Also known as: 5-18-02-00516, BRN 0120895, EINECS 207-922-4, 5-Hydroxy-2-(hydroxymethyl)-4-pyrone, UNII-6K23F1TT52 (+2 more)
INCI: KOJIC ACID
Kojic Acid (CAS 501-30-4) is a cosmetic active ingredient functioning as Tyrosinase inhibitor; chelates copper at the enzyme's active site blocking both. NOAEL 2 mg/kg bw/day (PDF-verified against ToxValDB ECHA IUCLID); EU Regulation 1223/2009 status: restricted, max 1%; 5 safety opinions reviewed (SCCS Opinion). Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in pharmaceutical data.
Tyrosinase inhibitor; chelates copper at the enzyme's active site blocking both monophenolase and diphenolase activity; clinically used at 1–2.5% for melasma and senile pigmentation
Editorial assessment
MODERATE
Preliminary editorial note — not a computed safety verdict.
US NotesNo specific FDA concentration restriction for cosmetic brightening use. Typically used at 1–2.5% in OTC brightening products. Not classified as a drug at cosmetic concentrations. Not GRAS-listed for OTC skin bleaching.
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Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for Kojic Acid.
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Toxicological Studies
10 study endpoints found for Kojic Acid. NOAEL (No Observed Adverse Effect Level) values are used to calculate the Margin of Safety per SCCS methodology.
Endpoint
Value
Route
Species
Study Type
Source
NOAEL
=100 mg/kg
oral
rat
repeated dose toxicity
CIR Safety Assessment
NOAEL
=100 mg/kg
oral
rat
repeated dose toxicity
CIR Safety Assessment
NOAEL
=100 mg/kg
oral
rat
repeated dose toxicity
CIR Safety Assessment
NOAEL
=100 mg/kg
oral
rat
repeated dose toxicity
CIR Safety Assessment
NOAEL
=125 mg/kg
dermal
rat
NOAEL study
CIR Safety Assessment
NOAEL
=125 mg/kg
dermal
rat
NOAEL study
CIR Safety Assessment
NOAEL
=125 mg/kg
dermal
rat
NOAEL study
CIR Safety Assessment
NOAEL
=125 mg/kg
dermal
rat
NOAEL study
CIR Safety Assessment
NOAEL
=150 mg/kg
oral
mouse
repeated dose toxicity
CIR Safety Assessment
NOAEL
=150 mg/kg
oral
mouse
repeated dose toxicity
CIR Safety Assessment
Safety Opinions
Official safety assessments from the Scientific Committee on Consumer Safety (SCCS) and Cosmetic Ingredient Review (CIR).
SCCS OpinionSCCS/1637/2116 March 2022
Verdict: safe
NOAEL: 23.8 mg/kg bw/day (not specified)
Max Concentration: 1% in general
al endocrine disrupting properties of Kojic acid, the SCCS is of the opinion that Kojic acid is safe when used as a skin lightening agent in cosmetic products at concentrations of up to 1%. 2. Alternatively, what is according to the SCCS the maximum concentration considered safe for use of Ko
SCCS OpinionSCCS/1637/2116 March 2022
Verdict: safe
NOAEL: 23.8 mg/kg bw/day (not specified)
Max Concentration: 1% in leave-on
al endocrine disrupting properties of Kojic acid, the SCCS is of the opinion that Kojic acid is safe when used as a skin lightening agent in cosmetic products at concentrations of up to 1%. 2. Alternatively, what is according to the SCCS the maximum concentration considered safe for use of Ko
SCCS OpinionSCCS/1637/2116 March 2022
Verdict: safe
NOAEL: 5.85 mg/kg bw/day (not specified)
Max Concentration: 1% in general
al endocrine disrupting properties of Kojic acid, the SCCS is of the opinion that Kojic acid is safe when used as a skin lightening agent in cosmetic products at concentrations of up to 1%. 2. Alternatively, what is according to the SCCS the maximum concentration considered safe for use of Ko
SCCS OpinionSCCS/1637/2116 March 2022
Verdict: safe
NOAEL: 5.85 mg/kg bw/day (not specified)
Max Concentration: 1% in leave-on
al endocrine disrupting properties of Kojic acid, the SCCS is of the opinion that Kojic acid is safe when used as a skin lightening agent in cosmetic products at concentrations of up to 1%. 2. Alternatively, what is according to the SCCS the maximum concentration considered safe for use of Ko
SCCS OpinionSCCS/1637/2116 March 2022
Verdict: safe
NOAEL: 6 mg/kg bw/day (oral)
Max Concentration: 1% in general
al endocrine disrupting properties of Kojic acid, the SCCS is of the opinion that Kojic acid is safe when used as a skin lightening agent in cosmetic products at concentrations of up to 1%. 2. Alternatively, what is according to the SCCS the maximum concentration considered safe for use of Ko
Pre-Calculated Safety Assessment
Conditional — safe only within SCCS limits:topical skin-lightening cosmetics <=1%; not derivatives; weak skin-barrier caveat
Pre-calculated NOAEL → SED → MoS audit trail for Kojic Acid across SCCS product categories, with measured dermal absorption where available.
