13 Gut-Brain Axis Secrets: How Your Digestion Impacts Your Mood

Secret #3: Serotonin's Surprising Gut Origin: The Mood Molecule's Manufacturing Hub

When you think of serotonin, the "happiness hormone," you likely think of your brain. The startling secret? A staggering 90-95% of your body's serotonin is actually produced and stored in your gut. This vast gut-derived serotonin largely impacts gastrointestinal motility and local immune responses, but its influence on brain function via the gut-brain axis is profound. Imbalances in gut serotonin production or signaling can disrupt mood, sleep, and appetite, underscoring how directly your digestive system acts as a major manufacturing hub for a key mood-regulating molecule.