There are plenty of light therapy devices around. But most of these work on the obvious light sensors, our eyes. The HumanCharger, uniquely, uses the ears. It takes the form of a pair of earphones with LEDs that nest in your ear canals and beam light into the recesses of the skull.
The claimed benefits of 12 minutes a day spent wearing the earphones are increased energy and mental alertness, improved mood and, if you’ve been on a long-haul flight, decreased jetlag.
Devices made to make you feel better are hard to assess. My experience with the iPod Shuffle-like HumanCharger was pleasant if unremarkable. I did feel in good shape having tried it, but there could have been many reasons for that and we know correlation doesn’t imply causation. But using it is easy, and the research on the website is interesting, if not conclusive. The company offers a refund if you don’t feel it works within 30 days.