Green Light for Migraines cover image

For those who suffer from migraines, you know that sensitivity to light – or photophobia- just comes with the territory. All light should be avoided at all costs.

But what if I told you that there is one color of light that can actually help?

Harvard and the University of Arizona have been doing the darn thing from rat studies to human trials. They’ve been able to show that green light therapy can treat migraine pain and also reduce the number of days you experience migraine.

WILD!

But, if you’re like me, you want to know just how and why these results happen.

It sounds a little like magic, or coincidence, or if anything else…

a product of the placebo effect.

Shrek in disbelief

But hear me out! We’re about to take a deep dive into the world of green light therapy that may turn you into a believer.

What is Green Light Therapy?

If you’re new here, all you have to do is sit in front of a light source emitting a narrow band of green light for a few hours a day, and BAM! Pain reduced!

Now, it can’t be just any old green light. The room should be dark with as little ambient light as possible, and the green light must be in the range of around 525 nanometers, give or take 10 or so nanometers.

Does Color Really Matter?

YES! The whole trick to green light being as effective as it is depends on the narrow band of green light only.

allay lamp green light spectral power distribution graph
Light spectrum graph from the Allay Lamp

Colors in the blue and red spectrums are more reactive with the photoreceptors in our eyes and therefore produce more of a pain response when we are exposed for extended periods of time.

Green light does not have this effect so it’s not as stressful to our brains.

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You can learn more about Photophobia and how different colors affect our eyeballs in our article What Color Light Helps with Headaches?

Why Light Makes Migraines Worse

Alright, now that we have a basic understanding of green light therapy, you’re probably wondering:

Ok…but how could this possibly help with my migraine? It’s still light, isn’t it??

Well, we’re going to start at the very beginning and see what researchers today know about the cause of migraines. This will give us some background on why only green light therapy, or blocking of blue and red light, can help alleviate light sensitivity.

What Causes Migraines

Headache researchers are still working on finding the root cause of migraines. It used to be blamed solely on variations in blood flow – which does cause the pain- but they want to know what causes those variations to occur.

In an article out of the UCLA Department of Neurology, they provide a modeled hypothesis of the “sequence of events in a migraine” based on their research.

Hypothetical causes of migraines diagram
Don’t worry if all this jargon doesn’t make sense…I will explain.

What we can see from this diagram is that hormonal, genetic, and/or environmental factors can cause a “dysregulation,” or imbalance, in the cortex and possibly the brainstem – this is where our senses are housed.

This imbalance creates a stress response where your body releases hormones (such as serotonin) that regulate your blood pressure by constricting or dilating blood vessels.

This can bring on the throbbing pain often felt in migraines. (R)

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The cortex is used for higher processes such as emotion, memory, and the senses; and the brain stem contains 10 out of 12 cranial nerves which process sensation and control your facial muscles.

In this excited state, any further stimuli (such as light) will increase the brain’s demand for nutrients which increases blood flow along with the sensation of pain. Your body will signal you to avoid lights and/or sounds resulting in photo/phonophobia.

It’s important to remember that no two people may have the same migraine triggers. Such triggers can be:

  • Hormonal fluctuations – mainly estrogen which is why women experience more migraines than men
  • Flashes of light/Strobes
  • Foods or smells
  • Lack of proper sleep
  • Stress or other strong emotions

What we can say is that for some people, light is the main trigger; but for a lot of people, it usually just worsens an existing migraine. So green light therapy may not cure you, but it can be used to alleviate the pain and reduce its frequency.

How Our Eyes Detect Light

When we are exposed to light, the rods and cones in our eyes are responsible for detecting color and visual patterns which it sends to the brain to interpret into vision, or sight. We may have learned this in grade school biology.

HOWEVER!

Research shows that even people who are blind or color blind – those without fully functioning rods and cones- can still respond to light stimulation and even benefit from green light therapy!

This is where we get into the territory of intrinsically photosensitive retinal ganglion cells– or ipRGCs.

diagram of retina showing rods, cones, and ipRGCs

ipRGCs are cells located on our retinas that detect light via a photopigment called melanopsin. This information is mainly used for non-visual processes such as altering our circadian rhythm, release of hormones, and cognitive functions.

