A Randomized, Double-blind, Placebo-controlled Research Study Evaluating the Efficacy and Safety of Multi-dose Fecal Microbiota Transplantation (FMT) in Capsule Form as an Intervention to Slow Down the Rate of Biological Aging.

The goal of this clinical trial is to evaluate if multi-dose fecal microbiota transplantation (FMT) capsules can safely and effectively slow down biological aging and reduce chronic low-grade inflammation in adults aged 45 to 80 with metabolic neglect. The main questions it aims to answer are: * Can oral FMT capsules significantly slow the biological pace of aging as measured by the DunedinPACE epigenetic clock(definition)? * Can FMT successfully reduce chronic systemic inflammation (measured by markers such as suPAR, IL-6, and hs-CRP)? Researchers will compare participants receiving the active product to those receiving a matching placebo to see if the microbiome intervention improves metabolic health and cognitive function via the gut-brain axis. Participants will: * Undergo a short-term preparation phase involving targeted antibiotics and standard bowel cleansing. * Receive an 2 initial induction doses of active product (or placebo) followed by 5 regular booster cycles administered approximately every 4 weeks. * Attend periodic clinical visits for physical examinations, blood draws, stool sample collection (at home), and cognitive testing using the CANTAB platform and MoCA scale. * Maintain a participant diary to record adverse events (AE), product administration, stool sample collection, and dietary habits.