Arbutin

Arbutin is a tyrosinase-inhibiting brightening agent typically used around 1–2% (alpha-arbutin) or higher for beta-arbutin, and it is generally well-tolerated with low rates of stinging or erythema in clinical use. However, in highly reactive or eczema-prone skin, irritation can still occur—especially when combined with other actives (acids/retinoids) or in compromised barriers—so it is best classified as gentle but not inert. Safety Notes: In consumer skincare, arbutin is most often used in leave-on serums/creams, with low-end inclusion levels around 0.05–0.2% in brightening moisturizers and multi-active formulas where it is not a hero active. Mainstream OTC arbutin serums commonly fall around ~1–2%, while high-strength consumer-available “alpha-arbutin” booster serums are marketed and formulated up to about 10% (higher levels are uncommon due to diminishing solubility/stability and color/odor changes over time). Rinse-off products typically sit at the lower end because of short contact time.