What the science says about Kojic Acid
Peer-reviewed research on Kojic Acid, summarised in plain language. Every study links to its record on PubMed so you can read it yourself.
Kojic Acid for hyperpigmentation
Some evidence for hyperpigmentation- Both studies that tested it directly found it helped fade dark patches
- A large review found it improved melasma, a common kind of dark patch
- In one clinical trial, adding kojic acid helped clear melasma better
- The most common side effect mentioned was mild skin irritation
10 studies
Efficacy and safety of topical agents in the treatment of melasma: What's evidence? A systematic review and meta-analysis.
Journal of cosmetic dermatology2023Meta-analysisPositive
A large review of many clinical trials found that kojic acid improved melasma and had a low rate of skin irritation.
Topical Treatments for Melasma: A Systematic Review of Randomized Controlled Trials.
Journal of drugs in dermatology : JDD2019Systematic reviewNeutral
This review listed kojic acid among topical treatments for melasma but did not report a specific result for it.
The Efficacy of Topical Cosmetic Containing Alpha-Arbutin 5% and Kojic Acid 2% Compared With Triple Combination Cream for the Treatment of Melasma: A Split-Face, Evaluator-Blinded Randomized Pilot Study.
Journal of cosmetic dermatology2025RCT30 participants2%Mixed
In a 30-person, 12-week study, a cream with kojic acid and alpha-arbutin had similar melasma scores, less return of melasma, and fewer side effects than a triple-combination cream.
Analytic assessment under ultraviolet light of actinic lentigines under bleaching treatment.
Journal of cosmetic dermatology2011RCT24 participantsPositive
A skin-applied formula with kojic acid and other ingredients gradually lightened age spots in 24 women over 3 months.
Different therapeutic modalities for treatment of melasma.
Journal of cosmetic dermatology2009RCT45 participantsPositive
In a 16-week study of 45 people with melasma, hydroquinone and kojic acid reduced dark patches, but both peels worked better.
Assessment of topical hypopigmenting agents on solar lentigines of Asian women.
Dermatology (Basel, Switzerland)2002RCT50 participants1%Neutral
In a study of 50 women, a formulation with kojic acid did not lighten sun spots, while faint, hidden discoloration responded better to the treatments.
Treatment of melasma using kojic acid in a gel containing hydroquinone and glycolic acid.
Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]1999RCT40 participants2%Positive
In a 12-week study of 40 women, a gel with kojic acid, glycolic acid, and hydroquinone cleared melasma better than the same gel without kojic acid.
Evaluating the tolerance and efficacy of laser-assisted delivery of tranexamic acid, niacinamide, and kojic acid for melasma: A single center, prospective, split-face trial.
Dermatologic therapy2022Clinical trial25 participantsPositive
In a 25-person, 12-week trial, adding a skin-applied mixture of kojic acid and two other ingredients to laser treatment improved melasma more than laser alone.
Effect of a Tranexamic Acid, Kojic Acid, and Niacinamide Containing Serum on Facial Dyschromia: A Clinical Evaluation.
Journal of drugs in dermatology : JDD2019Clinical trial1%Positive
In a 12-week study, a serum with kojic acid and two other ingredients improved dark patches, skin texture, and skin tone.
The use of chemical peelings in the treatment of different cutaneous hyperpigmentations.
Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]1999Clinical trial20 participants10%Positive
In a study of people with melasma, a peel with glycolic and kojic acid cleared or partly faded dark patches for most people.
Research context, not treatment advice. Studies are about the ingredient, not any one product.
How we grade research for hyperpigmentation