Quick Comparison

EGF (Epidermal Growth Factor)Licorice Root Extract
Typical ConcentrationConcentrations vary by product (typically measured in ppm or sh-oligopeptide-1 percentage). Applied once or twice daily. Best used after procedures or on aging skin. Apply before oils/occlusives. Store in refrigerator for stability.Concentrations vary; glabridin at 0.1-0.4% is the most active brightening component. Full extract at 1-4%. Apply morning and/or night. Safe for all skin types. Often combined with niacinamide and arbutin for enhanced brightening.
ApplicationTopical (serum, cream, ampoule). Apply to clean skin. Temperature-sensitive — some products require refrigeration.Topical (serum, cream, toner). Very stable in formulation. Compatible with most active ingredients.
Research Papers10 papers10 papers
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Mechanism of Action

EGF (Epidermal Growth Factor)

EGF binds EGFR/ErbB1 on keratinocytes and fibroblasts, triggering dimerization and autophosphorylation. Activates MAPK/ERK (Ras-Raf-MEK-ERK) and PI3K/AKT pathways, promoting proliferation, migration (actin reorganization, focal adhesion turnover), and differentiation. Upregulates cyclin D1, inhibits p27. Stimulates fibroblast collagen types I/III and hyaluronic acid via HAS2. In wound healing, accelerates re-epithelialization via keratinocyte migration and reduces scarring via TGF-beta modulation. For anti-aging, promotes cellular renewal and extracellular matrix production. Theoretical cancer concern from EGFR's growth role — topical EGF has not been shown to penetrate to basal layer or systemic circulation significantly.

Licorice Root Extract

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.

Risks & Safety

EGF (Epidermal Growth Factor)

Common

Very well-tolerated.

Serious

Theoretical concern about promoting growth of pre-existing skin cancers (unproven but debated).

Rare

Mild irritation.

Licorice Root Extract

Common

Very well-tolerated.

Serious

None documented topically. Oral licorice (glycyrrhizin) can elevate blood pressure, but topical use does not have this effect.

Rare

Allergic contact dermatitis.

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