SCCS NOAEL Values
NOAEL/LOAEL values cited in official SCCS opinions for Kojic Acid.
Skin absorption and penetration characteristics of Kojic Acid, relevant to systemic exposure and MoS calculations.
Absorption %
10-18%
Penetration Level
epidermis
Penetration Depth
epidermis
Molecular Weight
142.1 Da
Log P
-0.75
Systemic Absorption
minimal
Topical Bioavailability
6-14%
Safety Margin Factor
moderate
Vehicle Dependent
Yes — absorption varies by formulation
Source: J Cosmet Dermatol 2011
IARC Carcinogenicity
International Agency for Research on Cancer (WHO) monograph evaluation.
IARC Group
3
Volume
79
Evaluation Year
2000
Endocrine Disruptor Evidence (Expanded)
Cross-referenced EDC classifications, mechanism data, and dose-response evidence from EDLists, SIN List, and cosmetic-specific detail sources.
Under investigationEvidence: Limited(2022)
Health effects:Yes
Affected pathways:Thyroid
Regulatory framework:Cosmetics
Source list: II (former)
Cosmetic-Specific Mechanism
Category:other
Receptor targets:TR, ERα
LOEC:1 µM (TPO inhibition)
EU status:restricted (max 1%); SCCS 2024 safe at ≤1%; ED review 2019
inhibitor (thyroid peroxidase); weak agonist (ER)
Expanded Jurisdictional Detail
Additional regulatory detail beyond the 7-jurisdiction summary: Saudi SFDA, Korea MFDS, ASEAN ACD, Japan/Korea, Brazil/India, and cross-jurisdictional restriction entries.
JPKR Japan/Korea Cosmetics
Korea (Restricted): max 1.0
Additional Jurisdictional Restrictions (5)
Jurisdiction
Status
Max %
Product Type
CN
banned
-
-
AU
restricted
1.0
skin lightening
GCC
banned
-
Non-compliant skin lightening products
BR
banned
-
-
UK
restricted
-
-
Expanded Dermal Absorption Data
Cross-database dermal penetration: EPA Dryad physics-based, Roberts Mendeley permeation, and SCCS-aggregated measured values.
Aggregated DA Values (2 records across 5 sources)
Type
DA %
Method
Skin Model
SCCS Ref
measured
1.0
method=measured; type=in_vitro
-
-
measured_sccs_opinion
31.0%
-
-
SCCS/1637/21
Typical Use Concentrations
Reported concentration ranges per product category from SCCS/CIR/industry sources.
Product Category
Typical Range
Max Reported
Source
Serum
0.5–2
2
SCCS Opinion
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Antioxidant
Editorial summary
Preliminary editorial summary for Kojic Acid — not a computed safety verdict. See the sourced toxicological data above.
Kojic Acid has a safety rating of "MODERATE" in our database. EU status: restricted. US status: permitted. 10 toxicological study endpoint(s) are available in our database. This ingredient has been reviewed by SCCS Opinion.
Is Kojic Acid allowed in the EU?
Kojic Acid EU regulatory status: restricted. Maximum allowed concentration: 1%. This is based on EU Regulation 1223/2009 and its amendments.
What does Kojic Acid do in cosmetics?
Kojic Acid functions as: Tyrosinase inhibitor; chelates copper at the enzyme's active site blocking both monophenolase and diphenolase activity; clinically used at 1–2.5% for melasma and senile pigmentation. It is classified as a Active Ingredient in our database. CAS number: 501-30-4.
What is the NOAEL for Kojic Acid?
The NOAEL (No Observed Adverse Effect Level) for Kojic Acid is =100 mg/kg based on a repeated dose toxicity study via oral route in rat. A total of 10 study endpoints are available. Source: CIR Safety Assessment.
Is Kojic Acid used outside cosmetics?
Kojic Acid also appears in pharmaceutical data. The cross-vertical cards on this page render same-CAS public rows from the matched databases.
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