Tetrapeptide-30

Tetrapeptide-30 is a synthetic signaling peptide used in low concentrations (typically well under 1%) for brightening/anti-inflammatory support, and peptides as a class have low rates of irritant reactions in clinical and consumer use. It is not pH-dependent and lacks the keratolytic or solvent properties that commonly drive stinging and barrier disruption. Rare sensitivity is still possible (especially in eczema patients or when paired with other actives/preservatives), but the ingredient itself is generally very gentle at typical use levels. Safety Notes: Tetrapeptide-30 is a potent leave-on depigmenting/brightening peptide typically used at very low levels; commercial serums/creams often sit around ~0.001–0.01%, with the low end appearing in multi-peptide or “supporting-actives” brightening formulas. Higher-strength OTC specialty dark-spot serums have been marketed up to ~0.05% (commonly by using a higher active-load peptide solution), while higher than this is uncommon due to cost, diminishing returns, and stability/solubility limits; rinse-off usage is rare and generally stays at the lower end given short contact time.