Top 10 food to boost serotoninbr br Serotonin is a key neurotransmitter that contributes to the regulation of mood, emotion, and well-being. Often called the "happiness hormone," it helps maintain a positive mood, feelings of contentment, and emotional stability. Serotonin also plays a role in regulating sleep, appetite, and digestion. Imbalances in serotonin levels are associated with conditions such as depression and anxiety. Activities like regular exercise, a healthy diet, and exposure to sunlight can help increase serotonin levels naturally.