serotonin
n. uncountablen. a chemical in your brain and body that helps control your mood, sleep, and digestion. It is often called the 'feel-good' chemical because it helps you feel calm and happy.
n. a neurotransmitter derived from tryptophan that is involved in the regulation of mood, appetite, sleep, and cognitive functions. Primarily found in the gastrointestinal tract, blood platelets, and the central nervous system.
Exercise can help increase the levels of serotonin in your brain.
Many modern antidepressants work by increasing the amount of serotonin available in the brain to help stabilize a patient's mood.
While primarily recognized for its role in emotional regulation, the vast majority of the body's serotonin is actually produced in the gut, where it facilitates various digestive processes.
From sero- + tone + -in.
Usually uncountable when referring to the chemical substance; can be countable in medical contexts referring to specific types or levels.