Is serotonin a hourmone

Serotonin is primarily a neurotransmitter, not a hormone, although it can act like one in certain contexts. It is produced in the brain and the intestines and plays a key role in regulating mood, appetite, and sleep. While it influences various bodily functions similar to hormones, it does not fit the strict definition of a hormone, which typically refers to signaling molecules released into the bloodstream to affect distant organs.