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Tromethamine

TRIS

Well toleratedpH adjusterph-adjusterbufferneutraliser

No meaningful concern for most people; irritation is possible but rare.

Also written as: TRIS · Trometamol · Tris(hydroxymethyl)aminomethane · Triethanolamine substitute

What it is

Tromethamine is a small amine that acts as a gentle alkali and buffer; the same compound is used as a buffering agent in medicines. In cosmetics it neutralises carbomer and other acidic polymers and holds pH steady, and it is frequently chosen instead of triethanolamine because it carries no nitrosamine-formation question.

What it does well

  • Neutralises acidic thickeners and buffers pH gently

    As a weak base it is easier to control than sodium hydroxide and holds pH within a narrow range, which suits gels containing acidic actives.

    Strong evidence

Worth knowing

  • Isolated reports of contact allergy

    Contact allergy to tromethamine has been described occasionally in dermatology practice, mainly with medicated topicals used long-term. It is not a common sensitiser at cosmetic use levels.

    Matters most toPeople with known amine or excipient allergies confirmed by patch testing.

Where the EU stands

No specific restriction

Not restricted for cosmetic use in the EU; it appears in no Annex of the Cosmetics Regulation.

Masks that contain Tromethamine