HEMA

What Is It?

Methacylate ester monomers (Butyl Methacrylate, t-Butyl Methacrylate, Cyclohexyl Methacrylate, Di-HEMA Trimethylhexyl Dicarbamate, Ethoxyethyl Methacrylate, Glycol HEMA-Methacrylate, HEMA, HEMA Acetoacetate, Hydroxypropyl Methacrylate, Isobornyl Methacrylate, Isobutyl Methacrylate, Isopropylidenediphenyl Bisoxyhydroxypropyl Methacrylate, Lauryl Methacrylate, Methoxydiglycol Methacrylate, PEG-4 Dimethacrylate, Triethyleneglycol Dimethacrylate, Trimethylolpropane Trimethacrylate) are colorless liquids. Methacrylate ester monomers are used in nail enhancement products.

Why is it used in cosmetics and personal care products?

Methacrylate ester monomers are used in nail enhancement products to build or lengthen the nail.

Scientific Facts:

Methylacrylate ester monomers are relatively small chemical compounds. They are produced by reacting methacrylic acid with the appropriate alcohol. For example, Butyl Methacrylate is prepared from the reaction of methacrylic acid and butyl alcohol. Many of the methacrylate ester monomers are used in dentistry as resins, adhesives and restorative materials.

Safety Information:

The Food and Drug Administration (FDA) includes Butyl Methacrylate on its list of indirect food additives. It may be used as a component of coatings, and polymers in food contact surfaces. The safety of Methacrylate ester monomers has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated the scientific data and concluded that Butyl Methacrylate, t-Butyl Methacrylate, Cyclohexyl Methacrylate, Di-HEMA Trimethylhexyl Dicarbamate, Ethoxyethyl Methacrylate, Glycol HEMA-Methacrylate, HEMA, HEMA Acetoacetate, Hydroxypropyl Methacrylate, Isobornyl Methacrylate, Isobutyl Methacrylate, Isopropylidenediphenyl Bisoxyhydroxypropyl Methacrylate, Lauryl Methacrylate, Methoxydiglycol Methacrylate, PEG-4 Dimethacrylate, Triethyleneglycol Dimethacrylate and Trimethylolpropane Trimethacrylate were safe as used in nail enhancement products when labeled to avoid skin contact.

More safety Information:

CIR Safety Review: While Ethyl Methacrylate is the primary monomer used in nail enhancement products, other methacrylate esters are also used. The polymerization rates of these methacrylate esters are within the same range as Ethyl Methacrylate. While data were not available on all of these methacrylate esters, the available data demonstrated little acute oral, dermal, or intraperitoneal toxicity.In a 28-day inhalation study, Butyl Methacrylate caused upper airway irritation; the No Observed Adverse Effect Level (NOAEL) was 1801 mg/m3. In a 28-day oral toxicity study, t-Butyl Methacrylate had a NOAEL of 20 mg/kg body weight/day. Dosages of 0.2 to 2.0 g/kg/day of C12 to C18 methacrylate monomers for 13 weeks exhibited effects only in the highest dose group: weight loss, emesis, diarrhea, mucoid feces, or salivation were observed. Butyl Methacrylate and Isobutyl Methacrylate were mildly irritating to the eyes. HEMA was corrosive when instilled in the eye, while PEG-4 Dimethacrylate and Trimethylolpropane Trimethacrylate were minimally irritating to the eye.Dermal irritation caused by methacrylates has been documented. HEMA, Isopropylidenediphenyl Bishydroxypropyl Methacrylate, Lauryl Methacrylate and Trimethylolpropane Trimethacrylate were strong sensitizers; Butyl Methacrylate and Cyclohexyl Methacrylate were moderate sensitizers; Hydroxypropyl Methacrylate was a weak sensitizer; and PEG-4 Dimethacrylate and Triethylene Glycol Dimethacrylate were not sensitizers. Ethylene Glycol Dimethacrylate was not a sensitizer in one study, but was a strong sensitizer in another.There was cross-reactivity between various methacrylate esters in some sensitization tests. Inhaled Butyl Methacrylate, HEMA, Hydroxypropyl Methacrylate, and Trimethylolpropane Trimethacrylate were developmental toxicants at high exposure levels (1000 mg/kg/day). None of the methacrylate ester monomers that were tested were shown to have any endocrine disrupting activity. These methacrylate esters were mostly non-mutagenic in bacterial test systems, but weak mutagenic responses were seen in other test systems. Chronic dermal exposure to PEG-4 Dimethacrylate or Trimethylolpropane Trimethacrylate did not result in increased incidence of skin or visceral tumors. The carcinogenicity of Triethylene Glycol Dimethacrylate (5, 25, or 50%) was assessed in a skin painting study. It was not carcinogenic at any dose level tested.Ethylene Glycol Dimethacrylate, HEMA, Isopropylidenediphenyl Bishydroxypropyl Methacrylate, Triethylene Glycol Dimethacrylate, and Di-HEMA Trimethylhexyl Dicarbamate were considered to be capable of causing hypersensitivity/allergy in humans. The CIR Expert Panel was concerned about the strong sensitization and cross- or co-reactivity potential of the methacrylate esters reviewed in this report.However, data demonstrated the rates of polymerization of these Methacrylates were similar to that of Ethyl Methacrylate and there would be little monomer available for exposure to the skin. In consideration of the toxicity data, the CIR Expert Panel concluded that the use of these methacrylate esters should be restricted to nail enhancement products which would limit skin contact.Link to FDA Code of Federal Regulations for Butyl Methacrylate

Methacrylate ester monomers may be used in cosmetics and personal care products marketed in the European Union according to the general provisions of the Cosmetics Regulation of the European Union. 

More Scientific Information:

Methacrylate ester monomers, in comparison to ethyl methacrylate, are secondary monomers used to speed up polymerization and act as cross-linkers. In cosmetics and personal care products, Methacrylate ester monomers function as artificial nail builders. They form a hard material on the nail that is then shaped.