Serotonin (also known as 5-hydroxytryptamine, or 5-HT) is one of the most talked-about neurotransmitters– molecules that help your nervous system communicate. You may know it as “the happy molecule” because of its role in regulating happiness, anxiety, and mood. The best-known indicators of low serotonin include depression and anxiety, but it plays a larger role in the body as well. …