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The Lure of Light Therapy

Companies and biohackers are running with the science behind the healing potential of light therapy

Credit: robyvannucci/E+/Getty

InIn a recent episode of the Ben Greenfield Fitness: Diet, Fat Loss and Performance podcast, Twitter CEO Jack Dorsey shared his daily routine for living healthy. The episode went viral when Dorsey revealed that he eats only one meal a day (and sometimes less on weekends). But another aspect of the Silicon Valley entrepreneur’s routine is his use of light as therapy. Dorsey says he takes walks to work in the morning sun and uses infrared light bulbs and saunas. Other notable figures like NHL player Duncan Keith and supermodel Bella Hadid also say they use light therapy.

In the past few years, multiple at-home light therapy startups have launched, and mainstream beauty companies have introduced red light products. While red light therapy has all the trappings of a new health trend — it’s Instagrammable, non-invasive, and applicable to many issues — the science behind it has existed for decades.

For many people, the idea of light therapy for the mind is familiar. The most well-known example is the light box. These devices exude bright white light, which is absorbed through the retina and goes on to stimulate cells in the brain. Since the 1980s, light boxes have been used to treat seasonal affective disorder (SAD). Using light therapy for physical health is perhaps less intuitive.

Photobiomodulation therapy (PBMT) is a kind of light therapy that uses specific wavelengths of red light to penetrate tissue and stimulate cells. Studies suggest that red light therapy can speed wound recovery, relieve pain, reduce inflammation, stimulate hair growth, and treat certain kinds of acne.

Scientists still don’t completely understand the cellular and molecular dynamics underlying results like these. What they do know is that photons of red light are absorbed by an enzyme in mitochondria, the cell’s energy factory. This spurs a metabolic process that allows the mitochondria to produce more adenosine triphosphate (ATP), a molecule that fuels chemical reactions in the cell and is thought to increase a person’s energy levels.

In 1967, Hungarian physician Endre Mester accidentally discovered photobiomodulation as we know it today. While attempting to recreate an American experiment in which a ruby laser destroyed a tumor in a lab rat, Mester stumbled across the therapeutic benefits of certain wavelengths of red light. Unaware that the laser in his lab was far less powerful than the one that had been used in the original experiment, Mester pointed the light at the implantation site. Instead of destroying the tumor, Mester’s low-level laser unexpectedly helped the rat’s wound heal.

Low-level laser therapy, as it came to be called, remained the primary way to achieve photobiomodulation for decades. But lasers are expensive, and their beams are limited to a small target area. Though light-emitting diodes (LEDs) were invented in 1962, it wasn’t until the 1990s that the potential medical applications for LEDs became clear. In a NASA program originally designed to stimulate photosynthesis in plants, scientists perfected LED technology and realized that by using LEDs, the benefits of the sun could be recreated over a wide area inexpensively and with limited heat.

“What’s important is the color of light, so the wavelength, and the ability to deliver it in a sufficient quantity, over a sufficient time course in order to achieve a biological effect.”

When red light LED devices appeared commercially a few years later, interest in light therapy swelled. In 2009, celebrity aesthetician Joanna Vargas patented her design for an LED bed and started offering sessions at New York and Los Angeles spas. A few years later, red light therapy startups like SaunaSpace and Joovv introduced at-home devices. SaunaSpace, which makes red light therapy products with incandescent bulbs, promotes its lamps as free from “killer wavelengths,” like those emitted by the sun that cause sunburns and raise a person’s risk for skin cancer. Joovv delivers light from what it says is the “optimal window” of wavelengths.

Both LEDs and incandescents are capable of emitting light that can be absorbed on a cellular level, says Dr. Raymond Lanzafame, research associate professor at SUNY Buffalo and executive editor of Photobiomodulation, Photomedicine, and Laser Surgery (he has also advised on commercial applications). “What’s important is the color of light, so the wavelength, and the ability to deliver it in a sufficient quantity, over a sufficient time course in order to achieve a biological effect.”

Proponents of red light therapy argue that it offers a shortcut to a recharged self. Biohackers like Dave Asprey and Ben Greenfield tout red light therapy’s ability to counter the effects of aging and regulate hormones. Red light therapy is noninvasive and available at a number of price points ranging from $40 to more than $5,000. Unlike drugs or in-office treatments, at-home LED devices are a one-time purchase, although suppliers have tried to work around that. When Neutrogena released a $40 LED face mask a few years ago, the company designed the product in two parts: the mask, and a battery-powered “activator,” programmed to expire after 30 sessions. Replacement activators retail for about $15.

But are any of these products more beneficial than spending time outside?

“Funnily enough, you actually get more energy from the sun,” says Dr. Michael Hamblin, principal investigator at the Wellman Center for Photomedicine at Massachusetts General Hospital, who has served as a scientific adviser for several red light therapy companies.

If you lie in the midday sun for an hour, unclothed and sunscreened, at a “decent latitude,” Hamblin says, your body will absorb a billion joules of optical energy. This energy boosts ATP levels in the cells and stokes energy production in the mitochondria for hours after. It would take several hours to absorb that much energy from an LED or incandescent product.

Companies can’t claim that their light therapy products effectively treat a disease without a randomized, controlled clinical trial, and such studies take time and are expensive. For this reason, Hamblin says, there hasn’t been a lot of progress in getting red light therapy medically approved for all possible uses.

Scientists know that red light helps activate some parts of the body, like the stem cells in hair follicles. But they don’t know exactly how far those benefits extend. Instead of running trials to provide evidence for additional applications, companies offering the therapy tend to draw on existing research, using terms like “optimization” and “rejuvenation” to imply holistic benefits.

Lanzafame and Hamblin agree that PBMT products have a place in the home and that ultimately, wider awareness of the benefits of red light therapy could be a good thing. In some cases, like for acute pain, handheld devices may offer a less invasive solution than daily medication. But for full-body revitalization, given the need for more research and the cost (large devices start around $1,000), simply taking a walk outside on a sunny afternoon may still be a better deal.

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