Zest is a compact two-in-one device, which works as a SAD light and wake-up light. Blue-enriched white LEDs gradually brighten to wake you in the morning; five light levels provide bright light therapy to lift mood, boost concentration, restore natural energy and treat the symptoms of SAD. Zest can be used as a wake-up light for a natural start to the day. Waking up with a gradual sunrise is a signal for your body to ease production of sleep hormones (e.g. melatonin) and increase those that help you get up and go (e.g. cortisol). Wake-up lights help to keep your sleep cycle on track, boosting mood, energy and productivity levels all day. In addition, you can use Zest for bright light therapy in the winter months or when you're stuck indoors. Extra bright light is proven to put you in a better mood and make you feel more awake and using Zest everyday will make a big difference to symptoms of SAD such as tiredness, overeating and a lack of energy and motivation.