This is the fist of a series of short videos on the main ‘Feel Good’ brain molecules such as Serotonin, Dopamine, Oxytocin and Melatonin. Serotonin is a neurotransmitter which plays an important role in regulating mood, memory, learning, and blood pressure, as well as appetite and body temperature. Serotonin is synthesized from tryptophan (an essential amino acid) and it is primarily found in the gastrointestinal tract (90%), where it regulates bowel movement and in the central nervous system (CNS where it performs its primary functions. A natural source of tryptophan as a dietary supplement is the Griffonia simplicifolia plant (sold over the counter as 5HTP). A seed extract of this plant taken daily naturally increases serotonin levels. The herbal extract of St.John's wort (Hypericum perforatum) which is often used in the treatment of mild to moderate depression and anxiety disorders seem to be effective due to several chemicals, including hypericin, hyperforin, and flavonoids which stimulate the production of the serotonin and dopamine. Serotonin is regarded as an adaptogen, since it promotes contentment and it is a responsible for the regulation of mood, appetite and normal sleep. It also has some cognitive functions, including memory and learning.