Licorice Root ExtractvsMandelic Acid

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.

Mandelic acid (152 Da, the largest common AHA) exfoliates through calcium chelation and corneodesmosome disruption like other AHAs, but its large molecular size results in slower, more even epidermal penetration with reduced risk of hot-spot irritation and stratum corneum over-exfoliation. Its phenyl ring confers partial lipophilicity, enabling penetration into the pilosebaceous unit and follicular infundibulum—unlike purely hydrophilic glycolic and lactic acids. Within pores, mandelic acid exerts mild comedolytic effects by disrupting keratinocyte cohesion in the follicular epithelium, similar to salicylic acid. It demonstrates antibacterial activity against Cutibacterium acnes (Propionibacterium acnes) through membrane disruption. Mandelic acid also inhibits tyrosinase and reduces melanosome transfer to keratinocytes, providing brightening benefits. This profile makes it particularly suitable for acne-prone skin, hyperpigmentation, and darker skin tones (Fitzpatrick IV–VI) where gentler exfoliation minimizes post-inflammatory hyperpigmentation risk.