Some groups or communities believe that ‘We literally have a third eye, which connects us to spiritual dimensions and supernatural forces’ and it is claimed that the Pineal Gland (PG) is that third eye. Majority believes that PG is one of the endocrine glands in vertebrates and secretes mainly a hormone melatonin which regulates circadian rhythm or sleep cycle. In some lower vertebrates, PG has a well-developed eye like structure and in others if not organized as an eye, it functions like a light receptor. Neurobiological effects of meditation and mindfulness have been detected in the form of increased molecular levels of melatonin and dopamine. It is said that PG is relevant in medicine and healthcare for behavior change,  stress regulation and treatment of addictions.  Its deep location in brain suggested the philosophers throughout history that it possesses a particular importance. On the top of all, PG is also thought to secrete dimethyl tryptamine (DMT), a naturally occurring psychedelic compound called ‘The Spirit Molecule’ during dreaming, spiritual and mystical experiences and at the time of death. The role of  PG as an endocrine gland and its secretory activity is poorly understood. Pineal gland’s full purpose is still a bit of mystery and yet to be known but researchers suggest that we are getting closer to understanding PG and more about the entire endocrine system.

Keywords: Neurobiological Effects; Melatonin; Circadian Rhythm; Pineal;  Psychedelic.