Methacrylic Acid
molecular structure · PubChem
AKA: 79-41-4, 2-methylprop-2-enoic acid, 2-Methylacrylic acid, Methylacrylic acid, 2-Propenoic acid, 2-Methylpropenoic acid, 2-Methyl-2-propenoic acid, Alpha-Methylacrylic acid, 2-Methylenepropionic acid
Synthetic
Occlusive
Acid
Not Clean
Methacrylic acid, stabilized appears as a clear colorless liquid with a pungent odor. Corrosive to metals and tissue. Combustible. Flash point 170 °F. Melting point 61 °F. May polymerize if contaminated or heated. If polymerization takes place inside a closed container, the container may violently rupture. Less dense than water and is soluble in water. Vapors heavier than air. Used to make plastics.
Solubility greater than or equal to 100 mg/mL at 63 °F (NTP, 1992)
Formula
C4H6O2
Mol. Weight
86.09
CAS #
79-41-4
Form
Liquid
State
Methacrylic acid appears as a clear colorless liquid (or low-melting solid) with a pungent odor. Corrosive to metals and tissue. Flash point 170 °F. Melting point 61 °F. May polymerize exothermically
Functions
Film Forming
Creates a physical seal on skin to lock moisture in and keep irritants out. The "slugging" ingredient — barrier protection.
Creates Protective Barrier
Wound Healing
Fights Bacteria
Traditional Use
Developed in the early 20th century as part of modern polymer chemistry; used in cosmetics since mid-century as a raw material for creating film-forming and thickening agents in skincare and haircare products.
Skin Types
●all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Caution
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory1 listing →
🛡️Safety-assessed2 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR