TRIETHYL CITRATE
Triethyl citrate, also known as citric acid ester, is a solvent and diluent and is not considered to be a skin sensitizer. It is even approved for use in food products.(1)
A study also investigated the efficacy of a formulation containing triethyl citrate and ethyl linoleate on acne vulgaris. Triethyl citrate is hydrolyzed by C. acnes (which triggers acne under certain circumstances) into the diethyl ester and monoethyl ester of citric acid, as well as citric acid itself. As a result, the microenvironment of the pores becomes acidic, leading to reduced growth of C. acnes, inhibition of bacterial lipases, and modulation of the keratolytic effect.(2)
(1) Fiume, M. M., Heldreth, B. A., Bergfeld, W. F., Belsito, D. V., Hill, R. A., Klaassen, C. D., ... & Andersen, F. A. (2014). Safety assessment of citric acid, inorganic citrate salts, and alkyl citrate esters as used in cosmetics. International Journal of Toxicology, 33(2_suppl), 16S–46S.
(2) Charakida, A., Charakida, M., & Chu, A. C. (2007). Double-blind, randomized, placebo-controlled study of a lotion containing triethyl citrate and ethyl linoleate in the treatment of acne vulgaris. The British Journal of Dermatology, 157(3), 569–574. https://doi.org/10.1111/j.1365-2133.2007.08083.x
