It is a mood-boosting effect hormone or also known as nature’s feel-good chemical. It is associated with learning and memory, regulating sleep, digestion, regulates mood, some muscular functions etc. Due to the imbalance of serotonin in the body, brain does not produce enough of the hormone to regulate mood or stress level. Low level of serotonin causes depression, migraine, weight gain, insomnia, craving of carbohydrate etc. Excess level of serotonin in the body causes agitation, stage of confusion, sedation etc.