Sleep supplements promote a healthy sleep cycle, restful and restorative sleep, and support nervous system health. Getting a good night’s rest is vital for good health. Research has found that lack of quality sleep has immediate negative effects on hormones, exercise performance, and brain function. The sleep cycle is made up of four stages and the most restorative sleep appears to take place during deep sleep and REM sleep. Restorative sleep helps you wake up feeling well rested and refreshed. Melatonin is a hormone that plays an important role in sleep and is released in the brain once it starts getting dark. Some things that can affect sleep are sleep disorders, pain, mood disorders, and lifestyle habits.