Infrared Light for Joint & Muscle Pain Explained
Share
Infrared Light for Joint and Muscle Pain: What the Science Actually Shows
The Quick Answer
Near-infrared light (fotobiomodulasjon) has solid research support for joint and muscle pain. A 2024 meta-analysis in Physical Therapy found photobiomodulation reduces pain and disability in knee osteoarthritis compared to placebo. It works through three documented mechanisms: supporting mitochondrial ATP production in inflamed tissue, releasing nitric oxide to improve local blood flow, and reducing pro-inflammatory cytokine signalling. Near-infrared wavelengths around 850nm are necessary to reach deeper structures like joints and muscle belly. Red light at 660nm is effective for superficial tissue only. Consistent daily use over six to twelve weeks is needed for chronic conditions.
Les den kortere norske versjonen her: /blogs/norsk/infrarodt-lys-leddsmerter-muskelsmerter
There's a version of chronic pain that never quite makes the news.
Not the dramatic kind. Not the kind that lands you in A&E or produces a diagnosis that sounds significant enough to mention at dinner. The version I mean is the quieter, more persistent variety. The shoulder that's been "a bit off" for two years. The knee that you've learned to work around without consciously deciding to. The lower back that doesn't stop you entirely but dictates a hundred small decisions a day that add up, slowly, to a smaller life.
I know this directly. I have rheumatoid arthritis, and managing it has been one of the more instructive experiences of my adult life, not because it's dramatic (it isn't most of the time) but because it forced me to understand inflammation at a level I wouldn't have bothered with otherwise. What I found when I went looking is that near-infrared light therapy is one of the most biologically sensible interventions available for chronic inflammatory pain, and it's substantially better supported by research than most people realise.
I want to explain why. Not at the level of "red light reduces inflammation" (which tells you nothing useful), but at the level of what is actually happening in the tissue, and why that matters for whether it will work for you.
The Problem With How We Think About Inflammation
Most people understand inflammation as the enemy. Red, swollen, hot, painful tissue that needs to be suppressed. Anti-inflammatories, ice, rest. Calm it down and you're fine.
That's not wrong exactly, but it's a deeply incomplete picture of what's actually going on, and the incompleteness matters because it leads to treating inflammation as a single problem when it's at least three overlapping problems running simultaneously.
The first is an energy deficit that almost nobody talks about. Inflamed tissue has genuinely impaired mitochondrial function. The cells in an inflamed joint aren't just signalling distress, they're also producing less ATP than they need to carry out the repair processes that would actually resolve the inflammation. Think about what that means: the very process that should be fixing the problem is running underresourced precisely because the problem exists. Less energy means slower resolution, means persistent inflammation, means mitochondria remain impaired. It's a self-reinforcing loop, and breaking it requires addressing the energy side, not just the signalling side.
The second problem is circulation. Inflammatory processes actively reduce local blood flow to the affected tissue. Less oxygen in, less metabolic waste out. The local environment becomes progressively more hostile to healing over time, not less. This is one reason chronic pain states are so much harder to shift than acute ones. The tissue has been marinating in its own waste products for months or years.
The third is the cytokine signalling loop itself. Inflamed tissue releases pro-inflammatory cytokines (IL-1, IL-6, TNF-alpha are the main players here) that instruct the immune system to produce more inflammation. In acute injury, this is adaptive and useful. The immune system is supposed to show up in force after genuine tissue damage. In chronic conditions, this loop becomes self-perpetuating long after the original trigger would have been resolved. The immune system keeps receiving "more inflammation needed" messages from tissue that is inflamed partly because of the immune system's previous responses.
Near-infrared light addresses all three. Not through one mechanism but through several, which is part of why the clinical results look as good as they do.
What the Research Actually Shows
Let me be specific here rather than vague, because vague claims about research are how a lot of nonsense gets laundered into wellness marketing.
