OtherPeptideEvidence B2 cited

Palmitoyl Pentapeptide-4

Matrixyl

aka Matrixyl · Pal-KTTKS · palmitoyl pentapeptide

A signal peptide research describes as stimulating collagen I, III, and IV synthesis in skin fibroblasts.

Molecular wt

802.1g/mol

Formula

C39H75N7O10

CAS

214047-00-4

PubChem

9897237

Sequence

One-letter5 residues

KTTKS

Three-letter

Palmitoyl-Lys-Thr-Thr-Lys-Ser (Pal-KTTKS)

Read this before quoting the sequence

A pentapeptide (Lys-Thr-Thr-Lys-Ser, a subfragment of type I procollagen) N-terminally conjugated to palmitic acid to make it lipophilic enough to penetrate the stratum corneum. Marketed cosmetically as Matrixyl. INCI name 'Palmitoyl Pentapeptide-4'; formerly designated Palmitoyl Pentapeptide-3.

Source ↗

Mechanism of action

Palmitoyl Pentapeptide-4 works by mimicking the natural peptides involved in the skin's healing process. It stimulates the production of collagen types I, III, and IV, which are crucial for maintaining skin structure and elasticity. This peptide penetrates the skin barrier and signals fibroblasts to increase collagen synthesis, leading to improved skin firmness and reduced appearance of wrinkles.

What the evidence actually shows

Grade B

There are several human clinical trials that demonstrate the efficacy of Palmitoyl Pentapeptide-4 in reducing wrinkles and improving skin texture. These studies generally show positive outcomes, but more large-scale, long-term studies are needed to fully understand its effects and safety profile.

Regulatory status

Status

Cosmetic ingredient, not a medicine. Permitted for use in cosmetic products; it is not approved, and has not been submitted for approval, as a drug in any jurisdiction.

Clinical stage

Not a drug development programme. Human evidence consists of small cosmetic efficacy trials.

licensed

Palmitoyl Pentapeptide-4 is licensed for use in cosmetic products in the UK, as it is considered safe and effective for topical application.

Source ↗

Dosing — what backs each figure

Palmitoyl pentapeptide-4 (pal-KTTKS, sold as Matrixyl) is a cosmetic ingredient, not a drug, and has one good controlled human study: 3 ppm in a moisturiser applied twice daily for 12 weeks in 93 women, which improved wrinkle appearance versus vehicle. A '2-5%' figure describes how much of a diluted supplier blend goes into a formula, not how much peptide is on the skin - reading it as peptide concentration overstates the studied level by thousands of times.

ClinicalApproved labelling or a published human trial

3 ppm (0.0003%) pal-KTTKS in a moisturiser base, applied topically twice daily for 12 weeks, versus the same moisturiser without peptide on the opposite side of the face
93 Caucasian women aged 35-55, 12-week double-blind placebo-controlled split-face randomised study · topical
Robinson LR et al. Topical palmitoyl pentapeptide provides improvement in photoaged human facial skin. Int J Cosmet Sci 2005;27:155-60 ↗

Commonly circulatedNot established by any study

Dose: 2-5% concentration
Frequency: 1-2x daily

Why this isn't evidence
The only controlled human study used 3 ppm of the peptide - about 0.0003%, roughly seven to seventeen thousand times lower than '2-5%' - and the 2-5% figure is almost certainly the recommended use level of a dilute commercial trade blend (which contains only around 100 ppm of active peptide), not the peptide concentration; only the once-or-twice-daily application frequency matches the trial.

This figure is shown because it is what circulates and what people search for — not because it is supported. Cycle lengths in particular tend to be convention copied between compounds rather than anything derived from a compound's own pharmacokinetics.

Handling and storage

No compound-specific stability data exists

No peer-reviewed or regulatory stability data for the raw ingredient was located. As a cosmetic ingredient it is supplied already formulated into finished products, whose storage is governed by the finished-product manufacturer, not by peptide-vial conventions. Lyophilised/reconstituted stability fields do not meaningfully apply. General peptide handling still applies — reconstitute gently, keep it cold, keep it dark — but any specific figure you see quoted for this compound elsewhere is someone's assumption, not a measurement.

→ Reconstitution walkthrough → Reconstitution calculator

Safety

Commonly reported

·Mild skin irritation
·Redness

Rarely reported

·Severe allergic reaction

Contraindications

·Known allergy to cosmetic peptides

Drug interactions

·No known drug interactions

Reported combinations

Reported as synergistic

·Vitamin C
·Hyaluronic Acid

Combination claims in this dataset are largely unsourced and should be treated as folk knowledge until a citation appears beside them.

References (2)

Robinson LR, Fitzgerald NC, Doughty DG, Dawes NC, Berge CA, Bissett DL. (2005) Topical palmitoyl pentapeptide provides improvement in photoaged human facial skin ↗
Int J Cosmet SciPMID 18492182DOI
12-week double-blind, placebo-controlled, split-face randomised study in 93 Caucasian women aged 35-55. The product tested was a moisturiser containing 3 ppm pal-KTTKS versus the same moisturiser without it; pal-KTTKS was well tolerated and gave significant improvement versus control.
Aruan RR, Hutabarat H, Widodo AA, Firdiyono MTCC, Wirawanty C, Fransiska L. (2023) Double-blind, Randomized Trial on the Effectiveness of Acetylhexapeptide-3 Cream and Palmitoyl Pentapeptide-4 Cream for Crow's Feet ↗
J Clin Aesthet DermatolPMID 36909866
Eight-week double-blind randomised trial in 21 Indonesian women aged 26-55 comparing acetylhexapeptide-3 cream and palmitoyl pentapeptide-4 cream for crow's feet. Very small trial.

Data provenance

Chemistry and citations on this page were checked against primary sources on 2026-08-14. Values that could not be verified were left blank rather than filled with a plausible guess.

Could not verify
storage.lyophilized, storage.reconstituted, storage.lightSensitive, reconstitution.solvent, regulatory.wada

Research use only

This profile is educational reference material. It is not medical advice, not a prescription, and not an endorsement of self-administration. Compounds discussed here are research chemicals and most are not approved for human therapeutic use.

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