A lot of big words, I know, but stay with me!

ipRGCs are most responsive to shorter wavelengths of light – aka blue light. In today’s world we are constantly surrounded by sources of blue light such as phones, TVs, computers, LED light bulbs, etc and the strain on our eyes and brains is evident.

A lot of us have heard of, or use, blue-blocking devices; but you might notice that they tend to veer toward the orange/red end of the spectrum, completely ignoring the green!

But red is also a color that our bodies are highly reactive towards. Just think about red light therapy – it is used to increase the speed of wound healing/overall regeneration of our cells.

You might think this would be perfect for those suffering from a migraine, but working harder and increasing neural activity is not something an already overly stimulated brain wants. It just wants to rest, relax, and rebalance itself.

Show me the green light jerry mcguire meme

How Green Light Helps with Migraines

Green light is what is referred to as a “neutral stimulus.” Neutral stimuli, in reference to light, do not cause a massive shift of photopigments – remember melanopsin?- so they keep your receptors in equilibrium.

That’s not to say that it doesn’t affect our brains at all, just that it’s not creating that imbalance that can bring on a headache or migraine. In fact, it can actively work against your system going out of balance in two major ways:

By decreasing the melanopsin response and by acting as an opioid.

Green Light Decreases the Melanopsin Response

There was a study conducted on melanopsin response to blue light after red light exposure, and they also got some interesting results when they threw a mid-band green into the mix.

Melanopsin response after blue, red, and mid wavelength light

As we can see, the response to blue light was increased by 60% post-red light exposure compared to darkness. So, much like we’ve seen in rat studies, our sensitivity to stimuli can be increased by longer wavelength red light.

Now, when they throw in a mid-band green light (it doesn’t look as green as it should but 530nm is very much green, trust me) there is actually about a 9% decrease in response to blue light!! Even after the red light exposure that follows!

So if you are someone who suffers from photophobia, or if light is one of your triggers, using green light therapy could help to decrease your melanopsin response and thus decrease your level of pain!!

Sorry for all the exclamation points but isn’t this exciting?? I’m geeking out over here!

OK, ok. Calming back down.

Green Light Can Act as an Opioid

Another way that green light can help with pain is that it has the potential to act as an opioid.

Opioids work by binding with pain receptors so that the pain messages being sent by the brain can’t get through. In other words, they block your brain from detecting pain. (Ba dum tchh)

From the same Mohab M. Ibrahim (this guy is on a roll!) from the University of Arizona, a study of rats shows higher levels of B-endorphin and Proenkephalin in the Cerebral Spinal Fluid (CSF) after green light exposure (below).

Opioid effects of green light study results

These hormones bind to opioid receptors and block the pain from being detected. They were not found in the blood (serum) but were found in the CSF which shows the connection between our photoreceptors and the spinal cord.

While I know that we are not rats, all the other science seems to translate over to humans in regards to this green light therapy. So it might only be a matter of time before we detect these levels in humans as well!

Effectiveness of Green Light in Human Trials

Speaking of humans! That’s us!

These are the studies that are used by most green light therapy companies to back up their claims of effectiveness. We will see that they do show green light helps decrease light sensitivity, pain, and the number of migraine/pain days.

Only, you now have a better understanding of why. So, congratulations smarty pants!

The Harvard Study

This is the one you’ve probably already seen or heard of. Most green light therapy companies and other green light blogs mention this study when discussing the effectiveness of green light therapy.

It was published in the journal Brain in 2016, and Harvard also posted a summary article you can peruse.

Out of the 69 patients enrolled, only 41 completed all of the assessments. So it’s a relatively small sample size. More studies will need to be repeated in order to actually say that this is an overarching theme and not just a placebo.

Each patient was placed in a dark room, to establish a baseline pain rating, and then exposed to increasing intensities of light in white, blue, green (530 ± 10 nm), amber, and red. They also had breaks in between to reestablish the baseline for reference.

Results:

In conclusion, this study demonstrates that green light is least likely to exacerbate migraine headache and that at low intensities it may even be therapeutic by reducing the headache intensity.

