Alpha ArbutinvsLicorice Root Extract

Alpha arbutin (4-hydroxyphenyl-alpha-D-glucopyranoside) is a glycosylated hydroquinone with glucose bound to the para position. Alpha-glucosidase and other glycosidases slowly hydrolyze the bond, releasing hydroquinone in controlled low concentrations—avoiding peak levels that cause irritation and ochronosis. Released hydroquinone inhibits tyrosinase by competing with tyrosine and through copper chelation at the catalytic center, reducing L-DOPA to dopaquinone conversion. The alpha anomer provides greater stability and skin penetration than beta arbutin. May also inhibit melanosome maturation. Gradual release creates sustained low-dose tyrosinase inhibition that brightens over 8-12 weeks with minimal side effects.

Glabridin competitively inhibits tyrosinase by binding copper active site (CuA, CuB), blocking tyrosine to L-DOPA hydroxylation and DOPA to dopaquinone oxidation. Also inhibits tyrosinase-related protein 1 (TRP-1). Liquiritin disperses existing melanin via melanosome transfer inhibition and autophagy pathway upregulation in keratinocytes. Glycyrrhizin inhibits COX-2 and 5-lipoxygenase, reducing prostaglandin and leukotriene production. Multi-mechanism brightening: tyrosinase inhibition, melanin dispersal, anti-inflammation. Unlike hydroquinone, no melanocyte cytotoxicity — suitable for long-term use and all skin tones. Glabridin has free radical scavenging antioxidant activity. Glycyrrhizin's 11-beta-HSD inhibition has minimal systemic effect with topical use.