Overview

A fragment of type I collagen that signals to fibroblasts that collagen has been damaged, prompting them to make more. The palmitoyl tail is what lets it actually get through the skin barrier — a design detail many peptide cosmetics neglect.

Cosmetic IngredientEstablished cosmetic ingredient with published controlled human studies, including a comparison against retinol.

At a glance

Regulatory status	Established cosmetic ingredient with published controlled human studies, including a comparison against retinol.
Drug class	Lipidated pentapeptide — a collagen fragment conjugated to palmitic acid
Route	Topical
Half-life	Not applicable — topical
Evidence rating	3/5 Moderate Evidence rating 3 out of 5: Moderate Small or early-phase human trials, or good controlled topical human data.
Studied in	A 12-week double-blind split-face trial versus vehicle; a comparative study against retinol; multiple fibroblast and ex-vivo skin studies.

How it works

The KTTKS sequence is a subfragment of type I procollagen. Applied topically it acts as a feedback signal stimulating fibroblast synthesis of collagen I, collagen III, fibronectin and glycosaminoglycans. Palmitoylation greatly increases lipophilicity and stratum corneum penetration.

Evidence base

Rated 3 of 5 — Moderate. Small or early-phase human trials, or good controlled topical human data.

Among the best-supported topical cosmetic peptides, with a double-blind vehicle-controlled trial.

Benefits & potential uses

Bars indicate how well each claim is supported: three = strong human evidence, two = moderate, one = preliminary or preclinical.

Wrinkle and roughness improvement in controlled trials Moderate evidence

A 12-week double-blind trial showed significant improvement in wrinkle depth and skin roughness versus vehicle.
Comparable to retinol with better tolerance Moderate evidence

Comparative work suggests effects approaching retinol's with markedly less irritation.
Collagen and matrix stimulation Moderate evidence

Consistent fibroblast data showing upregulation of collagen and extracellular matrix components.
Designed for skin penetration Moderate evidence

The palmitoyl chain solves the delivery problem that limits many topical peptides.
Very well tolerated Strong evidence

Suitable for sensitive skin and usable alongside most actives.

Risks, cons & cautions

Bars indicate seriousness: three = serious or common, two = moderate, one = minor.

Modest effect sizes Minor

Real but incremental; it will not match procedural interventions.
Slow onset Minor

Meaningful changes take 8–12 weeks of consistent use.
Concentration varies widely between products Moderate evidence

Many products contain far less than the concentrations used in studies.
Industry-funded research Moderate evidence

Much of the evidence originates with ingredient suppliers.
Rare contact sensitivity Minor

Uncommon.

Who should avoid it

Known ingredient allergy

If used under medical supervision, monitor

None required

Regulatory & legal status

Lawful cosmetic ingredient.

Infographic

Matrixyl (Palmitoyl Pentapeptide-4) — benefits & risks at a glance Download SVG

Where to read further

We link to live literature searches rather than a frozen citation list, so you always see current results — including anything published after our last review.

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Related peptides in Skin & Cosmetic

Terms used on this page

Collagen Type I: Collagen type I is the dominant structural protein of tendon, bone, skin and scar, a triple-helical heterotrimer whose thick cross-linked fibrils carry tensile load.
Skin Barrier Function: Skin barrier function is the stratum corneum's capacity to restrict water loss outward and chemical entry inward, sustained by corneocytes embedded in ordered intercellular lipid lamellae.
Fibroblast: A fibroblast is the mesenchymal cell that produces and maintains connective tissue matrix, and which differentiates into a contractile myofibroblast during wound repair.
Glycosaminoglycans (GAGs): Glycosaminoglycans are long unbranched sugar chains of repeating disaccharides that hold water in the dermal ground substance and, except for hyaluronan, are sulfated and attached to core proteins.
Stratum Corneum: The stratum corneum is the outermost epidermal layer of dead, keratin-filled corneocytes in a lipid matrix, and it is the rate-limiting barrier for essentially every topical ingredient.
Lipidation and Fatty Acid Acylation: Lipidation is the covalent attachment of a fatty acid to a peptide, usually at a lysine side chain, creating reversible albumin binding that dramatically extends circulating half-life.

This page is educational information, not medical advice. It cannot account for your medical history, medications, or risk factors. Do not start, stop or change any treatment based on it. Speak to a qualified healthcare professional who knows your case.