Workflow to create the metabolite master list (MML). The first 2 boxes describe the importing of metabolites from the HMDB (Human Metabolome Database; Wishart et al., 2007) and MetaboLights data repository (Haug et al., 2013). The third to fifth boxes represent the filters that were used to refine the metabolite list based on HMDB ontology, and in the sixth box further filters based on chemical ontology were applied. This process yielded the MML of detectable human-relevant metabolites.