Even though the use of a public (metabolomics) repository using standardized formats for data annotation should make manual identifier mapping unnecessary, the reality turned out to be different. For example, the metabolites found to be related to age in MTBLS440 were described in a Table in the accompanying paper; however, the Table was constructed as a Figure and HMDB identifiers were used in the paper, whereas the metabolites in the repository were annotated with ChEBI identifiers. Furthermore, the names of the compounds mentioned in the paper did not always match with the ones in the repository (since the protonation calculations on the chemical structures in ChEBI and HMDB differ, leading to different mappings from ChEBI to HMDB and vice versa). For the third dataset (Rist et al. only the top 25 changed metabolites were given, other metabolites contributing to the model to a lesser degree could not be obtained, without redoing the original analysis. Finding and reanalyzing (public) metabolomics data is a time-consuming task due to the issues mentioned above.