Melatonin (aka the sleep hormone) is a powerful hormone and antioxidant that flows through your body's blood stream. It's produced naturally in the pineal gland of your brain when your eyes sense darkness at night.
In addition to helping you sleep better, it regulates your circadian rhythm (your sleep wake cycle). Melatonin is also one of your body's most powerful antioxidants and acts as a free radical scavenger travelling through your body at night as your natural defense against illnesses and cancer driving cells.
Low melatonin levels show links to sleep disorders, obesity, fatigue, anxiety, mood problems, and poor concentration. Recent studies have shown that disrupting your circadian rhythms by exposing ourselves to light at night, particularly blue light, can raise the risk of heart attack or stroke by 40 percent. Studies have also shown links between low melatonin levels and breast cancer in women and increased risk of prostate cancer in men.
Artificial lights from gadgets at night (laptops, tv, smartphones etc.) emit a blue glow, a light wavelength similar to the day time sky. This blue light enters your eyes and signals your brain to think it is still day time. Taking this signal, your brain then restricts the flow of melatonin through your body.