---! Is pistachio rich in melatonin !--- Is pistachio rich in melatonin : Melatonin is a hormone produced in the pineal gland, a small gland in the brain, that helps regulate the cycle of sleep and wakefulness in the body. There is very little melatonin in foods such as meats, beans, fruits, and vegetables. Melatonin is also marketed as a dietary supplement, although it is not a well-known nutritional value. Irregular...