129 Application of Kojic Acid in Treatment of Melasma Supplementary Material 2. Detailed search strategy. Electronic database and other research resources Search strategy MEDLINE (PubMed) (“kojic acid”[All Fields]) AND (“melanosis”[MeSH Terms] OR “melanosis”[All Fields] OR “melasma”[All Fields] OR “Chloasma”[All Fields]) (“kojic acid”[All Fields]) AND (“adverse effects”[MeSH Subheading] OR (“adverse”[All Fields] AND “effects”[All Fields]) OR “adverse effects”[All Fields] OR “Drug-Related Side Effects and Adverse Reactions”[All Fields]) BVS “kojic acid” AND (melasma OR chloasma OR melanosis) “kojic acid” AND (“adverse effects” OR “adverse event” OR “adverse drug reaction”) Embase (“kojic acid” OR (kojic AND (“acid”/exp OR acid) AND (“chloasma”/exp OR chloasma) AND (“melanosis”/exp OR melanosis) “kojic acid” AND (“adverse event” OR “adverse drug reaction”) Escopus “kojic acid” AND (melasma OR chloasma OR melanosis) “kojic acid” AND (“adverse effects” OR “adverse event” OR “adverse drug reaction”) Cochrane Library Kojic acid AND Melasma Kojic acid Melasma Google Scholar, Open Gray, the ISRCTN registry, ClinicalTrials, the Australian New Zealand Clinical Trials Registry, the World Health Organization International Clinical Trials Registry Platform, the EU Clinical Trials Register, the American Academy of Dermatology, the British Association of Dermatologists, the European Academy of Dermatology Annual Meeting, and the Annual Meeting of the Australasian College of Dermatologists Kojic acid AND Melasma Kojic acid Melasma

Supplementary Material 3 List of reasons for the exclusion of studies, after reading them in full (=18). Author/Year Title Exclusion reasons Truchuelo Jimenez Jaen, 2014 Assessment of the efficacy and tolerance of a new combination of retinoids and depigmenting agents in the treatment of melasma. Unevaluated intervention of interest. Iurassich Santoro Rossi, 2010 A case of chemical vitiligo due to kojic acid. Unevaluated population of interest. Tejera-Vaquerizo García-Gavín, 2019 Allergic contact dermatitis due to kojic acid. Unevaluated population of interest Serra-Baldrich Tribô Camarasa, 2007 Allergic contact dermatitis from kojic acid. Unevaluated population of interest. Ikeno, 2000 Clinical evaluation of a cream containing kojic acid and licorice extract on hyperpigmentation of the skin. No access to full text. Harada, 2000 Clinical evaluation of whitening cream containing kojic acid and oil-soluble licorice extract for senile pigment fleckle on the face. Unevaluated population of interest. Oresajo Yatskayer, 2009 Comparative evaluation for the efficacy and tolerance of two skin products containing either hydroquinone or emblica extract with kojic acid in female subjects with facial dyschromia. Unevaluated population of interest. Nakagawa Kawai Kawai, 1995 Contact allergy to kojic acid in skin care products. Unevaluated population of interest. Gold Biron, 2011, Efficacy of a novel hydroquinone-free skin-brightening cream in patients with melasma. Unevaluated intervention of interest. Park et al.2021 ,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. No access to full text. Al-Dhalimi Yasser, 2021 Evaluation of the efficacy of fractional erbium-doped yttrium aluminum garnet laser-assisted drug delivery of kojic acid in the treatment of melasma: A split face, comparative clinical study. No access to full text. Burnett et al.2010 ,Final report of the safety assessment of kojic acid as used in cosmetics. Not interventional study design. Cotellessa et al.1999 ,Glycolic acid and kojic acid: A new combined treatment. No access to full text. Madhogaria Ahmed, 2010 Leucoderma after use of a skin-lightening cream containing kojic dipalmitate, liquorice root extract and Mitracarpus scaber extract. Unevaluated intervention of interest. ()130 JOURNAL OF COSMETIC SCIENCE