Red Light Therapy for Tendonitis | LightTherapy.no
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Red Light Therapy for Tendonitis: What It Actually Does
I'll tell you how I know I've got the first signs of tendonitis coming on. It's that little hot spot. That one specific bit of the tendon that feels slightly off when you move in a particular way, that you can ignore for a day, maybe two, and then by day three you're going "hmm, that's not going away." For me it's usually somewhere around the knee, sometimes the shoulder, because (two very different areas, but it is all connected) I've got osteoarthritis and when the joint isn't quite doing its job the tendons around it pick up the slack. They were not designed to pick up that slack. And they let you know.
The moment I feel it, the torch comes out. I'm not waiting. I'm not seeing if it sorts itself. Because I know from experience that a tendon you catch at day three is a completely different problem from a tendon you've been limping on for six weeks.
Red light therapy (rødlysterapi) helps tendonitis by sending red and near-infrared wavelengths into the injured tendon, where they boost mitochondrial energy production in the cells that make and repair collagen, calm down the local inflammation, and pull more blood into a tissue that has hardly any blood supply to begin with. Multiple peer-reviewed studies show pain reduction and improved function when photobiomodulation is added to standard rehab, with the best results for Achilles tendinopathy, tennis elbow, and rotator cuff problems.
Why I Know This One So Well
Look, I've got osteoarthritis. Have done for years. It's part of why I went down this whole rabbit hole in the first place. And one of the things you learn pretty quickly when a joint isn't doing its job properly, is that the tendons around it start working overtime. They're holding the joint together, they're stabilising movements the cartilage used to handle quietly. So they take a beating.
Which means I get tendonitis warning signs more than the average person. And I've had to learn what works fast, because the alternative is a tendon problem that turns into a months-long thing, which then turns into me not being able to do the stuff I actually want to do, like getting out on the terrace, walking with my daughter, whatever.
So when I talk about tendonitis I'm not just talking about something I read in a paper. I'm talking about something I'm actively managing in my own body, with my own panels, with my own protocols, more or less constantly.
Why Tendons Heal So Slowly
Here's the thing nobody explains when they hand you the sheet of exercises and send you home. Tendons are not muscles. Sounds obvious, but the implication isn't.
Muscles are full of blood vessels. Pull one, blood rushes in, all the repair signalling and the cells and the oxygen turn up, and three weeks later you're fine. Tendons? Hardly any blood supply at all. You could almost count the vessels on one hand. So the cells inside the tendon, the tenocytes, the ones doing the actual repair work, they're sitting in a low-oxygen, low-nutrient environment, doing slow, quiet work.
That's why your hamstring strain is gone in a fortnight and my mate's Achilles is still bothering him nine months later. Different tissue. Different timeline. Different rules.
How long have you been dealing with yours? Because this matters. If you're inside six weeks, you're still in the window where the inflammation is the main story. After that, the tendon starts laying down disorganised collagen, the structure of the thing changes, and you're in tendinopathy territory rather than tendonitis. The biology shifts. The standard ice-and-ibuprofen logic stops applying because there isn't much inflammation to dampen anymore. The tissue is just badly built now and needs help rebuilding.
This is exactly the gap where light becomes interesting. Because most of the standard tools work on the inflammation part. Light works on the cellular environment the tendon needs to actually rebuild.
What's Actually Happening When You Put a Panel on It
Right, the mechanism. I'll try not to make this too textbook because honestly that's part of what I find annoying about how this stuff usually gets explained.
You stick the panel on the tendon. Within a few minutes, your blood vessels relax. This is the nitric oxide thing, the near-infrared wavelengths trigger the cells lining your blood vessels to release nitric oxide, which is basically the molecule that tells those vessels to open up. More blood flow. Into a tissue, remember, that normally has hardly any. You're flooding the place with oxygen and nutrients it has been chronically starved of. That alone is doing real work.
Underneath that, the mitochondria are doing their thing. Red light around 630-680nm and near-infrared around 800-850nm get absorbed by an enzyme called cytochrome c oxidase, which sits in the mitochondria. When that enzyme catches these specific wavelengths, ATP production goes up. ATP is what cells run on. Tenocytes that were operating on a starvation diet suddenly have fuel. They start making more collagen. The fibroblasts wake up. The disorganised mess of fibres slowly gets rebuilt into something that actually looks like a tendon again.
If you want the research, Tripodi and colleagues did a meta-analysis in 2021 in BMC Musculoskeletal Disorders, looking at 17 randomised controlled trials, 835 patients across various tendinopathies. They found photobiomodulation plus exercise beat exercise plus sham, with statistically significant improvements in pain and function. The paper's here.
Naterstad and colleagues did a tighter one in 2022 in BMJ Open, focused specifically on lower-extremity tendons and plantar fasciitis. Same direction, low-level laser at the right dose beats placebo for pain and function. Here on PubMed.
