Licorice Root ExtractvsZinc Oxide

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.

Zinc oxide particles sit on the skin surface and primarily scatter and reflect UV radiation across the full UVA (320–400 nm) and UVB (280–320 nm) spectrum via Rayleigh and Mie scattering. At nano scale, zinc oxide also absorbs UV photons and undergoes semiconductor band-gap excitation, converting UV energy to heat—a mechanism similar to organic chemical filters. It provides the broadest single-ingredient UV coverage available. Beyond photoprotection, zinc oxide exerts anti-inflammatory effects by inhibiting NF-κB activation, reducing pro-inflammatory cytokine release (TNF-α, IL-6), and modulating Toll-like receptor signaling. It supports barrier repair by promoting occludin and zonula occludens-1 expression in tight junctions. Zinc ions have mild antimicrobial activity against Staphylococcus aureus and Candida species. These properties underlie its use in diaper rash creams, wound care, and post-procedure skincare. Zinc oxide does not penetrate intact stratum corneum when formulated as micronized or nano particles.