Identity a synthetic lipopeptide — the pentapeptide KTTKS (5 amino acids, < 40 aa → peptide), a matrikine fragment of the C-terminal propeptide of type I procollagen, conjugated to palmitic acid (C16) to aid skin penetration (unmodified KTTKS is hydrophilic, ~562 Da, and penetrates poorly). KTTKS identified 1993 (Katayama); Matrixyl launched 2000 by Sederma. ## Development & history - The active KTTKS sequence was identified in 1993 (Katayama et al.) as a collagen-propeptide fragment that stimulates matrix synthesis. To make it usable on skin, the French active-ingredient house Sederma attached a palmitoyl tail and launched Pal-KTTKS as Matrixyl in 2000 — described as the first peptide active designed for anti-ageing cosmetics (Lintner & Peschard, 2000).
- The line then expanded commercially: Matrixyl → Matrixyl 3000 (a two-peptide system) → Matrixyl Synthe'6. Sederma is part of Croda. Like Argireline, it has only ever been a cosmetic ingredient, not a drug. ## Variants - Matrixyl = single peptide Pal-KTTKS (Palmitoyl Pentapeptide-4).
- Matrixyl 3000 = two-component: Palmitoyl Tripeptide-1 (Pal-GHK) + Palmitoyl Tetrapeptide-7 (Pal-GQPR) — different signals (collagen + IL-6 downregulation).
- Matrixyl Synthe'6 = Palmitoyl Tripeptide-38. ## Mechanism (as proposed) KTTKS is a matrikine — a fragment released during type I collagen processing that acts as a feedback signal. Matrixyl is proposed to mimic this signal: once the palmitoyl tail carries it into the dermis, KTTKS is proposed to bind fibroblast surface receptors (TGF-β-linked signalling) and stimulate extracellular-matrix synthesis (collagen, fibronectin, HA), with the effect described as self-limiting. Much of this is characterised in vitro; the extent and consistency of the effect on intact human skin is more modest than the cell-culture figures suggest.