And for shoulders specifically, there's a 2025 systematic review in Wound Repair and Regeneration on rotator cuff pathology, showing the same pattern. Light plus exercise rehab does better than rehab alone. Linked here.
None of these reviews say this is a miracle cure. They all say study quality varies, doses vary, more work is needed. Fair enough. What they consistently show is that when the light gets into the tendon at the right dose, things improve. When it doesn't, they don't. Which brings me to the bit that actually annoys me.
The Dose Problem — Where I Get Worked Up
Right, so this is where I start ranting a bit, fair warning.
Photobiomodulation has a biphasic dose response. That's a fancy way of saying that too little light does nothing, the right amount does what we just talked about, and too much actually makes it worse. Like cooking. Oven at 100 degrees, your food's raw. Oven at 200, your food's done. Oven at 350, you've ruined dinner. Light is the same. There's a dose window. You either land in it or you don't.
And almost nobody selling red light panels in Norway talks about this. Which is, frankly, why I get so many emails from people who bought a panel somewhere else, used it diligently for three months, felt absolutely nothing, and are now wondering if the whole thing's nonsense.
Here's what happens. They message me. They tell me the brand of panel, how they've been using it, what they're trying to treat. And one of two things is going on. Either the panel is genuinely underpowered for what they're trying to do, in which case the dose at the skin is so low that nothing was ever going to happen, or the panel is fine but the protocol they were sold is generic rubbish that doesn't account for the tissue depth, the wavelength, the distance, any of it.
I help them anyway. I'll happily look at what you've got and tell you what it's probably delivering and how to adjust. You don't have to buy anything from me to get that. Just message me. Honestly. I'd rather you got results from the panel you already own than have you give up on the whole modality because someone sold you a piece of kit and didn't know what to do with it.
Sometimes we work it out, you tweak the distance and the time and you start getting somewhere. Other times we work out that the panel just isn't capable, and the person decides to get something proper. In which case I'll often suggest keeping the first one for skin or surface stuff and using the new one for the deeper tissue work. Two devices, used for different jobs, often makes a lot more sense than throwing the first one in a cupboard.
What gets me about this is the people doing the selling. They don't use the panels themselves. They don't measure them. I mean really measure them, with a spectrometer, not a solar meter that tells you whatever you want to hear. And they hand the same protocol sheet to a 65-year-old with a frozen shoulder and a 30-year-old wanting to do skin work. That's not a tool being sold. That's a box being shifted. And it costs the customer the actual outcome they came looking for.
I test every panel with a spectrometer before I'll put it on the site. I've sent panels back when the numbers didn't match what was claimed. Not fun conversations with suppliers, but if the panel I send you isn't doing what I said it would, you're going to be one of those people emailing me in three months saying nothing happened. And I'd rather have the awkward call with the manufacturer than the disappointed one with you.
If you want the longer version of why irradiance numbers are mostly fictional in this industry, I wrote about that here.
What I Actually Do When I Feel One Coming On
Let me describe the protocol I use on myself, because this is genuinely how I do it, not a theoretical thing.
The second I feel that little hot spot, that signal that says something's brewing in a tendon, I get a panel on it. Same day. Not "I'll see if it goes away" — I know from years of this that the early window is where you get the easy wins. Ten minutes, close range, on the spot that's bothering me. Then again before bed if I can. The next day, same thing.
If I catch it in those first few days, it usually backs off within a week. Sometimes within three or four days. That's not a clinical claim, that's just my pattern. And the difference between catching it then and trying to catch it three weeks later when it's properly established is enormous.
For something that's already chronic, it's a different story. You're looking at 10 to 15 minute sessions, once or twice a day, for at least 6 to 8 weeks before you can fairly judge whether it's working. Tendons heal slowly. Chronic ones heal even slower. There's no version of this where you blast it for an hour on Tuesday and feel better on Wednesday. Doesn't work like that.
And it doesn't work on its own. If your physio gave you eccentric loading exercises, do them. The light makes the cellular environment better for the tendon to rebuild in. The exercises give the tendon the mechanical signal it needs to rebuild in the right pattern. The combination beats either alone. The studies are clear about this and so is my own experience.
A Quick Honest Bit
Red light therapy isn't a magic eraser. If you've ruptured a tendon, you need a surgeon, not a panel. If your tendonitis is being caused by your desk setup or your running gait or the way you grip a racket, the light will only do so much because you're putting the damage back in faster than the light can pull it out. The light is the cellular environment. The behaviour is the load. You have to fix both.
What red light therapy is, used properly, is one of the better-tolerated tools I know of for slow-healing soft tissue. No GI side effects. No tendon-weakening like repeated cortisone. No surgical risk. For someone who's already tried the standard pathway and is still bothered months later, it's worth knowing about. And if you've got an underlying joint issue like I do, where tendons are always going to be picking up extra strain, having one in the house is a quiet bit of insurance.
