pH Adjuster
METHYLETHANOLAMINE
Safety score · 0–100
Caution
Derived from EU CosIng regulatory status, PubChem hazard data and published research. How we score.
A secondary amine pH adjuster — problematic because it can form carcinogenic nitrosamines when combined with nitrosating agents.
Methylethanolamine (CAS 109-83-1, N-methylethanolamine, MMEA) is a secondary alkanolamine used industrially as a pH adjuster and chemical intermediate. Its cosmetic use is highly restricted because secondary amines can react with nitrites and other nitrosating species to form N-nitroso compounds (such as N-nitroso-N-methylethanolamine), many of which are IARC Group 2A/2B carcinogens. EU and COLIPA guidelines restrict the free amine in finished cosmetics and require control of nitrosating impurities. As the free base it is a skin, eye, and respiratory irritant (GHS category signal word Danger). In neutralized form it exists as the conjugate salt of fatty acids or other acids, but nitrosamine precursor status remains a concern.
Skin benefits
- Limited — primarily a formulation aid
Known concerns
- Nitrosamine precursor — forms Group 2A/2B carcinogens
- GHS-labeled skin/eye/respiratory irritant as free base
- EU restrictions on free amine
- Not suitable for leave-on cosmetic use
References
EU CosIng database
European Commission cosmetic ingredient registry: regulatory status, restrictions, authorised functions.
Related ph adjusters
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This profile is for educational purposes and does not constitute medical advice. Regulatory status and scientific understanding evolve, so always read the physical product label and consult a healthcare professional for personal concerns.