PCA of the 1 H-NMR metabolite profiles, which compared silymarin with controls using the area under the curve (AUC) values, did not reveal clear clustering. This lack of distinct grouping was primarily due to considerable variation among individual donors. The individual metabolomic profile is significantly more pronounced than the effect of silymarin treatment (Fig. ). Considering these findings, a pairwise statistical analysis was conducted for the overall donor population regardless of age (n = 20), which identified 14 metabolites that significantly differed with the addition of silymarin. The introduction of silymarin was linked to a notable decrease in the production of SCFAs such as acetate, butyrate, and propionate, as well as branched-chain fatty acids (BCFAs) including isobutyrate and isovalerate. Additionally, a reduction was observed in certain carboxylic acids, specifically valeric acid and phenylacetic acid, as indicated by changes in the AUC. Furthermore, silymarin addition resulted in lower utilization of glucose, trehalose and certain branched-chain amino acids (BCAAs, i.e. valine, leucin, isoleucin), as evidenced by the higher AUC for these metabolites. Figure illustrates the time course of the six most significantly different metabolites, with statistical differences for each time point. When this analysis was performed separately for each age group (n = 10), the effect of silymarin was similar in both groups to that observed in the overall donor population. However, the effect was more pronounced in healthy elder donors. In older subjects, nine metabolites showed differences with the addition of silymarin, whereas only seven metabolites were affected in younger donors. Additionally, the relative fold changes were higher in the older group compared to the younger group. Table shows the effects of silymarin on metabolite changes in both age groups and the overall donor population, along with the respective fold changes.