Migraine photophobia originating in cone-driven retinal pathways – Brain

These charts represent the study results in terms of (A) the percentage of patients who either experienced an increase or decrease in pain intensity compared to the brightness level

and (C) the numerical change in headache intensity per brightness level as reported verballed by the participants who did experience a change.

Their findings showed that in around 80% of the participants, all colors – except green which was around 40% – experienced increased intensity of pain, as compared to the baseline, regardless of the brightness setting used.

Harvard study results bar graphs

HOWEVER, it does mention, and as we can see, it was mainly with higher brightness levels that green seemed to increase pain from baseline by around 5%, compared to the other colors increasing by 15-20%.

It was only at lower brightness settings that green light appeared to have the pain-diminishing effect – up to 15% – but this was only in about 20% of participants. It may sound small but this was a much higher percentage than they were expecting to find.

This is why in their conclusion they state verbiage like “green light is least likely” and “may even be therapeutic.” The sample size is small and clearly, only a minority of people actually experienced the pain-relieving effects, but the results are still there.

Green light therapy does indeed have pain-diminishing effects on patients who suffer from photophobia with migraines. You could be that 20%!

Studies from the University of Arizona

Now Harvard gets all the love from their study, but more recently the University of Arizona with Dr. Mohab M. Ibrahim and Dr. Amol Patwardhan have been churning out the green light research like madmen.

Migraine Patient Study

In 2020 they published a study in the SageJournals, and UofA also posted a summary article discussing the implications.

It was a smaller sample size of 29 patients – 7 of which experienced episodic migraines and 22 had chronic migraines. They were grouped as such.

Participants had 1-2 hours of white light exposure per day for 10 weeks, a 2-week rest period, and then 1-2 hours of green light (525 nm) exposure per day for 10 weeks.

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Those who suffer from chronic migraine (CM) have 15 or more migraines a month.

Those with fewer than 15 a month are categorized as having episodic migraines (EM).

These researchers also tried to keep their patients as blind as possible to limit the placebo effect by not telling the groups which light was the experiment. They couldn’t blind the color but they could hide the intent!

The main goal was to measure if the number of headache days per month decreased as a result of the therapy. They also measured secondary outcomes such as headache intensity, effect on sleep, work, chores, exercise, etc.

Results:

The study separated those groups with CM and EM and then also offered results from the two groups combined.

Sagejournal Arizona study results

In this chart, we see white light exposure only resulted in a reduction of maybe 2ish days a month overall. This was noted as “not significant.” However, the green light had a massive reduction in headache days in all groups – around 60%!

With the secondary outcomes, we see the same kind of results. The green light exposure has massive percentages of improvement compared to the white light across the board.

Sagejournals Arizona Study secondary outcomes results

What’s also really cool is that at the end, they offered the green LEDs to the participants to keep, and all but one said yes. Even though their headache days went down from 5 to 0 in their study journal, they only perceived a 20% improvement so they didn’t think it was worth it to keep. Their loss!

Fibromyalgia Patient Study

Now our same Arizona friends didn’t want to stop at just migraine relief. Oh no! They wanted to test therapeutic green light on all kinds of chronic pain conditions including fibromyalgia.

In 2021 they published this study in PainMed which tested green light on 21 adult participants suffering from fibromyalgia.

The protocol was the same as their migraine study with white light 1-2hrs/day/10 wks, a 2-week break, and then green light for 1-2 hrs/day/10 wks.

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Fibromyalgia is a disorder that causes widespread pain along with issues with sleep, mood, memory, and more.

The cause remains unknown and there is no cure – only pain management.

The primary goal was to see if there would be a drop in the intensity of overall pain. Secondarily they recorded any changes in the frequency of episodes, duration, sleep, quality of life, and more.

Results:

I’ll bet you can already guess the outcomes they got.

Surprise! Green light exposure made a significant difference in pain scores in all categories.

Fibromyalgia study primary results

Even the secondary outcomes gave the same results. A marked improvement after the green light compared to the white light.

