Melatonin, also known as the 'sleep hormone', is produced by the brain's pineal gland. Melatonin is responsible for regulating our periods of both sleep and wakefulness.
After the sun sets and it becomes dark, a signal is sent to our brain to start secreting melatonin to cause sleepiness, encouraging us over time to curl up and drop into a deep and restful sleep. Exposure to artificial blue light after the sun sets disrupts this evolutionary process of 'priming' you for sleep. This harmful light suppresses the release of melatonin as it signals your brain that it is still daylight, trying to keep you awake and alert.
Melatonin plays a significant role in our overall health, one of its key roles is to counteract stimulating and energetic hormones such as cortisol in your system. When melatonin is high, cortisol will be low, this allows us to be in a low stress and relaxed state which promotes our body to obtain restful sleep and boosts cell regeneration. However if melatonin is low (due to being suppressed from blue light), cortisol will remain high - keeping you energised and stimulated at night, disturbing quality of sleep. Constant high cortisol equates to constant high stress, which will wreak havoc on the body! In this way, melatonin is necessary to maintain a regular and healthy body clock and sleep wake cycles.

