Sero Who? What the heck is serotonin, what are serotonin levels and why should you care? Serotonin is a neurotransmitter, a chemical messenger, found primarily in the central nervous system, blood, and gastrointestinal tract. It affects many brain and bodily functions, among them, mood. Serotonin stabilizes and regulates mood by curbing anxiety, helping you feel focused [...]