However, only 3‐HAA and 5‐HT exhibited consistent changes between donor and recipient mice (Figure 3E–G; Figure S3G, Supporting Information), which aligns with prior findings that KYNU and KMO in the KP pathway may be microbially encoded.[33] Similarly, we further confirmed that serum 3‐HAA levels were decreased in PCOS patients and P‐FMT mice compared with healthy individuals and H‐FMT mice, respectively (Figure 3H). This evidence concerns the gene NPPA and polycystic ovary syndrome.