Quick answerSome evidence
Matrixyl is a brand name for signal peptides (often palmitoyl pentapeptide-4 / Matrixyl 3000). Small trials suggest they help improve the look of fine lines. Common in multi-peptide serums.
You will see Matrixyl inside blends such as The Ordinary Multi-Peptide + HA. For a full ranking, see best peptide serums.