Myristoyl Pentapeptide-17

Myristoyl Pentapeptide-17 is a lipidated signal peptide primarily used in lash/brow and cosmetic serums at low concentrations, and peptides of this class are generally well-tolerated with low rates of irritant reactions in routine use. The myristoyl (fatty acyl) modification can very occasionally contribute to stinging or follicular irritation in highly reactive or eczematous skin, but it is not a pH-dependent active and lacks the irritancy profile of acids, retinoids, or strong preservatives. Given typical leave-on use and sensitive-skin safety considerations, it fits best as very gentle rather than inert. Safety Notes: In consumer lash/brow serums and eye-area leave-on products, Myristoyl Pentapeptide-17 is commonly used at very low active levels (often ~0.0005–0.01%) because it is typically supplied as a dilute solution and is effective at low dosing; the lowest market observations are around 0.0001% in multi-peptide blends and budget formulas. High-strength, consumer-available lash/brow serums that position around “maximum peptide” dosing can reach ~0.05–0.10% active, which is near the practical upper end for solubility, cost, and sensory/stability constraints in leave-on aqueous/hydroalcoholic systems. It is rarely used meaningfully in rinse-off formats; the observed range is primarily for leave-on lash/brow and periocular products.