A 2024 systematic review with meta-analysis published in Physical Therapy examined ten randomised placebo-controlled trials involving 542 participants with knee osteoarthritis. The conclusion was that photobiomodulation can reduce pain and disability in this population compared to placebo. Ten randomised trials. 542 people. Placebo-controlled. That's meaningful evidence, not a few enthusiastic case reports.
A comprehensive review in the International Journal of Molecular Sciences in 2023 examined the mechanisms and clinical evidence for photobiomodulation in both rheumatoid arthritis and osteoarthritis specifically. It identified five key cellular mechanisms through which near-infrared light exerts effects on joint tissue: regulation of angiogenesis (blood vessel formation), stimulation of ATP production in cells, modulation of arthritis-related gene expression, regulation of joint enzyme secretion, and modulation of cytokine expression, including reducing the pro-inflammatory cytokines I mentioned above.
Dr. Michael Hamblin at Harvard has published on photobiomodulation mechanisms for over two decades. His work, alongside that of Dr. Tiina Karu who essentially established the cytochrome c oxidase absorption mechanism in the 1980s, underpins most of the modern clinical research in this field. This is not alternative medicine territory. It's photobiology with a substantial peer-reviewed literature behind it.
A 2022 systematic review of infrared radiation for musculoskeletal conditions found evidence across knee osteoarthritis, fibromyalgia, chronic low back pain, myofascial syndrome, and sacroiliitis. The breadth of conditions responding to the same basic mechanism tells you something important: this isn't a single-condition intervention. It's a cellular intervention that happens to be relevant wherever inflamed tissue with impaired mitochondrial function exists, which is most chronic pain conditions.
The Mitochondrial Mechanism in Plain Language
Cytochrome c oxidase is an enzyme in the mitochondrial electron transport chain. It is the primary chromophore (light absorber) for near-infrared wavelengths in biological tissue. When it absorbs photons in the 600 to 1000nm range, it improves the efficiency of electron transport, which drives more ATP production.
More ATP means cells that have been operating at reduced capacity get more fuel. The repair processes that inflammation was preventing from running properly can now run. The resolution of inflammation that was being blocked by energy deficit becomes possible again.
This is why wavelength specificity matters, and why "infrared" as a general category is too vague to be useful when choosing a device. Far-infrared (the kind produced by saunas and heat lamps) works through a thermal mechanism, warming tissue. It doesn't have meaningful photobiological effects at the cellular level. The photobiomodulation mechanism operates specifically in the 600 to 1000nm range, red and near-infrared, because that's where cytochrome c oxidase actually absorbs.
And within that range, penetration depth varies significantly. Red light at 660nm penetrates approximately 5 to 10mm through tissue. Good for superficial muscles, tendons close to the surface, skin. Near-infrared at 850nm reaches 20 to 30mm, actually getting down to muscle belly, the synovial membrane surrounding joints, and periosteum (the tissue covering bone) in some cases. For a knee, a shoulder, or a hip, the maths is simple: you need near-infrared to reach the problem. Red light alone won't get there.
The nitric oxide release mechanism is the second major pathway and is probably responsible for a large portion of the pain relief that people report. Near-infrared light releases nitric oxide from haemoglobin in the local blood supply. Nitric oxide is one of the most potent vasodilators in the body. It expands blood vessels and increases local blood flow dramatically, more oxygen in, more nutrients in, more inflammatory waste out. This is the same mechanism that makes athletes' recovery times shorten with regular near-infrared use, and it's directly relevant to the stuck circulation pattern I described earlier that makes chronic joint pain so resistant to treatment.
Why Norwegian Winter Makes Chronic Pain Measurably Worse
This is something I have direct personal experience of, and which also makes complete biological sense once you understand the mechanism.
Norwegian winter systematically removes from your environment the wavelengths that your mitochondria depend on. Full-spectrum summer sunlight delivers abundant red and near-infrared light daily. Indoor LED lighting in winter delivers almost none of these wavelengths. The LED peak is in the blue region of the spectrum. Red and near-infrared are barely present.
