Kojic acid
Kojic acid is a substance produced by certain moulds during fermentation, such as Aspergillus oryzae, known as koji from sake and soy sauce production. In skincare it is used to care for uneven tone and the look of darker spots.
It suits you if darker patches have stayed after summer, post-blemish marks are slow to fade or your skin tone looks uneven.
How kojic acid works and what the evidence shows
Kojic acid may reduce the activity of tyrosinase, an enzyme involved in melanin production. Most clinical data, however, come from combinations with other brightening ingredients. So you cannot judge how kojic acid works in a specific product from the ingredient list alone.
What EU regulation says
In the EU, cosmetics may contain no more than 1% kojic acid, and only in face and hand products. The limit was set by Commission Regulation (EU) 2024/996, based on an assessment by the Scientific Committee on Consumer Safety (SCCS). Non-compliant products may not be placed on the market from 1 February 2025, and from 1 November 2025 they may no longer be made available on the market at all.
How to find it on an ingredient list
In the INCI list, look for Kojic Acid. There is also a derivative, Kojic Dipalmitate, which is more stable and behaves differently. Kojic acid is often combined with niacinamide, vitamin C or gentle PHA acids.
How to use it in your routine
Apply a kojic acid serum after toner and before moisturiser. Patch test on a small area before first use. Always use SPF in the morning: without UV protection, caring for dark spots makes little sense. If you also use retinal, azelaic acid or exfoliating acids, avoid introducing all these actives at the same time. For sensitive skin, using them in separate routines or on different days is generally preferable, as combining them may increase irritation.
What to watch out for
Kojic acid can cause irritation or contact allergy in some people. If your skin is very reactive, you have rosacea or eczema, or your skin is irritated right now, choose different care. Show a dermatologist any spot that changes, grows or bleeds.
Kojic acid products at VIONE
- Sungboon Editor Kojic Acid Niacinamide Brightening Ampoule – a brightening serum with kojic acid and niacinamide, supported by a gentle PHA, turmeric, glutathione and vitamin C. Fragrance-free.
Frequently asked questions
Kojic acid, tranexamic acid or arbutin?
All three are used to care for uneven tone, but they work in different ways. Kojic acid and arbutin both target tyrosinase. Tranexamic acid works through a different pathway and tends to be well tolerated. If your skin is on the sensitive side, it is often easier to start with arbutin or tranexamic acid, for example in Dr.Althea Melaclear Cream. One brightening product in your routine is enough.
You will find the full selection in Brightening and pigmentation.