No, Light-Emitting Headphones Will Not Cure Seasonal Depression.
If you tend to feel sad during the darker months of the year , it’s well known that a little sunshine can help. If you don’t get enough sunlight, a light therapy unit (which shines in your direction while you eat breakfast) may be your best bet. But there’s also a gadget that some people swear by: headphones that act like tiny flashlights, shining light into the ear canals. Are they legal?
Skincare TikToker @emmahoareau1 posted a sneak peek of her LED headphones for people who “suffer from Seasonal Affective Disorder like me,” concluding that they are “absolutely life-changing.” The subsequent video went viral, and commentators began to debate whether light could usefully reach your brain from the device.
Your Brain Can Actually Detect Light
The most obvious question is: does light actually get into your brain, and if so, does the brain know it’s there? Surprisingly, the answers to these questions are: yes, and possible.
Scientists have been studying this first question—whether light can pass through brain tissue—for decades. In a 1963 study, a light detector (sort of like a mini solar panel) was mounted on the end of a needle, and then the needle was stuck into the brain of a sheep, dog, rabbit or rat – in some cases dead. others are alive but under anesthesia. The researchers shone bright light on different parts of each animal’s head. They did some tests indoors, some in sunlight, and also covered different parts of the head with aluminum foil to see where the light was coming from. Their conclusion: Light reaches the brain quite easily, especially through the temples, where the bone is especially thin.
We also know that light-sensitive proteins are found in various parts of the body, including the brain . For example, they may help birds know what time of year it is , but there is still no clear explanation for why humans have these proteins and whether they play a role in seasonal mood disorders.
In 2016, another group of researchers found evidence that light in the ear canals does something noticeable to the brain , but it’s unclear whether it’s good, bad, or if it does anything meaningful at all.
The researchers photographed the skull of a corpse with a Valkee device (similar to the one found on TikTok) in its ears. The light is bright enough to penetrate through the bones and into the brain. However, this is not the same as saying that the device works : “Whether chronic exposure to bright light through the ear canals produces clinically applicable benefits is beyond the scope of this study.”
There is virtually no evidence that these headphones do what they say.
It’s a big leap between “light can reach the brain” and “this will cure your seasonal affective disorder” and that’s where this product gets stuck.
The light therapy headset used on TikTok (the only major brand as far as I can tell) is made by Valkee. Their current product is called HumanCharger and retails for $200.
The company commissioned several studies of their product, and in the early years of their marketing they seemed to rely heavily on them. A 2012 television program in Finland, where Valkee is based, criticized the company over their marketing claims and pointed out to viewers that their research did not hold water. Many do not have adequate placebos, all have conflicts of interest (the authors are company founders and board members), and most have not been published in peer-reviewed journals. At the time, their only peer-reviewed article was in the journal Medical Hypotheses , exploring “radical hypotheses that would be rejected by most traditional journals.”
At the time, the company’s website listed migraines and jet lag among the conditions their product could treat; in particular, the current HumanCharger website avoids such statements. The marketing video shows a woman entering a hotel room as a suitcase rolls behind her, along with a caption saying the device “gives you a boost of energy.” Another shot says the device fights “the blues.”
I don’t buy it
Research since then has not been more promising. One 2014 study , whose authors included Valkee employees and shareholders, claimed that the device lowered people’s scores on depression surveys. But there was no control group; the researchers were simply looking for evidence that people who received the highest dose of light fared better than those who received the lowest dose. They didn’t.
An unrelated group of researchers, experts in the field of chronobiology, tested people’s melatonin levels, subjective sleepiness and their ability to perform attention tasks after using the Valkee device. They found no difference between people who used the device and a “dummy” version that did not emit light. (Visible light, as expected, caused a strong reaction.) They titled their paper: “Extraocular light passing through the ear canal does not have a major effect on human circadian physiology, alertness, and psychomotor vigilance.”
Other studies of circadian rhythms have found no conclusive evidence that our body clocks can be confused by light coming from our ears, behind our knees, or anywhere other than our eyes. Interestingly, our eyes’ ability to perceive daylight appears to be separate from our sense of vision . Many blind people find that their circadian rhythms are out of sync with daylight, but for some, the light-sensing systems remain intact even without vision.
So there’s no conclusive evidence that backlit headphones do anything; and there’s a decent amount of evidence that it’s probably bullshit. I’m happy for everyone who bought this device and feels their lives are better as a result (Lord knows I have my own emotional support placebos), but I would encourage you, dear reader, to save your money.