Allantoin

A naturally occurring compound (found in comfrey root and produced endogenously in most organisms) with documented keratolytic, wound-healing, and soothing properties. It promotes skin cell proliferation and accelerates healing of minor irritations and abrasions — used in clinical wound care formulations. Has mild keratolytic activity at higher concentrations, softening rough skin and helping shed dead cells more smoothly than exfoliants alone. Exceptional tolerability — one of the most widely used soothing agents in cosmetics, particularly in products designed for post-procedure skin, sensitive skin, and barrier repair. Effective at 0.5–2%; FDA-recognised as a skin protectant at these concentrations.