The Valkee Human Charger: can 30 blind mice really be wrong?

Human Charger sounds like a doofus American sports position, but this week’s product is even harder to understand. I am holding a small battery-powered device from Finland that exactly resembles an iPod Shuffle (remember them?), down to the wired buds to wear in my ears. It doesn’t play music; instead, the buds emit very bright LED light. Billing itself as “sunlight on demand”, the Human Charger works on the notion that light pumped into the brain “keeps winter blues at bay, increases mental alertness, reduces jet lag symptoms and gives you energy whenever you need it”. It’s literally a bright idea. I plug in, and wait to see the light. Or rather, not.

The makers are sensitive to scepticism. Their website has a page of dull-looking scientific corroboration, topped by a bald statement in 250-point type: “Main takeaway: the human brain is inherently sensitive to light.”

Research at the University of Oulu in Finland indicates that parts of the brain are themselves photosensitive, similar to the eyes. Light sent through ear canals, dispersed in the cerebrospinal fluid that our brains float in, reaches the temporal lobe and, I don’t know, projects the lyrics to Shiny Happy People by REM there.

The experiments sound wild: some conducted on 30 blind mice, an upgrade on the nursery rhyme. One involved shining a light into a cadaver with its brain removed. Another found improved response time in ear-lit pro-hockey players. Yet another reported spectacular mood improvements among subjects, as defined by the Beck Depression Inventory. (He plays all his own lab instruments, you know.)

It is certainly sleek. Aluminium body, one-button functionality. Very bright, UV-free LEDs. At the end of my week of testing on a single charge, the device was still good to go. As for recharging myself, that required 12 minutes of in-ear light a day, counted down by an illuminated progress ring on the front.

I can see why light-deprived Finns would go wild for this. Powerfully marketed and previously known as Valkee, after the company behind it, the device has sold more than 90,000 units. I admire the look of the backlit earphones, and the idea of sunshine in your pocket is a sweet hook. I’m thrilled by the concept of side-lighting my brain, opening the mental curtains, blasting away the darkness. But is the pioneering theory behind this an oracular miracle or auricular hogwash?

Using my extra alertness, I look more closely at the website citations. The research isn’t peer-reviewed in the way most would define the term. All but one of the studies are published by a small, overlapping group of names from Oulu University, some of whom are on the board of Valkee. The company’s search results make me wince. In 2012, the Finnish investigative TV programme MOT looked into Valkee, revealing unfounded claims and huge problems with its research. The show claimed the research wasn’t even able to demonstrate any efficacy over placebo – the company disputes this. In 2013, an independent test was performed by scientists in Basel, Switzerland, and found that “extraocular light via the ear canal does not acutely affect human circadian physiology, alertness and psychomotor vigilance performance”. So the science is probably grade-A chutney, but this is 2020 and where we’re going, we don’t need roads.

How did this thing actually make me feel? I plugged the buds into my lugs for a week following a long-haul flight, to see if I found the jet lag claims to be true. At 4am on several subsequent days, I was able to confirm I did not. How about my anxiety or low mood? Unaffected. The only change I noticed was an irritable bowel, which I don’t blame the Human Charger for. Although if they want to publish it as anecdotal testimony, they can. The product looks great, but aesthetics don’t count for anything on their own. In fact they could rename the product Anaesthetic, because I felt nothing at all. You could buy an iPod and break it for less.