Glycyrrhetinic Acid

Glycyrrhetinic acid (licorice-derived) is primarily used as an anti-inflammatory/soothing agent, typically at low leave-on concentrations (~0.1–1%). Human repeat-insult patch testing and clinical use generally show low irritation rates, but a small subset of reactive or eczema-prone patients can experience stinging or contact dermatitis to licorice derivatives or the full formula. Given its generally good tolerability yet non-zero sensitization potential in highly sensitive skin, it fits best as a gentle (not inert) ingredient. Safety Notes: In mass-market leave-on soothing/anti-redness, after-sun, and barrier-repair products, glycyrrhetinic acid is commonly used as a low-level anti-irritant/anti-inflammatory at ~0.01–0.1%, with some rinse-off cleansers sitting at the very low end due to short contact time. Higher-strength OTC brightening/spot-corrector and post-procedure “calming” serums/creams marketed to consumers are typically formulated around 0.3–0.5% and can reach about 1.0% in specialty products, with higher levels being constrained by solubility and irritation risk in leave-on formats.