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serotonin
serotonin Serotonin is a chemical signaling substance made from the essential amino acid tryptophan.
Serotonin is a chemical signaling substance made from the essential amino acid tryptophan. In humans it is concentrated in the brain and nervous system, the digestive tract, and platelets, where it helps regulate nerve signaling, gut movement, blood clotting, and cardiovascular function through several receptor types.