Toxicological evaluation of 4-methylimidazole: Research advances, health concerns and regulatory perspectives

This review provides a comprehensive analysis of the toxicology, mechanistic pathways, and regulatory evaluations of 4-methylimidazole (4-MI), a nitrogen-containing compound formed during caramel coloring production and industrial synthesis. The study aimed to consolidate evidence on health risks and clarify regulatory inconsistencies. Experimental models show that 4-MI induces hepatotoxicity via oxidative stress, mitochondrial dysfunction, and inflammation, leading to liver cell damage. Neurotoxicity includes behavioral changes, brain mitochondrial injury, and teratogenic effects. Reproductive toxicity has been observed in rodents and zebrafish, impairing sperm function, hormone production, and embryonic development. Although cytotoxic and genotoxic effects-such as DNA damage and chromosomal aberrations-have been reported, standard mutagenicity assays largely remain negative, contributing to regulatory uncertainty. California classifies 4-MI as a possible carcinogen with strict exposure limits, while EFSA finds genotoxic evidence insufficient. Emerging studies also link 4-MI to disruptions in glucose and lipid metabolism, raising concerns about chronic low-dose dietary exposure. Overall, these findings highlight significant public health risks and the urgent need for further toxicodynamic research to inform harmonized regulations and more accurate risk assessments.