Kojic Acid: effective % & pH 코직애씨드
⏱ 1 min read
⚡ Quick answer: Kojic Acid: effective concentration 1–2% in leave-on formulas, though the EU, UK and Japan cap it at 1% in face and hand products, optimal pH 4.0–5.5, evidence Moderate. Effective but more sensitising than arbutin or niacinamide. Introduce it slowly, and never onto already-irritated skin.
How much Kojic Acid actually works? Here's the dosage, pH and evidence — the formulator-level read behind the % on a Korean label.
| Effective % | 1–2% in leave-on formulas, though the EU, UK and Japan cap it at 1% in face and hand products |
|---|---|
| Optimal pH | 4.0–5.5 |
| Evidence | Moderate |
| Onset | 8–12 weeks |
What the % on the label really means
Effective but more sensitising than arbutin or niacinamide. Introduce it slowly, and never onto already-irritated skin.
⚠️ Ceiling: The cap came out of safety reviews covering systemic and endocrine concerns, not only skin sensitisation — though it is the more sensitising of the common brighteners too.
Kojic Acid guide →How Kojic Acid works →
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✍️ Written & reviewed by the KoreaPlus Editorial team — dermatologist-informed, cosmetic-science researched & source-cited. Last reviewed: 2026-08-23.
General educational information using cosmetic structure-function wording — not medical advice. Always patch-test new actives. © KoreaPlus.