Melatonin, also known as the 'sleep hormone', is produced by the brain's pineal gland. Melatonin is responsible for regulating sleep and wakefulness. After the sun sets and it starts to get dark, a signal is sent to our brain to start secreting melatonin which causes sleepiness and encourages us over time to drop into a deep sleep. After the sun sets, exposure to artificial blue light 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 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 energized and stimulated at night; thus, it disturbs your 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.
For more detailed information on melatonin, please see our blog article Melatonin 101–Why This Sleep Hormone Supercharges Health and How You Can Produce More