Alpha Arbutin

A glycoside of hydroquinone that hydrolyses slowly in skin tissue to release hydroquinone — the most clinically proven skin-lightening compound — at lower concentrations and with less irritation than direct hydroquinone application. Inhibits tyrosinase, the enzyme controlling melanin synthesis. In-vitro mechanism is well-characterised; human clinical trial evidence is growing but remains thinner than the hydroquinone literature it references. Used at 1–2% in OTC formulas. Unlike hydroquinone, it is freely available in EU markets without prescription restrictions.