6-Methylniacin, or 6-methylpyridine-3-carboxylic acid, is a substituted derivative of nicotinic acid (vitamin B3). The methyl group at the 6-position alters its physicochemical properties compared to niacin while retaining the carboxylic acid functionality on the pyridine ring. It is found in trace amounts in certain plant-based foods and has been investigated in metabolic studies for its potential role in NAD+ precursor pathways. The compound exhibits moderate water solubility and is used in research on niacin analogs for lipid metabolism and cardiovascular health applications. Its structure consists of a pyridine ring with a carboxylic acid at position 3 and a methyl substituent at position 6.