I started using Valkee already in 2011 for my winter blues. I tried traditional bright light lamps before, but was not able to find time to use them (required 60 minutes sitting still close to the lamp) and did not feel that they help. My biggest symptoms were difficulty to wake up in the mornings and cravings for sweets. Valkee took these out completely. If I cease using Valkee during the winter time, the symptoms come back in one week. I use Valkee from October to January.