Kojic acid is a fungal-derived compound used at concentrations around 1% to inhibit melanin production, helping to reduce hyperpigmentation, melasma, and uneven skin tone. It works by chelating copper at the active site of tyrosinase, a key enzyme in melanogenesis.
| Reported effect | How often | Notes |
|---|---|---|
| Contact dermatitis / skin irritation | Common | Redness, itching, and stinging are the most frequently reported reactions, especially at higher concentrations or with prolonged use. |
| Erythema (redness) | Common | Transient redness at the application site, often dose-dependent. |
| Allergic contact sensitization | Uncommon | Kojic acid is recognized as a potential sensitizer with repeated exposure. |
| Increased photosensitivity | Uncommon | Skin may become more sensitive to UV; sunscreen use is advised during treatment. |
| Contact leukoderma / depigmentation | Rare | Loss of pigment with prolonged or high-concentration use has been reported infrequently. |
| Severe systemic or hepatic effects | Very rare | Concerns raised in some animal studies have not been substantiated for topical human use at typical concentrations. |
Frequencies reflect typical cosmetic use reported in the literature, not a guarantee for your skin.