By Aditya Shukla, psychologist
It's a neurotransmitter and a hormone. Hormone: It is made by the gastrointestinal tract and supplied via blood to other parts of the body. Neurotransmitter: It is released by the neuron's synapses to communicate with other brain cells.
Its primary psychological function is to improve mood and positive feelings. That's why it's called the "feel good" molecule. It's non-psychological role is regulating the intestine and blood clotting.