Photobiomodulation Research: April 20th 2026
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Photobiomodulation Research: What Landed This Week
Published 20 April 2026 | Dominic Lamb
Quick Answer: This week's photobiomodulation research covers near-infrared light for insomnia in older adults, age-related macular degeneration, chronic pain, heart rate recovery, and the largest-ever clinical consensus on how to actually use PBM safely. The sleep study in particular is one worth reading closely - it tested 850 nm light applied to the neck at night and found real changes in both sleep quality and melatonin timing.
Here is something I keep coming back to: most people who ask me about red light therapy (rødlysterapi) are already dealing with something. Knee pain that won't shift. Eyes getting worse. Sleep that hasn't been right in years. They are not abstract wellness researchers. They want to know if this stuff actually helps them specifically.
So that is how I try to read each week's research. Not "is photobiomodulation (fotobiomodulasjon) a real thing" - that question has been answered, repeatedly, by now. But rather: does this paper tell me something useful about a real problem real people have?
This week the answer is yes, several times over.
What Is Photobiomodulation and How Does It Work?
Short version for anyone new here: photobiomodulation is the use of red and near-infrared light (nærinfrarødt lys) in the 600 nm to 1000 nm range to trigger biological responses in tissue. The light is absorbed primarily by cytochrome c oxidase, the terminal enzyme in the mitochondrial electron transport chain. When that enzyme absorbs photons, it produces more ATP (cellular energy), releases nitric oxide, and modulates how cells handle oxidative stress.
The effect is not heat. It is photochemical. The light is a signal, not a stove.
Dr. Michael Hamblin at Harvard has spent decades mapping this. Dr. Alexander Wunsch, whose work I have referenced on here before, has looked at the broader spectral requirements for healthy biology, including why certain wavelengths matter more than others for specific tissues. The field is real. The dosing questions are still being worked out, which is why the consensus paper this week is actually important news.
Near-Infrared Light for Sleep and Melatonin in Older Adults
This is the one I want to start with because it is directly relevant to a lot of people for us in Norway, where mørketid does real damage to sleep patterns over winter and the recovery into spring is not always straightforward.
Researchers in Taiwan ran a randomised clinical trial with 59 adults aged 60 and over, all experiencing early waking or sleep-maintenance insomnia. They split participants into three groups: near-infrared light alone (850 nm applied to the neck), white bright light alone, and a combination of both. Treatment was 60 minutes nightly over two weeks.
The near-infrared group showed improvements in sleep quality. What is interesting is the mechanism. Applying 850 nm light to the neck targets a cluster of blood vessels and nerve tissue near the surface. The researchers were essentially looking at whether photobiomodulation could shift melatonin timing without the brightness-dependent pathway that white light uses. Melatonin, as Dr. Russel Reiter's work has shown for years, is far more than a sleep hormone. It is a potent mitochondrial antioxidant, and its timing matters as much as its quantity.
The combined group did best overall. But the fact that NIR alone produced meaningful changes is significant, because it suggests a pathway that does not depend on exposing ageing eyes to bright light at night.
This is a randomised controlled trial, which is a good level of evidence. The sample size is modest at 59 participants, and it was conducted in Taiwan, so applying it directly to Norwegian older adults means accounting for differences in baseline light environment. But the direction of effect is clear enough to take seriously.
(Chen et al., Photodiagnosis and Photodynamic Therapy, Read the study)
Can Red Light Therapy Help With Age-Related Macular Degeneration?
Straight answer: there is now real clinical evidence that it can slow some of the damage, at least in the intermediate stage of the disease.
A retrospective pilot study from 2026 followed 60 patients - 30 receiving PBM treatment and 30 age-matched controls. The treatment group used the EYE-LIGHT device for eight sessions over four weeks. At two months, the PBM group showed improved best-corrected visual acuity, reduced drusen volume (drusen are the protein deposits that accumulate under the retina in AMD), and improved blood flow in the choriocapillaris, the tiny capillary network that feeds the retina.
This matters a great deal. AMD is the leading cause of vision loss in people over 65 in wealthy countries. There is currently no effective treatment for the dry intermediate form of the disease, which is what most patients have before it progresses to the wet form. These findings, small and preliminary as they are, suggest that light may be doing something at exactly the tissue level where the disease causes its damage.
Prof. Glen Jeffery at University College London has been working on this for years. His earlier work showed that 670 nm light applied to the eyes in older adults improved colour discrimination and contrast sensitivity. The biology is consistent: the retina is metabolically extremely demanding, and mitochondrial function declines with age first in the photoreceptors. PBM appears to top up that mitochondrial function before irreversible structural damage sets in.
This is a pilot study, retrospective in design, which means it is hypothesis-generating rather than definitive. But the signal is consistent with earlier work, and the mechanism makes biological sense.
