For all three studies above, the metabolites to be queried were harmonized to one database (Wikidata). This action aids in finding compounds without mappings to ChEBI or HMDB and overcomes issues with different types of stereochemistry (D-, L-, and DL-forms). The strategy to find identifiers for the age-related metabolites consisted of the following steps. First, link the existing ChEBI identifiers from the two studies in Metabolights to the accompanying Wikidata identifiers, by comparing the name, ChEBI identifier, and isomeric SMILES from the dataset of the study and the relevant metabolites mentioned in the papers published from these studies, to the information in Wikidata. Second, for the MTBLS404 study, the accompanying HMDB identifier was noted and compared to the data present in the Table of the original paper showing the age-related metabolites (annotated with HMDB). For the compounds where there was no match found, the reverse order of steps was undertaken, meaning finding the corresponding Wikidata identifier for the given HMDB identifier and comparing the names. From there, the accompanying ChEBI identifier was noted and compared to the data present in the study file. For the study from Rist et al., the agerelated identifiers were given in a Figure and supplementary file), however, only the names of the compounds were provided (not the data used to construct the Figures). In order to derive the sex and fluid-independent age-related compounds, these compound names were compared to the (trivial) names within Wikidata, and the accompanying Wikidata identifier was retrieved. We manually read out the weight values for the SVM and glmnet data from Figure (titled "Metabolite patterns for the prediction of age in men)" of the original paper; these values differ from the values provided for women in the supplementary materials (Figure titled "Metabolite patterns for the prediction of age in women"); no Figure was available for the sex independent data.