Used in cosmetics as a pH balancer. Like all amines, it has the potential for creating nitrosamines. There’s controversy as to whether or not this poses a real problem for skin, given the low concentrations used in cosmetics and the theory that nitrosamines cannot penetrate skin. 
- Fiume M, Heldreth B, Bergfeld W, Belsito D, Hill R, Klaassen C, Liebler D, Marks Jr J, Shank R, Slaga T, et al. Safety assessment of triethanolamine and triethanolamine-containing ingredients as used in cosmetics. Int J Toxicol. 2013;32(S3):59S-83S.