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Kojic Acid

INCI: Kojic Acid
Also known as: 5-Hydroxy-2-(hydroxymethyl)-4H-pyran-4-one
BrighteningbrighteningbiotechModerate evidencePregnancy safe
76
Skinlumis Rating
Comedogenic
0/5
Irritancy
3/5
Best applied
PM
Effective range
1%–4%
How It Works

A fungal-fermentation by-product (Aspergillus oryzae, the koji fungus used in sake brewing) that inhibits melanin production and copper-chelates the tyrosinase enzyme.

Chelates copper at the active site of tyrosinase, halting melanin synthesis. Also a mild antioxidant scavenging hydroxyl radicals.

pH Range
3.0–6.0
Benefits
  • Reduces dark spots
  • Brightens overall tone
  • Fades melasma
  • Antioxidant action
Proven For

What the evidence supports.

MelasmaHyperpigmentationSun damage
Best For
  • Normal
  • Combination
Avoid If
  • Highly sensitive skin
  • Compromised barrier
Layering Order
4/10

Mid-routine serum or treatment step.

Max Safe Concentration
4%

Concentration range in well-formulated products: 1%–4%

Seasonal Use

Best in autumn/winter; reduce frequency in high-UV summer to minimise irritation risk.

Nutrition Connection

Produced during sake, soy sauce, and miso fermentation.

Skin Signals When You Need It

No specific deficiency signals tracked for this ingredient.

For Estheticians & Professionals

Sensitisation increases over time; cycle 12 weeks on / 4 weeks off for sensitive clients.

Notable Research
  • Lim 1999, kojic acid + glycolic acid superior to either alone for melasma
Clinical Evidence

The research behind Kojic Acid.

4 peer-reviewed studies

Every claim on this page traces to published research. Findings below are drawn from randomized trials and systematic reviews, each links to the study on PubMed.

Randomized Controlled Trial
Vitamin C showed comparable efficacy to hydroquinone for melasma treatment.
Espinal-Perez LE, Moncada B, Castanedo-Cazares JP
International Journal of Dermatology, 2004
View Study →
Randomized Controlled Trial
Niacinamide inhibits melanosome transfer to keratinocytes, reducing hyperpigmentation by up to 35%.
Hakozaki T, Minwalla L, Zhuang J et al.
British Journal of Dermatology, 2002
View Study →
Randomized Controlled Trial
Azelaic acid comparable to hydroquinone for hyperpigmentation with superior safety across all Fitzpatrick types.
Balina LM, Graupe K
International Journal of Dermatology, 1991
View Study →
Randomized Controlled Trial
Daily sunscreen use reduced photoaging markers by 24% over 4.5 years compared to discretionary use.
Hughes MCB, Williams GM, Baker P, Green AC
Annals of Internal Medicine, 2013
View Study →
Pairs Well With
Alpha ArbutinNiacinamideVitamin C (Ascorbyl Glucoside)
Conflicts With
Retinol (in sensitive skin)
Your Skin Compatibility

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