Kojic Acid

CAS Number:

501-30-4

Chemical / IUPAC Name:

5-Hydroxy-2-(hydroxymethyl)-4H-pyran-4-one

INCI Name:

 Kojic Acid

Molecular Formula:

 C6H6O4

Molecular Weight:

 142.11 g/mol

EC Number:

207-922-4

Other Names:

5-Hydroxy-2-(hydroxymethyl)-4-pyrone, Kojic Acid

Uses:

Kojic Acid is a natural organic compound and a powerful tyrosinase inhibitor, making it one of the most popular skin-lightening and brightening agents in cosmetics .

· Skin Care & Cosmetics: Primarily used in skin brightening creams, serums, lotions, and soaps to reduce hyperpigmentation, dark spots, melasma, freckles, and post-inflammatory hyperpigmentation (acne scars) .

· Mechanism: It works by inhibiting the production of tyrosinase, an enzyme responsible for converting tyrosine into melanin (the pigment that darkens skin) .

· Preservative & Antioxidant: Exhibits antioxidant properties and can function as a preservative in some formulations, though this is a secondary use .

· Food Industry: Originally discovered as a byproduct of fermented foods (like sake), it is also used in some food applications to prevent enzymatic browning .

Origin

Kojic Acid is a naturally-derived compound produced by several species of fungi, especially Aspergillus oryzae (used in Japanese sake fermentation), during the aerobic fermentation of carbohydrates like rice, sweet potatoes, or corn. It can also be produced synthetically for commercial purposes .

What does Kojic Acid do in a formulation?

• Tyrosinase Inhibitor / Skin Lightening Agent: Reduces melanin production, lightening dark spots and evening skin tone .
• Antioxidant: Neutralizes free radicals that cause skin aging .
• Chelating Agent: Binds with metal ions, which contributes to its preservative and antioxidant functions .
• Preservative: Helps protect formulations from microbial growth (in some cases) .

Safety Profile:

· General Hazard Classification: Considered safe for topical use in cosmetics at recommended concentrations .

· Concentration Limits: Typically used at 1-4% in cosmetic formulations. Higher concentrations may increase irritation risk .

· Irritation & Sensitization: Can cause contact dermatitis and skin irritation in some individuals, especially at higher concentrations. It is recommended to perform a patch test before use .

· Photosensitivity: May increase skin sensitivity to UV radiation. Sunscreen use is strongly recommended when using products containing Kojic Acid .

· Stability: Kojic Acid is sensitive to heat, light, and air, which can cause it to oxidize and turn yellow/brown, reducing efficacy. Formulators often use stabilizers or derivatives (like Kojic Acid Dipalmitate) for better stability .

· Regulatory Status: Approved for use in cosmetics in most countries, with varying concentration limits. Banned or restricted in some regions (e.g., Japan has stricter regulations) .

Technical profile: