Serotonin is a neurotransmitter that is widely regarded as a key player in regulating mood, anxiety, and happiness. Chemically derived from tryptophan, serotonin impacts various parts of the body, influencing the functioning of the cardiovascular, renal, immune, and gastrointestinal systems. In the brain, it is primarily associated with feelings of well-being and happiness and is often a target for antidepressant medications like SSRIs (selective serotonin reuptake inhibitors), which help increase serotonin levels in the nervous system. Beyond its role in mood regulation, serotonin also affects sleep patterns, appetite, temperature regulation, and pain perception.