If you want to chat through what would actually work for your specific situation, the tendon, your budget, what you're already using, just message me. I do this every day. You can also have a look at the red light therapy panel collection or the portable and specialist devices if you're after a smaller, targeted thing for one specific tendon.
Where Tendonitis Fits in the Bigger Picture
If you've read the knee pain post, you'll notice the biology overlaps a lot. Cartilage and tendons share the slow-healing, low-blood-supply problem. Both respond to better circulation, calmer inflammation, more cellular energy. Which is partly why if you're someone like me, with an underlying joint problem driving the tendon issues, treating both at once tends to work better than treating just the tendon and ignoring the joint underneath.
The 2025 half-year research review covers the wider picture, muscle recovery, joint disease, all of it. Same pattern keeps showing up. Right dose, consistent use, slow-healing tissues do better.
Disclaimer: This article is for educational purposes only. It's not medical advice. If you've got a tendon injury or suspected tendonitis, talk to a qualified healthcare professional before starting any new therapy. Red light therapy is not a substitute for proper diagnosis, rehabilitation, or surgery where these are needed.
Norwegian version of this article: https://lighttherapy.no/blogs/norsk/rodlysterapi-mot-senebetennelse
Frequently Asked Questions
Does red light therapy actually work for tendonitis?
Yes, the evidence supports it as a useful add-on treatment, particularly when combined with the exercise rehab a physio would prescribe. Multiple systematic reviews show pain reduction and functional improvement compared to placebo, with the strongest results for Achilles tendinopathy, tennis elbow, and rotator cuff problems. The effect is real but moderate. Results depend heavily on getting the dose right, which is where most people who try this and feel nothing have gone wrong. It works best as part of a wider plan, not on its own.
How long does it take for red light therapy to help tendonitis?
If you catch it early, within the first week or two of symptoms, you can often see things settle within a few weeks of daily sessions. For chronic tendinopathy that's been there for months, expect to commit to at least 6 to 8 weeks of consistent daily use before judging whether it's working. The tissue is slow-healing regardless of what you throw at it, so patience matters more than session intensity. Blasting it for longer doesn't help, and can actually hurt because of the biphasic dose response.
Which wavelengths are best for tendonitis?
Both red light around 630-680nm and near-infrared around 800-850nm have been studied for tendon repair. Near-infrared penetrates deeper into tissue, which matters for deep tendons like the Achilles, patellar, or rotator cuff. Red light works fine on superficial tendons like the lateral epicondyle in tennis elbow. Most decent panels combine both, which is what I'd default to if you weren't sure exactly which tendons you'd end up treating.
Kan rødlysterapi hjelpe mot betennelse i akillessenen?
Ja, det er solid dokumentasjon på at rødlysterapi kan redusere smerte og forbedre funksjon ved akillestendinopati, særlig kombinert med eksentriske øvelser. Behandlingen øker blodsirkulasjonen i et vev som naturlig har dårlig blodtilførsel, demper lokal betennelse, og gir tenocyttene mer energi til å bygge om skadet kollagen. Du må regne med daglig bruk i minst 6 til 8 uker for å se reell forbedring på en kronisk senebetennelse. Akutte tilfeller responderer ofte raskere hvis du tar dem tidlig.
Can I use red light therapy alongside cortisone or ibuprofen?
Generally yes, with some caveats. Cortisone works over weeks and there's no obvious interaction with adding light therapy. Ibuprofen and other NSAIDs dampen some of the inflammatory signalling that's also part of the early healing process, which is why their long-term role in tendon repair is increasingly questioned by researchers. Many people find they can reduce their NSAID use as the light therapy starts to help. If you're on prescribed medication, talk to the doctor who prescribed it before changing anything.
References
Tripodi N, Feehan J, Husaric M, Sidiroglou F, Apostolopoulos V. The effect of low-level red and near-infrared photobiomodulation on pain and function in tendinopathy: a systematic review and meta-analysis of randomized control trials. BMC Musculoskeletal Disorders. 2021. https://pmc.ncbi.nlm.nih.gov/articles/PMC8364035/
Naterstad IF, Joensen J, Bjordal JM, Couppé C, Lopes-Martins RAB, Stausholm MB. Efficacy of low-level laser therapy in patients with lower extremity tendinopathy or plantar fasciitis: systematic review and meta-analysis of randomised controlled trials. BMJ Open. 2022. https://pubmed.ncbi.nlm.nih.gov/35418423/
Effectiveness of Photobiomodulation and Exercise-Based Rehabilitation on Pain and Functional Recovery in Patients With Rotator Cuff Pathology. Wound Repair and Regeneration. 2025. https://pmc.ncbi.nlm.nih.gov/articles/PMC12079619/
Cotler HB, Chow RT, Hamblin MR, Carroll J. The use of low-level laser therapy (LLLT) for musculoskeletal pain. Journal of Photochemistry and Photobiology B: Biology. 2015. https://pubmed.ncbi.nlm.nih.gov/26858986/