Myristoyl Nonapeptide-3

Myristoyl Nonapeptide-3 is a lipopeptide used in anti-aging products, typically at low concentrations (generally well under 0.1–0.5%), and peptides as a class are usually well-tolerated in controlled use. However, the myristoyl (fatty-acyl) modification can increase skin interaction and, in highly reactive or eczema-prone patients, lipopeptides can occasionally sting or trigger irritation even when not classic sensitizers. Given limited large-scale irritation datasets specific to this exact peptide and the need to err toward patient safety, I rate it as gentle with low but non-zero irritation potential. Safety Notes: In consumer leave-on anti-aging/firming serums and eye creams, Myristoyl Nonapeptide-3 is typically used at very low levels consistent with peptide supplier guidance and market INCI practices (often ~0.001–0.01% active), with the lowest observed commercial uses around 0.0005% in multi-peptide blends. High-strength OTC formulations (peptide-focused serums/ampoules marketed for intensive use) are observed up to about 0.05% as an individual peptide active or as part of concentrated peptide complexes, above which cost, solubility, and diminishing returns generally limit real-world use. This ingredient is predominantly found in leave-on products; rinse-off applications are uncommon and generally sit at the low end due to short contact time.