Maleic Acid

AKA: 110-16-7, Cis-butenedioic acid, Toxilic acid, (2Z)-but-2-enedioic acid, Maleinic acid, Malenic acid, (Z)-Butenedioic acid, Cis-1, 2-Ethylenedicarboxylic acid
Synthetic
Acid
Not Clean
OriginProduced from maleic anhydride, a synthetic organic compound derived from petroleum-based hydrocarbons or benzene. Synthesized through hydration of maleic anhydride, converting it into maleic acid through chemical reaction with water.
Maleic acid is an industrial raw material for the production of glyoxylic acid by ozonolysis. Maleic acid is an organic compound which is a dicarboxylic acid (molecule with two carboxyl groups). The molecule consists of an ethylene group flanked by two carboxylic acid groups. Maleic acid is the cis isomer of butenedioic acid, whereas fumaric acid is the trans isomer. The cis isomer is the less stable one of the two; the difference in heat of combustion is 22.7 kJ/mol. The physical properties of maleic acid are very different from that of fumaric acid. Maleic acid is soluble in water whereas fumaric acid is not and the melting point of maleic acid (130 - 131 degree centigrade) is also much lower than that of fumaric acid (287 degree centigrade). Both properties of maleic acid can be explained on account of the intramolecular hydrogen bonding that takes place at the expense of intermolecular interactions. Maleic acid is converted into maleic anhydride by dehydration, to malic acid by hyd
Solubility greater than or equal to 100 mg/mL at 66 °F (NTP, 1992)
Formula
C4H4O4
Mol. Weight
116.07
CAS #
110-16-7
Form
Liquid
State
Maleic acid is a colorless crystalline solid having a faint odor. It is combustible though it may take some effort to ignite. It is soluble in water. It is used to make other chemicals and for dyeing
Skin Types
●all-skin-types
Best For
Uneven Texture
Pregnancy & Breastfeeding Safe
Caution
Functions
Buffering
Stabilizes pH
Brightens Skin
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️Safety-assessed1 review →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
EWG
4
CIR
Safe as used
Pregnancy
Caution
CIR Safety Findings
Eye Irritant in Testing
1 study / 1 irritating (CIR 419)
Skin Irritant in Testing
2 studies / 2 irritating / reactions minimal (CIR 419)
Sensitizer in Testing
1 study / 1 sensitizing (CIR 419)
Regulatory Status
USA✔ permitted
EU⚠ restricted
JAPAN⚠ restricted
CANADA⚠ restricted
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR