Tromethamine
Also known as Tris, Trometamol, THAM, 2-Amino-2-(hydroxymethyl)propane-1,3-diol
“CIR Expert Panel says: safe as used in cosmetics.”
Tromethamine (2-amino-2-(hydroxymethyl)propane-1,3-diol; CAS 77-86-1) is an organic amine used as a pH buffer and neutralizer in cosmetic formulations, often as an alternative to triethanolamine. The CIR Expert Panel assessed tromethamine together with aminomethyl propanediol and aminoethyl propanediol in their final report (09/2013) and confirmed safety in cosmetic use (QRT Finding: S). The 2018 CIR publication (Becker et al., Int J Toxicol 37(1_suppl):5S-18S, PMID 29761730) documents the panel's evaluation of animal and human safety data and concludes tromethamine is safe in cosmetics at practiced use concentrations. Unlike triethanolamine, tromethamine does not form N-nitroso compounds, which is a key safety advantage as a TEA substitute.
pH buffer and neutralizer for cosmetic formulations; commonly used as a safer alternative to triethanolamine (TEA) because it does not form N-nitroso compounds
CIR Expert Panel concluded safe as used in cosmetics (Final report 09/2013; confirmed in Becker et al., IJT 2018, PMID 29761730)
Good buffering capacity in the physiologically relevant pH range (~7–9); effective neutralizer for carbomer and other polymeric thickeners
- · Eye irritation potential at high concentrations — typical cosmetic use as pH adjuster at low concentrations is considered safe
- · Alkaline pH (pKa ~8.1); formulations should be pH-adjusted to avoid irritation
CIR Quick Reference Table (12/2017, revised 07/2018) — Tromethamine row: Finding=S, Citation=Final report 09/2013 available from CIR
“Tromethamine | S | | Final report 09/2013 available from CIR”— QRT-122017revised072018.pdf, p. 137