1-Methyl-L-histidine is an endogenous metabolite of some animal species, excluding humans. 1-Methyl-L-histidine is an L-histidine derivative substituted by a methyl group at postion 1 on the imidazole ring (N(tele)). 1-Methylhistidine is a breakdown product of animal protein that can be used as a urinary marker for meat consumption and to distinguish 3-methyl-L-histidine from endogenous vs. dietary sources.