Caprooyl Tetrapeptide-3

Caprooyl Tetrapeptide-3 is a lipopeptide signal peptide used in anti-aging/hair-support products, typically at very low concentrations (often well under 1%) in leave-on formulas, and peptides of this class are generally well tolerated in clinical/consumer use. While irritation is uncommon, the caproyl (fatty-acyl) modification and leave-on exposure mean a small subset of highly reactive or eczema-prone patients can experience stinging or dermatitis, so it is not truly inert. Given the low typical dose but nonzero risk in compromised skin, a gentle (0.3) score best matches patient-safety expectations. Safety Notes: Caprooyl Tetrapeptide-3 is most often used in leave-on anti-aging/firming serums and eye products at very low active levels because it is typically supplied as a diluted solution (often in glycerin/water) and is effective in the ppm-to-low-0.01% range in commercial formulas. In mass-market products the true neat-peptide level commonly lands around ~0.0001–0.01%, while higher-strength consumer “peptide booster”/specialty treatments can reach ~0.05–0.1% neat active when the supplier blend is heavily dosed. Rinse-off use is uncommon and generally sits at the low end due to brief contact time and cost.