1-Methyladenosine-d3 hydrochloride is the hydrochloride salt form of deuterium-labeled 1-Methyladenosine. This compound is a modification of RNA that serves as a biomarker for tumors, with elevated levels in the body linked to cancer development. Upon methylation, 1-Methyladenosine upregulates the expression of PPARδ, regulates cholesterol metabolism, and activates the Hedgehog signaling pathway, thereby driving the onset of liver tumors.