(Toto et al., Eye, Read the study)
The Official Clinical Consensus Has Arrived
This deserves its own section because it is a different kind of paper. Not a single trial. A formal consensus document from the Journal of the American Academy of Dermatology, produced by 21 specialists after a systematic literature review, two rounds of Delphi survey, and two consensus meetings.
What they concluded is that PBM is safe for adult patients, that red light PBM does not cause DNA damage, and that there are now enough consistent findings to produce clinical recommendations for its use in specific conditions. The list of included applications spans wound healing (sårheling), musculoskeletal pain (smertelindring), hair loss, radiation dermatitis, pressure ulcers, peripheral neuropathy, sports performance, stroke rehabilitation, and cognitive support.
What this means practically: PBM is no longer sitting in the "interesting but unproven" drawer as far as the American dermatology establishment is concerned. This is a formal guideline. That is a meaningful shift.
I will be honest about the limitations: the systematic review covered literature up to June 2022, so some of the more recent neurological work is not fully reflected. And the guidelines are framed around clinical settings with calibrated devices, not consumer panels. I will come back to that in the honest picture section below.
(Siegel et al., Journal of the American Academy of Dermatology, Read the study)
Photobiomodulation for Chronic Pain: A New Systematic Review
A 2026 systematic review published in Frontiers in Integrative Neuroscience pulled together randomised controlled trials on PBM and chronic pain conditions: fibromyalgia, headache, temporomandibular disorders, neuropathic pain, neck pain, orofacial pain. The search covered a decade of published work.
The overall finding was that PBM shows consistent analgesic and functional improvement across these conditions, with a good safety profile. The honest caveat the authors flag themselves: protocols vary widely between studies. Wavelength, energy density, treatment duration, and frequency all differ. That makes it difficult to say "here is the dose that works."
For us in Norway dealing with chronic conditions, this is the key frustration. The evidence that light reduces pain is solid. The evidence that a specific consumer device at a specific distance for a specific duration does what a calibrated clinical laser does - that is the gap. It does not mean home devices are useless. It means they are under-researched compared to clinical equipment.
Fibromyalgia is one of the areas with the best evidence here. The umbrella review published in Springer's Systematic Reviews journal - which pooled data from over 9,000 patients across 15 different conditions - found moderate certainty evidence for fibromyalgia fatigue reduction, with an effect size that would be considered clinically meaningful. If you or someone you know has fibromyalgia and has not heard of PBM as an adjunct to other treatment, this is a conversation worth having with a doctor.
(Ferreira et al., Frontiers in Integrative Neuroscience, Read the study)
(Kuszewski et al., Systematic Reviews, Read the umbrella review)
PBM, the Vagus Nerve, and Heart Rate Recovery After Exercise
This one is more niche but genuinely interesting if you do any training or care about cardiovascular health. Brazilian researchers ran a randomised controlled trial looking at whether PBM applied to the vagus nerve (in the infra-auricular region - basically just below the ear) changes cardiac autonomic function during and after resistance exercise.
34 participants, crossover design, active PBM versus sham. They were looking at heart rate variability, which is a marker of how well your autonomic nervous system modulates cardiac function. Poor HRV recovery after exercise is associated with worse overall cardiovascular health.
The results showed that targeted vagal PBM affected cardiac autonomic modulation. I want to be careful about overselling what that means in practice, because acute effects on HRV do not automatically translate to long-term cardiovascular benefit. But the fact that photobiomodulation applied to a specific peripheral nerve location is having measurable effects on the autonomic nervous system is genuinely interesting. The vagus nerve is not some obscure structure, it is involved in inflammation regulation, gut-brain signalling, and stress response, among other things. Research on PBM's interactions with the nervous system is one of the more exciting edges of the field right now.
(Pereira et al., Journal of Biophotonics, Read the study)
Light Applied to the Blood: Systemic Effects on HDL and Insulin
A Brazilian study looked at what happens when you apply PBM transcutaneously over the radial artery (at the wrist, essentially) using different wavelengths and doses. 56 female volunteers, different protocol groups. The investigators were measuring whether light delivered over a major blood vessel could produce systemic biochemical changes.
Results: one group showed a significant increase in HDL cholesterol. Another showed a significant reduction in insulin levels. Ferritin was significantly reduced in the LED group.
I will be honest: this study is interesting but needs replication badly. The sample is small, the groups were divided into multiple sub-protocols which limits the power of any individual finding, and the clinical significance of these specific biomarker shifts needs to be tested over longer time frames. What it does show is that transcutaneous blood photobiomodulation can have systemic metabolic effects, which is consistent with the theoretical framework and with older intravenous PBM research. This is not a paper I would use to make strong claims. But it is a direction worth watching.
(Lizarelli et al., Journal of Biophotonics, Read the study)
PBM for Eye Health: A Broader Ophthalmology Review
Beyond the AMD study above, a comprehensive review published in 2024-2025 on PBM in ophthalmology (øyehelse) surveyed the evidence for corneal wound healing, retinal disease, and inflammatory eye conditions. The review connects the mitochondrial mechanism to retinal function in a way that is worth understanding.
