CompoundList
Sign in
Cosmetic and personal care ingredients

Hydroquinone vs kojic acid

Hydroquinone (C6H6O2, CAS 123-31-9) and kojic acid (C6H6O4, CAS 501-30-4) are both listed under skin conditioning agents and actives.

Hydroquinone has a molar mass of 110.11 g/mol, kojic acid 142.11 g/mol.

Measured melting points are 170 to 171 for hydroquinone and 153.5 °C for kojic acid.

Hydroquinone carries the GHS signal word Danger, kojic acid Warning.

On CompoundList, 265 suppliers list hydroquinone and 166 suppliers list kojic acid.

Data last updated 7 October 2026

Hydroquinone and kojic acid compared side by side
Hydroquinone chemical structure, C6H6O2, CAS 123-31-9
Hydroquinone
Kojic acid chemical structure, C6H6O4, CAS 501-30-4
Kojic acid
Identity
Name in our databaseHydroquinoneKojic acid
CAS number123-31-9501-30-4
Molecular formulaC6H6O2C6H6O4
Molar mass110.11 g/mol142.11 g/mol
IUPAC namebenzene-1,4-diol5-hydroxy-2-(hydroxymethyl)pyran-4-one
EC number204-617-8207-922-4
Physical properties
AppearanceWhite crystalsPrismatic needles from acetone, ethanol+ether or methanol+ethyl acetate
Melting point170 to 171153.5 °C
Boiling point285 to 287Not recorded
Density1.330 g/cm³ at 20 °CNot recorded
Flash point165 °CNot recorded
SolubilityIn water, 72,000 mg/L at 25 °CSoluble in water, acetone, slightly solluble in ether, insoluble in benzene
LogP (octanol/water)Computed from the structure1.1-0.16
Safety (GHS)
Signal wordDangerWarning
Pictograms
GHS05: Corrosive
GHS07: Harmful or irritant
GHS08: Serious health hazard
GHS09: Hazardous to the environment
GHS08: Serious health hazard
Hazard statements
  • H302 Harmful if swallowed.
  • H317 May cause an allergic skin reaction.
  • H318 Causes serious eye damage.
  • H341 Suspected of causing genetic defects.
  • H351 Suspected of causing cancer.
  • and 1 more
  • H351 Suspected of causing cancer.
UN numberUN 2662Not recorded
Uses and classification
Uses and functions
  • Antioxidants
  • Skin conditioning agents
  • Colorants
  • Fragrance ingredients
  • Escherichia coli metabolite
  • Aetiopathogenetic role
  • Antioxidants
  • Skin conditioning agents
  • Aspergillus metabolite
  • NF-kappaB inhibitor
  • Cosmetic
  • Enzyme inhibitor
CategoryCosmetic ingredients › Skin conditioning agents and activesCosmetic ingredients › Skin conditioning agents and actives
HS code290722Hydroquinone (quinol) and its salts293299Heterocyclic compounds with oxygen hetero-atom(s) only, other
Market on CompoundList
Suppliers265 suppliers166 suppliers
Supplier countries34 countries, most in China, United States, India24 countries, most in China, United States, India
Price rangeOnly prices set by suppliers who manage their own profilePrice on requestPrice on request

Measured and computed values as shown on each chemical page, plus live listings on CompoundList. Details may have changed, please confirm them with the supplier. Safety data is a summary, not an SDS.

Hydroquinone
Kojic acid

More comparisons

Other common chemical pairs, compared the same way.