If you’ve ever had a migraine, you know how debilitating and painful it can be. What’s worse, there’s no cure for these intense headaches, and the effectiveness of migraine treatment can be iffy and a bit arbitrary, depending on the person.
While migraines can cause sensitivity to light — along with a range of other uncomfortable symptoms — a growing body of research suggests a certain form of light therapy may actually help relieve the pain instead of exacerbating it. It’s called green light therapy, and the concept is simple. People are exposed to green light in some form (think: a green lightbulb or a green-lit lamp) with the goal of reducing their migraine symptoms.
It sounds like something out of a sci-fi movie, but there’s some research to suggest this can actually be an effective way to get relief during a migraine. Here, doctors explain.
What Are Migraines?
Migraines can look a little different for everyone, but for the most part, they cause “severe throbbing pain” or “a pulsing sensation,” oftentimes on just one side of the head, according to the Mayo Clinic. The pain can last for hours to days, not to mention it can be accompanied by symptoms such as nausea, vomiting, sensitivity to light and sound, seeing spots or flashing lights (known as a migraine with aura), and temporary loss of vision.
The condition affects more than 29 million Americans, and about three out of four people with migraines are women, according to the U.S. Office on Women’s Health. Despite how common the condition is, people with migraines often struggle to find a treatment that works. Some find success with certain lifestyle adjustments (i.e. changes in exercise or diet), while others see improvement in their symptoms after taking over-the-counter or prescription medication. Some people also get Botox injections for migraines.
The Science Behind Green Light Therapy for Migraines
The therapy was first pursued by Rami Burstein, Ph.D., a professor of anesthesia and neuroscience at Harvard Medical School and vice chairman of neuroscience in the Department of Anaesthesia, Critical Care, and Pain Medicine at Beth Israel Deaconess Medical Center. He tells Shape he began studying green light after exploring the effect of color on photophobia, or the exacerbation of headache by light, in migraine patients.
“Briefly, I tested effects of white, blue, green, amber, and red colors of light on headache intensity and found that [nearly] all colors of light make the headache more painful, whereas a narrow band of green light makes the headache less painful,” explains Burstein. What’s more, if green light therapy is used long enough (30 minutes to a couple of hours), it “often terminates the headache altogether,” he adds.
One of Burstein’s studies, published in the scientific journal Brain in 2016, exposed 69 people to different forms of light during an active, untreated migraine attack. First, the migraine-sufferers established a baseline of their pain by rating their headache intensity on a scale of 0 to 10, describing the location of the pain (i.e. behind the eyes, in the forehead, in the temples, etc.), and indicating whether the headache throbbed or resulted in tender neck muscles. Next, researchers asked them to verbally describe, in real-time, any changes in their headache — including in the intensity of the pain or any onset of throbbing sensations or muscle tenderness — as they were exposed to different intensities of white, blue, green, amber, and red light.
Results showed that nearly 80 percent of participants said their headache got worse when they were exposed to every light color — except green. In fact, “exposure to green light reduced pain intensity” in about 20 percent of participants, according to the research.
Since then, more people have researched green light therapy for migraines and found similar results. In a study published in the medical journal Pain in 2018, researchers analyzed the effects of different light colors in 44 people with active untreated migraine pain, 59 people with migraines who weren’t experiencing pain at the time of the study, and 17 people without a history with migraines. As you might expect, none of the people without migraines reported any pain in response to the different lights. But similar to the findings in the Brain study, the results showed that exposure to white, blue, amber, and red light exacerbated pain in about 80 percent of people experiencing an active migraine attack, while green light only made the pain worse in 40 percent of this group. Of the migraine-sufferers who weren’t experiencing pain during the study, white, blue, amber, and red lights triggered headaches in roughly 16 to 19 percent of the group. Comparatively, green light caused an onset of migraine pain in just 3 percent of people in this group. “These findings suggest that color preference is unique to migraineurs, as it was not found in control subjects [i.e. the people without migraines],” the researchers wrote.
In yet another study published in the medical journal Cephalalgia in 2020, researchers exposed 29 migraine patients to white light for one to two hours every day for 10 weeks. After a two-week break, they were exposed to green light at the same frequency for 10 weeks. The results showed that, while white light seemed to be associated with “no significant change” in headache pain, green light exposure reduced the number of self-reported headache days a month by about 60 percent. And — this is telling — 28 of the 29 people asked to keep their green lights at the end of the study, according to a press release.
How Green Light Therapy for Migraines Works
It seems to work by calming your brain. Burstein says he’s measured the magnitude of the electrical signals generated by the retina (the layer of cells lining the back wall inside the eye, which senses light and sends signals to the brain so you can see) and the brain’s cortex in migraine sufferers in response to different colors of light. In his research, he explains, he discovered that blue and red lights appear to create the largest signals in both the retina and the cortex, while green light seems to generate the smallest signals.
“The brain response to the visual stimulus in green color is much smaller than the response generated in the brain by visions in all other colors,” says Burstein. “And when the brain is less active, it becomes calmer, which might help terminate the migraine attack and allow migraine patients to continue with their daily functions.”
When someone is experiencing a migraine, their brain is “hyperexcitable” compared to when they’re not having a migraine, explains Katherine Hamilton, M.D., a neurologist and headache specialist with Penn Medicine. “It has been discovered that green light leads to less activation of certain brain regions involved in migraine and pain processing compared to other colors, such as blue light,” she says. “This may indicate that green light is able to reduce that excitability of the migraine brain.”
While the benefits seem promising, green light therapy “still needs to be studied in more depth,” notes Dr. Hamilton. But, there seems to be something here, she adds. “There’s definitely strong, concrete evidence based on rigorous scientific studies that green light has different effects on the brain than other wavelengths of light and that green light is less bothersome for people with migraine,” she says. “This is certainly based on more than just anecdotal accounts.”
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How to Use Green Light Therapy In Your Life
It’s not yet clear whether green light can prevent migraines from happening in the first place, but Burstein says the therapy is most likely to be effective during a migraine attack.
There are different green light lamps, lightbulbs, light strips, and more light therapy products available online. Burstein recommends placing a green light lamp high up in your room so that you’re not restricted to one small area. Or, if you’re able to work during your migraine and you find that green light is helpful for you, you can place the light next to your computer. (Try blue-light-blocking glasses along with your green light to filter out light from your screen that could aggravate your migraine, advises Dr. Hamilton.)
If green light therapy works for you, you should start to feel better pretty quickly, says Dr. Hamilton. “Someone might notice that upon entering an environment with green light, their migraine pain and light sensitivity is significantly decreased right away,” she explains. In fact, Burstein says his research suggests that people can really notice the effects within 30 to 60 minutes, although he notes that the maximum benefits are usually reached after two hours of exposure.
Since green light therapy is still being studied, it’s difficult to know exactly what the future of this migraine treatment might hold. “It is unclear whether there may be any long-term effects or cumulative benefit of green light,” says Dr. Hamilton. “It would be necessary to more formally study this green light therapy to determine the short- and long-term effects on migraine.”
But, if you struggle with migraines, there’s really no reason not to try this therapy.