<ul data-eligibleForWebStory="false">Synthetic molecular communication (SMC) enables continuous monitoring of biochemical signals in future healthcare systems.Closing the loop between sensing and actuation in SMC requires detection and generation of in-body molecular communication signals.This paper focuses on using the gut-brain axis (GBA) for therapeutic modulation to indirectly generate signals inside the human body.The proposed approach leverages personal health data and machine learning to design more effective GBA modulation-based treatments.