partition into skin lipids. The trade-off, shown for related lipopeptides, is that the molecule also self-assembles, which changes how it behaves rather than simply delivering more of the same peptide.
No signal has emerged from cosmetic use, and the Cosmetic Ingredient Review has assessed palmitoyl oligopeptides as a class without identifying concerns at use levels. It is a topical cosmetic ingredient only; it has never been evaluated for injection and no licensed injectable form exists.
It is better at getting into skin, which is a different claim from being more effective. The palmitoyl chain was added specifically to solve GHK's penetration problem. But acylating the N-terminal amine blocks one of the atoms GHK uses to bind copper, so palmitoyl tripeptide-1 is unlikely to deliver copper the way GHK-Cu does. Whether that trade-off is net positive has not been tested head to head in humans.
Not as a single agent, and none in the indexed literature. Published human evaluations test finished cosmetic formulations that combine it with palmitoyl tetrapeptide-7 and other actives, and are sponsored by ingredient suppliers or brands. Those studies cannot tell you what palmitoyl tripeptide-1 contributes on its own. Every citation that survives verification for this ingredient is in vitro or a review.
It should not be. It is a cosmetic-grade topical ingredient. There are no injectable safety data, no human pharmacokinetics, and cosmetic manufacturing carries no sterility or endotoxin requirements comparable to those for parenteral products.
There is no human evidence that it does. The wound-healing literature attached to this family of compounds concerns the parent tripeptide GHK and its copper complex, mostly in animals and cell culture. Palmitoyl tripeptide-1 is an anti-ageing cosmetic ingredient and has not been tested for wound repair in people.