The consequence over months is a slow, accumulative reduction in cellular energy capacity across all your tissues, not just skin. Your joint tissue, your muscle tissue, your connective tissue, all of it is operating on progressively less mitochondrial fuel as winter continues. For someone with healthy joints this is a background drag. For someone with an existing inflammatory condition it's genuinely significant. Reduced energy availability in already-inflamed tissue means slower resolution of flare-ups, lower pain threshold, longer recovery from activity, and the general "everything hurts more from November onwards" experience that anyone with arthritis, fibromyalgia, or chronic back pain living at Norwegian latitude knows very well.
It's not the cold, or at least not primarily. It's the light. The cold is a secondary factor. The spectral impoverishment of the indoor light environment is the primary biological driver of that seasonal worsening. Which is also why near-infrared light therapy through winter isn't just about treating specific episodes of pain. It's about maintaining a baseline cellular energy level that the environment is actively depleting.
The Grounding Layer
I want to mention grounding (jording) here because it addresses a different dimension of the same underlying problem, and the combination is more effective than either alone.
Free radical accumulation (reactive oxygen species) is a significant driver of chronic inflammatory tissue damage. The earth's surface carries a net negative electrical charge, a large reservoir of free electrons. When your body is in direct conductive contact with the earth, those electrons transfer into your tissues and neutralise reactive oxygen species, functioning as a direct antioxidant effect that doesn't require any metabolic processing.
A 2015 review by Oschman, Chevalier and Brown in the Journal of Inflammation Research examined multiple grounding studies and found grounding reduces markers of chronic inflammation, improves cortisol rhythm, reduces pain, and speeds wound healing. The free electron mechanism is the proposed pathway, and it's mechanistically plausible in a way that some grounding claims are not.
I sleep on a grounding sheet and I notice what happens to my arthritis on the days I've been travelling and slept in a standard hotel bed. Not dramatic. Not immediate. But by day three without it the baseline level of inflammation is measurably higher. It took me a few travel trips to confirm it wasn't placebo, because I kept noticing before I consciously registered the absence of the sheet. That's the kind of evidence that matters to me personally.
Near-infrared light addresses cellular energy. Grounding addresses oxidative stress. Chronic inflammation runs on both. Using both simultaneously is a more complete approach than either alone, and neither interferes with medical management if you're also working with a doctor.
What to Actually Expect
Acute problems, meaning tissue that has been inflamed for days to weeks, respond relatively quickly. A muscle that's been aggravated for two weeks after a run can see meaningful improvement within a week or two of consistent daily use. The mitochondria haven't been impaired long enough to require extended repair.
Chronic conditions are different. Six to twelve weeks of consistent daily or near-daily use before you have a fair picture. Not because the biology is slower, but because you're working against an established pattern of impairment. The tissue has been energy-depleted and inflamed long enough that the reversal takes time even when it's working. Most people who try near-infrared light for chronic pain and give up after two to three weeks are stopping just before the results would have become noticeable. That's not a criticism. It's a predictable consequence of the biology being slower than people expect.
For specific joints, portable devices allow close-contact application at the target site. Proximity matters for depth of penetration, so pressing a device against a knee or shoulder gets better tissue delivery than treating from a distance. For lower back, multiple areas, or whole-body maintenance, a panel covering a broader surface area is more practical and typically delivers higher irradiance.
One honest final note that I'll repeat because it matters: movement, sleep and diet all interact significantly with chronic pain. Near-infrared light addresses the cellular energy and inflammation dimension. Grounding addresses the oxidative stress dimension. But if you're sleeping four hours a night, eating in a way that drives systemic inflammation, and not moving at all, those variables will outweigh what the light is doing. The biology of chronic pain is multifactorial. Treat it that way.
