Desmethylcitalopram hydrochloride is the primary metabolite of citalopram, an SSRI antidepressant. It exhibits weaker selective serotonin reuptake inhibition compared to the parent drug and is not used as a therapeutic agent. Primarily employed in pharmacological research to study antidepressant effects and drug metabolism. Serves as a reference standard in bioanalytical methods, such as measuring plasma concentrations via HPLC or LC-MS/MS, and in pharmacokinetic studies. Also utilized in the development and quality control of analytical assays for citalopram and its metabolites in generic formulations.