Allantoin

Allantoin is 尿囊素 (niào náng sù) in Chinese — the same characters in Simplified and Traditional. It's a gentle repair ingredient that speeds skin-cell renewal and calms irritation, a decades-old staple in dermatology.

Both are repair ingredients, different mechanisms. Allantoin mainly drives cell proliferation; centella asiaticoside leans more anti-inflammatory and barrier-strengthening. Many soothing products contain both. For post-procedure or mild sensitivity, allantoin alone is enough; heavier inflammation may need centella alongside.

Yes. It's extremely safe with no practical dose ceiling — provided the concentration stays under 2% and the formula carries no other irritants. If you're already on retinol or acids, alternate days instead of layering, to avoid stacked irritation.

Not necessarily. 0.5%–2% is the standard effective range, and going higher doesn't meaningfully multiply results — it mostly adds cost and can feel less pleasant. A sensible concentration paired with other repair ingredients works better.

Allantoin is a repair ingredient, not an anti-inflammatory drug. Redness from a damaged barrier needs hydration support (hyaluronic acid, ceramides) alongside it; acne-driven inflammation may call for niacinamide or salicylic acid. Adjust the overall routine — don't lean on one ingredient.

Keep it somewhere cool and dry, away from direct sunlight, and try to finish it within 3–6 months of opening. If it degrades — darker color, off smell — throw it out rather than keep using it.