Fibromyalgia study secondary results

There were a bunch of other charts and graphs in the study that you can check out for yourself if you need more assurance but since they all look like these, you get the point. There’s improvement and a decrease in pain all around.

How to Use Green Light Therapy at Home

Hopefully, by now you understand the science behind green light therapy and believe that it is a safe and effective treatment of light sensitivity and overall perception of pain.

If you are someone who suffers from chronic pain or photophobia, you can experience this relief right from the comfort of your own home!

No more dangerous prescriptions or over-the-counter pills with side effects that leave you feeling less than human.

Green light is just that, a light. So there are no side effects and a relatively cost-effective treatment.

Green Light Therapy Lamps

The simplest way to experience green light therapy at home is to get a therapy lamp.

There are a few companies that have developed devices that emit the specifically narrow band green light needed – Hooga, Allay, and NorbRelief Bulbs.

To find the one that best works for your budget and needs, we have compiled all of their information and recommend our favorite in our article The Best Green Lights for Headaches and Migraines.

The way to use these lamps is to sit in a darkened room with just the green light on for 1-2 hours a day for a couple of weeks. Make sure you are 1-2 meters from the lamp and don’t stare directly at it…or fall asleep… you gotta be awake to experience the results.

Migraine Glasses

If you’re more someone who’s constantly on the go and you don’t really have time to sit in front of a lamp for a few hours a day, there are a few migraine glasses options that might be better suited to your lifestyle!

Migraine glasses work best by filtering out the blue and red wavelengths of light, leaving only the green to come through the lens.

Here are a few to try out for yourself!

Filters mainly blue light with FL-41 lenses – not red

Green-tinted glasses – not much science behind them

Blocks blue and red light but has a green tint

Filters blue and red light with little color distortion

Just wear a pair of these bad boys while you’re out and about, or until your symptoms have gone. There is no time limit so you don’t have to worry about wearing them too long.

  • Learn more

For our full review of the Migraine glasses listed above, check out our article on The Best Migraine Glasses of 2023.

Forest Bathing aka Get Outside!

Forest bathing is an idea that originated in Japan and recognizes all of the positive effects that come with immersing yourself in nature. Not to mention…leaves are green.

And it’s free!

Leaves just so happen to absorb all of those pesky red and blue wavelengths which leaves (ha…pun actually not intended) green light to be reflected back at us. [R]

spectral power distribution graph of sunlight through leaves
This is a graph comparing the light spectrums of sunlight vs that sunlight filtered through 3 leaves that we picked up on a walk around our neighborhood one day.

As you can see, the leaves allow light in the green spectrum – the 500-570nm range – to pass through to our eyeballs. This is why we see leaves as green. The spike at the end is longer wavelength reds going into the infrared range which we can’t see.

So if all else fails, go somewhere with lots of leaves, find a shady spot, and relax!

Rafiki Relaxing

Conclusion/TLDR

spongebob exhausted meme

WHEW!

That was a lot of information, but I’m glad you were there for the ride!

Now, if you skipped down to this section and didn’t look through the whole article… I don’t blame you… but you missed some good nuggets. Go back up and check it out!

Overall, studies show that Green Light Therapy is a safe and effective treatment option for migraines, headaches, fibromyalgia, and other chronic pain conditions. There are no side effects and there are relatively cost-effective ways to experience it at home.

Green light appears to dampen our response to other light stimulation, cause very little visual stimulation and brain power to process itself, and also produces hormones in our bodies that bind to receptors to block pain signals.

Wild. I know.

So get outside with your glasses, hug a leafy tree in the forest, or get a green lamp to put in your room for those moments when the pain is too much. It might just take a couple of hours a day to start you on your journey to a pain-free life!

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4 Comments

  1. Thank you for sharing this informative article!! I had no idea about the green light! Do you know if green lights have long term benefits of prevention or is it more of an acute therapy / pain reduction?

    1. Hello Karis,
      Thank you for reading, and an excellent question! I will update the article but in short, yes green light does seem to have long-term benefits! I will go back through and include this information 🙂
      Thank you!

  2. Arguably the most convenient way to take advantage of green light therapy is to get a set of glasses with green lenses