Melatonin is the only known hormone synthesised by the pineal gland and is released in response to darkness hence the name, “hormone of darkness” [10]. Melatonin provides a circadian and seasonal signal to the organisms in vertebrates.
The precursor to melatonin is serotonin, a neurotransmitter that itself is derived from the amino acid tryptophan. Within the pineal gland, serotonin is acetylated and then methylated to yield melatonin. Synthesis and secretion of melatonin is dramatically affected by light exposure to the eyes.
Your levels of melatonin are boosted when it's dark, whereas serotonin levels increase in sunshine and light environments. In short, melatonin helps you get to sleep and serotonin helps you feel awake when you get up the next day.10 Apr 2017,
The third eye is often associated with religious visions, clairvoyance, the ability to observe chakras and auras, precognition, and out-of-body experiences. ... Taoism teaches that the third eye, also called the mind's eye, is situated between the two physical eyes, and expands up to the middle of the forehead when opened.