References
Oliveira, S., et al. (2024). Effectiveness of photobiomodulation in reducing pain and disability in patients with knee osteoarthritis: a systematic review with meta-analysis. Physical Therapy, 104(8), pzae073. https://pubmed.ncbi.nlm.nih.gov/38775202/
Zhang, R., & Qu, J. (2023). The mechanisms and efficacy of photobiomodulation therapy for arthritis: a comprehensive review. International Journal of Molecular Sciences, 24(18), 14293. https://pubmed.ncbi.nlm.nih.gov/37762594/
Oschman, J.L., Chevalier, G., & Brown, R. (2015). The effects of grounding (earthing) on inflammation, the immune response, wound healing, and prevention and treatment of chronic inflammatory and autoimmune diseases. Journal of Inflammation Research, 8, 83-96. https://pmc.ncbi.nlm.nih.gov/articles/PMC4378297/
Frequently Asked Questions
Does red light therapy actually work for joint pain? The research is solid enough to take seriously. A 2024 meta-analysis of ten randomised controlled trials found photobiomodulation reduces pain and disability in knee osteoarthritis. The mechanism is well-documented through mitochondrial activation, improved blood flow via nitric oxide release, and reduction of pro-inflammatory cytokine signalling. It's not a cure, but it's a genuine biologically grounded intervention with substantially more clinical evidence behind it than most people realise.
Hjelper rødlysterapi mot leddsmerter? / Does red light therapy help with joint pain? Ja, forskning støtter bruken av fotobiomodulasjon for leddsmerter. En metaanalyse fra 2024 fant at fotobiomodulasjon reduserer smerte og funksjonshemming ved kneartrose sammenlignet med placebo. Effekten virker gjennom mitokondriell aktivering, økt blodsirkulasjon via nitrogenoksid og reduksjon av proinflammatoriske cytokiner.
What wavelength is best for joint pain? For joints and deeper muscle tissue, near-infrared around 850nm is essential. It penetrates 20 to 30mm through tissue, reaching synovial tissue, muscle belly and periosteum. Red light at 660nm is effective only for superficial tissue and doesn't reach joint structures in most cases. If you're treating a knee, hip, or shoulder, 850nm is not optional. A device that only emits red light will not do what you need it to do.
What's the difference between near-infrared and far-infrared for pain? This matters more than most people realise. Far-infrared (saunas, heat lamps) works thermally, warming tissue, which can feel good and has some benefits. It does not produce the photobiological effects on cytochrome c oxidase that drive the cellular changes I've described here. Near-infrared (600 to 1000nm range) is what photobiomodulation research is based on. They're different mechanisms. If you want the mitochondrial and anti-inflammatory effects, you need the right wavelength range, not just any infrared.
How long before near-infrared light helps with chronic pain? Acute pain: one to two weeks of consistent daily use can produce noticeable change. Chronic conditions: six to twelve weeks minimum before you have a fair assessment. People who stop at three weeks almost always do so just before results would have become obvious. Consistency over time matters far more than session length or intensity.
Why does joint pain get worse in Norwegian winter? Primarily because Norwegian winter removes red and near-infrared wavelengths from your environment for months at a time. Indoor LED lighting is spectrally impoverished. Your mitochondria depend on these wavelengths to maintain cellular energy capacity. With months of near-zero near-infrared input, inflamed tissue repairs more slowly, pain thresholds lower, and flare-ups last longer. It's not mainly the cold. It's the light.
Can I use near-infrared light alongside medical treatment for arthritis? Yes. Near-infrared light therapy addresses the cellular energy and inflammation dimension. It doesn't interfere with medications and isn't positioned as a replacement for medical management. It works alongside other approaches, including grounding for oxidative stress reduction, movement, sleep quality, and diet. The biology of chronic inflammation is multifactorial and responds better to addressing multiple variables simultaneously than to any single intervention.
See the full red light panel range or portable targeted devices. Grounding products are here. More questions? FAQ page or get in touch directly.
Les den kortere norske versjonen her: /blogs/norsk/infrarodt-lys-leddsmerter-muskelsmerter
These are general health products, not medical devices. If you have a diagnosed inflammatory condition, please work with a doctor. Near-infrared light therapy is a complementary approach, not a replacement for medical treatment.