The retina is one of the highest energy-consuming tissues in the entire body relative to its size. The photoreceptors are packed with mitochondria. They are running at essentially maximum metabolic capacity all the time. As we age, or as metabolic stress accumulates, that capacity declines, and visual function follows. The logic of using targeted light to restore mitochondrial function in retinal tissue is not speculative. It is mechanistically consistent with everything we know about how cytochrome c oxidase works.
The review covers dry eye syndrome (where PBM applied to the eyelid area via devices like the EYE-LIGHT has shown good clinical results), and emerging work on glaucoma and diabetic retinopathy. As Prof. Glen Jeffery and Scott Zimmerman have both noted in different contexts, the eye is not just a lens system. It is a photoreceptive organ across multiple wavelengths, and how we light our environments affects retinal health in ways we are only beginning to understand properly.
(Comprehensive Ophthalmology Review, PubMed, Read the study)
The Honest Picture
Every time I do one of these round-ups I include this section because I think it matters. Not as a legal disclaimer. As an honest assessment from someone who has been in this space since 2018 and has bought and tested a lot of devices.
The clinical evidence for photobiomodulation is real and growing fast. The formal consensus from the American Academy of Dermatology this week is a marker of how far the field has moved from fringe to mainstream clinical interest. For wound healing, musculoskeletal pain, oral health, and certain neurological applications, the evidence is now substantial.
Where it gets murky: dosing. Every single paper in this week's selection uses calibrated clinical equipment with known output parameters. Most consumer red light panels, including some expensive ones, have been measured by independent sources and found to deliver significantly less power than claimed, or at wavelengths that drift from what is advertised. I test devices with a spectrometer before I sell them, and I have returned units that did not match specification. This is not theoretical concern. It is something I have directly observed.
None of that means home devices are useless. Many of them work, particularly for surface applications like skin, wound healing, and joint areas with good surface access. But the claim that a 200 mW/cm2 consumer panel is equivalent to the 50 mW/cm2 clinical device used in these trials is not supported by either the physics or the literature. More is not automatically better - the dose-response relationship in PBM is biphasic, meaning you can also get too much and see diminished returns.
Buy from someone who can show you measured output data for the specific unit you are buying. Ask the question. If they cannot answer it, that is your answer.
Frequently Asked Questions
Is red light therapy (rødlysterapi) backed by real science? Yes. As of 2026, there are thousands of peer-reviewed studies and a formal clinical practice guideline from the American Academy of Dermatology. The evidence is strongest for wound healing, pain, and certain dental applications. For neurological and eye applications, the evidence is earlier-stage but biologically credible and accumulating quickly.
Can near-infrared light (nærinfrarødt lys) improve sleep? The research is emerging but promising. A 2026 randomised trial found that 850 nm light applied to the neck at night improved sleep quality and melatonin secretion in older adults with insomnia. The mechanism is different from bright light therapy and does not require the light to enter the eyes, which is relevant for people with light sensitivity or photophobia at night.
Does photobiomodulation (fotobiomodulasjon) help with eye conditions? For intermediate age-related macular degeneration (AMD), a 2026 pilot study showed improved visual acuity, reduced drusen deposits, and better retinal blood flow after a short course of treatment. Prof. Glen Jeffery's earlier work on 670 nm light and age-related visual decline supports the mechanism. These are not definitive findings, but the signal is consistent and the treatment is non-invasive.
What conditions have the most evidence for light therapy (lysbehandling)? Wound healing (particularly chronic wounds and diabetic ulcers), musculoskeletal pain, fibromyalgia fatigue, hair loss, and oral health applications have the most robust evidence base. Neurological applications including Parkinson's disease and cognitive support are the most exciting frontier, with meaningful early clinical trials now completed.
How do I know if a home red light device is actually working? You cannot know without measurement. The only reliable approach is to buy from a seller who tests output with calibrated equipment and can provide actual measured irradiance data for your specific unit. Specification claims from manufacturers are not always accurate.
There is a version of this field that will sort itself out in the next few years. The dosing questions will get answered. Standardised protocols will emerge. The gap between clinical and consumer evidence will narrow. For now, the most useful thing you can do is stay informed, buy carefully, and treat the marketing claims of any specific device with healthy scepticism - including mine (yes, everything that you read and consume should be treated equally and hopefully you become informed and empowered. But it let it inspire you to do more research, not less so you can make the best choice).
If you are looking at panels for home use, the collections I stock at LightTherapy.no are devices I have personally tested. For portable options targeting specific areas, the portable device collection is worth a look. And if sleep and circadian biology is where your head is at: the circadian and sleep lighting range is where I would start.
Disclaimer: Nothing in this post constitutes medical advice. Photobiomodulation is a research area with growing clinical evidence, but individual results vary and it should not replace treatment recommended by your doctor. If you have a specific medical condition, speak to a qualified healthcare professional before starting any light therapy protocol.