Going Green (Light) for Migraine and Pain: A Conversation with Mohab Ibrahim

By Freda Kreier | March 19, 2024 | Posted in

“Extraordinary claims require extraordinary evidence. Honestly, very few people believed our first paper. There were some good-natured jokes, like, ‘You’re a pharmacologist – why are you playing with light?’ In fact, our lab looks like a dance floor because of all the light we have.

But we got published, we have the data to support our claim, and then other labs from around the world replicated our results. Now it’s more accepted. There are still a lot of skeptics – and rightfully so. It’s something that not many people have done before. Eventually, when the work is replicated, you have to say: ‘Okay, this cannot be a coincidence. There must be something going on.’ ” 

– Mohab Ibrahim

Mohab Ibrahim, PhD, MD, is a doctor, a pain researcher, and a professor in the departments of anesthesiology, neurosurgery, and pharmacology at the University of Arizona, Tucson, US. Among his research pursuits is his work on green light therapy as a way to treat migraine and pain.

In 2020, he was part of a research group that published a paper showing that daily exposure to green light for an hour or two reduced migraine frequency in people living with the condition. Other researchers, including those in the migraine field, have also recently begun to investigate the therapeutic potential of green light.

Ibrahim recently spoke over the phone with Freda Kreier, a freelance science journalist, about the science of green light, its potential as a therapy for migraine and pain, and lingering questions about the approach. The interview has been edited for clarity and length.

Can you tell me about the first time you heard about green light as a pain therapy? How did it capture your attention?

The whole story began almost 10 years ago when I called my brother, who sometimes experiences headaches. Every time I’d ask him how he was doing, he’d say, “Well, I have a headache.”

My response would be, “Go get some ibuprofen or some Tylenol and you’ll feel better!” And his response – which never changed – was, “I just like to sit in my backyard under the trees until I feel better.” I really didn’t think much of it.

Then, one day, I got a headache myself. I was driving to the pharmacy to get something for my headache, and I recalled that my brother feels better when he’s outside. So instead of going to the pharmacy, I went to a park. I was there for maybe 20 or 40 minutes, and my headache got better.

Mohab Ibrahim

Mohab Ibrahim

I went back to my office, and I started thinking about it. Maybe the trees were releasing some chemicals in the air that may have analgesic properties. The problem with that idea was that to test each and every chemical was going to take several lifetimes’ worth of research. So I thought, “There has to be something in common between San Diego – where my brother lives – and the park in Tucson.”

So I started with the very basics: The color green. Most parks are green, so it could be color. I went online and saw that no one had done anything with green light. Then we got some rodents, exposed them to green light, and evaluated their pain response. Much to our surprise, green light was as effective as opioids in decreasing their pain.

I couldn’t believe it. So we repeated the experiment five times, and every time we got the same result. That’s when we decided that this was not a coincidence. These were real results.

The idea that green light reduces pain sounds very New Agey. How does it work?

We did a couple of experiments to understand the mechanism. The first step was to see whether green light was acting through the skin or the eyes.

We obtained some rats, and we figured that to understand this first question, we’d have to cover the skin or the eyes and see how that applies. We tried to fashion some suits for the animals to cover their skin so just their eyes were exposed. Then we came up with the idea of space helmets that will cover their eyes and leave their bodies exposed.

Needless to say, that didn’t go far.

Eventually we came across a paper that fashioned contact lenses for rats. And we thought, let’s give that a try.

I will not say how many times we got bitten by the rats. But we turned science into art, and we were able to get the rats to trust us enough to get contact lenses on their eyes. We did one experiment where we covered the rats’ eyes with black lenses; the entire rat is exposed to light, except through the eyes. And when we did that, green light was not effective. So that gave us a clue that the effect was through the visual system.

Now the challenge was to connect the visual system to the pain centers in the brain. There are several possibilities for decreasing pain: One is to control the endorphin system, and the other is to control inflammation of the nervous system. What we noticed [see here and here] is that with green light, there was an increase in the concentration of beta-endorphins, which are known analgesics. And we found that green light also decreased neuroinflammation. There are still far more questions than answers. But it’s promising, and we like it.

Why would green light decrease pain in the first place?

The simple answer: Your guess is as good as mine. It could be that green represents trees, grass, food, light, and water. It might be an indication that something good is happening. So maybe we evolved to be attracted to the color green. But again, this is just a hypothesis as to why green light is so soothing and so good at decreasing pain.

Tell me about your work testing green light in people with migraine.

These were migraine patients who failed all available therapies, including Botox and the new CGRP [calcitonin gene-related peptide]-based therapies, and they basically had no other options available to them. We exposed them to green light and saw a 50% to 60%  reduction in pain intensity and frequency of migraines. They also experienced improved sleep, quality of life, and decreased anxiety and depression. We did another clinical trial with fibromyalgia, and we saw the same results as in migraine.

We looked at other pain conditions as well, but we don’t have enough patients to publish the data yet.

How do other researchers react to these results?

Extraordinary claims require extraordinary evidence. Honestly, very few people believed our first paper. There were some good-natured jokes, like, “You’re a pharmacologist – why are you playing with light?” In fact, our lab looks like a dance floor because of all the light we have.

But we got published, we have the data to support our claim, and then other labs from around the world replicated our results. Now it’s more accepted. There are still a lot of skeptics – and rightfully so. It’s something that not many people have done before. Eventually, when the work is replicated, you have to say: “Okay, this cannot be a coincidence. There must be something going on.”

If green light is so effective, why isn’t it further along in clinical development to treat migraine and other pain conditions?

If you go to Google right now, you will find people who are making claims that they have green light-based products that can help with pain. So this is currently commercially available. But how many of these products are FDA approved? Zero.

If you say you’re going to commercialize green light, what is your incentive, as an investor, to commercialize something already available? Also, to get FDA approval, you have to conduct clinical trials. These trials tend to be very expensive. We’re trying to get funding from institutions and investors. But people will ask, “Okay, let’s say the trial is positive and you get FDA approval – what’s the return on investment?”

That’s one aspect. The other is that there are still a lot of skeptics, despite everything that’s being published. Investors don’t want to put millions of dollars into a project that has not gained widespread acceptance yet. However, as more and more peer-reviewed research is published, the balance will tip towards green light being more acceptable and less risky for the public and investors. That’s my perception. I’m not a businessman.

What do you think green light treatments might look like in the future?

We’re approaching it from several angles. People have different preferences. It really doesn’t matter what the source of light is as long as it gets to the eyes – whether through contact lenses, goggles, or light bulbs. What matters is that it gets to the eyes.

What would you like clinicians and researchers to know about green light as a potential therapy?

My patients are running out of options. As a physician, I think of two things: What are the risks, and what are the benefits? And what are the risks associated with green light therapy if used correctly? Our patients didn’t report any side effects.

On the other hand, what are the potential benefits? Well, we have already shown benefits in both animal and human studies. And what happens if people don’t get better from this therapy? The answer: Probably nothing. They will most likely end up with a decorative light no different from a Christmas light.

Most medications come with side effects. And this is when I have to think twice. So it’s a risk-benefit ratio. And if it doesn’t work, no one gets hurt. That’s all.

Freda Kreier is a freelance science journalist based out of Washington, DC.

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