Pulsed Red Light Therapy: What the Research Says

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Pulsed Red Light Therapy: What the Research Actually Says (and What I Personally Notice)

Last autumn I did a long hike up in the hills behind Drammen. Nothing crazy, but enough that my ankle , the one with osteoarthritis, the one I write about a lot, was sore by the time I got home. I put the PulseWave Pro on it that evening with the pulsing on. Sat on the terrasse with a coffee, ankle warming up, calf next.

Did it help? I think so. Maybe. By the morning I felt better than I usually would after that kind of day. But here's the thing, I can't tell you with certainty whether it was the pulsing or just the light. And that's basically where the whole pulsed PBM conversation sits right now. There's real research. There's also a lot of marketing nonsense. I want to walk you through both, honestly, because nobody else selling these panels in Norway is talking about this at all.

Quick answer

Pulsed red light therapy means delivering the light in rapid on-off cycles at specific frequencies (10 Hz, 40 Hz, 100 Hz, etc.) instead of as a constant beam. A growing body of research  (including the Hashmi review in 2010 and the Kim group's 2017 work on mitochondrial bioenergetics) suggests pulsed mode can outperform continuous mode for some applications, with the optimal frequency depending on what you're trying to do. The MIT gamma research at 40 Hz is the most exciting piece of the puzzle, though it's been done with sensory flicker rather than transcranial PBM. The honest summary is: the science is real, it's emerging, and not yet definitive. Pulsing is worth having available, but it's not a magic switch.

Why I'm even mentioning this

Have a look around. The other Norwegian red light retailers - and there are a few decent ones now - don't talk about pulsing in any depth. Their product pages mention it as a feature if it exists. Sometimes they list a frequency. That's about it. No explanation of what it does, why it might matter, where the research stands.

I find this strange. The PulseWave Pro has multiple pulse frequencies. People are paying extra for them. The least I can do is explain what they actually are and what the evidence looks like. So that's what this post is.

I'm not going to oversell it. I'm not going to tell you pulsed light cures Alzheimer's or that 10 Hz is the "healing frequency." Some of the marketing copy you'll read online does exactly that, and it's embarrassing. But there's a real story here too, and you deserve to hear both sides before you decide whether pulsing matters to you.

What "pulsed" actually means

A red light therapy panel in continuous mode does what it sounds like - the LEDs are on, steadily, for however long your session lasts. Energy flows in at a constant rate.

In pulsed mode, the LEDs are switching on and off rapidly, dozens or hundreds of times per second. The pulse frequency is how often this on-off cycle happens. 10 Hz means ten cycles per second. 40 Hz, forty. Your eye doesn't usually see the flicker because it's faster than your visual system processes, though sometimes at lower frequencies you'll notice a slight strobe.

The total amount of energy delivered over a session can be the same as in continuous mode. The difference is in the pattern of delivery, and the question researchers have been chewing on for over a decade is whether that pattern matters for the biology.

The research, honestly

Right, so here's where it gets interesting.

In 2010, James Hashmi and a team that included Michael Hamblin (one of the most cited researchers in the field) published a comprehensive review in Lasers in Surgery and Medicine titled "Effect of pulsing in low-level light therapy." They went through dozens of studies. Their conclusion was cautious but clear,  in many biological systems, pulsed delivery appeared to outperform continuous, but the optimal frequency varied wildly depending on what was being treated, and the mechanisms weren't well understood.

Then in 2017, a Korean group published a paper in Scientific Reports on human dental pulp stem cells. They used 810 nm light at the same total energy and compared continuous to pulsed at different frequencies. They found that 30 Hz and 300 Hz produced the strongest effects on mitochondrial activity, while 3 Hz did almost nothing. Same total energy. Same wavelength. Different biology depending on the pulse rate.

The Keshri group did similar work on wound healing in rats. Pulsed near-infrared at 810 nm gave better dermal wound healing than continuous in their immunosuppressed model.

So at the cellular level, the case for pulsing being more than just marketing is actually decent. Something real is happening when you change the pulse frequency, even at the same energy dose.

Then there's the gamma stuff

This is the part that gets people excited, and I want to be careful here.

At MIT, Li-Huei Tsai's lab has been publishing for nearly a decade now on what they call GENUS - gamma entrainment using sensory stimuli. They flash light at 40 Hz at mice, and at humans. In mouse models of Alzheimer's, this 40 Hz sensory flicker reduced amyloid plaques, reduced tau pathology, preserved synapses, and improved memory. The 2016 Nature paper was a landmark. There have been follow-ups in Nature, Cell, and elsewhere ever since.

Phase 3 human trials are now running through a company called Cognito Therapeutics. Small early-stage human studies, published in PLOS ONE in 2022, suggested the approach is safe and might be associated with neurological benefits.

Now — here's the honest part. This research is mostly done with visual 40 Hz flicker (and audio clicks). The mechanism is sensory entrainment of brain rhythms. It is not identical to shining a 40 Hz pulsed red light panel on your forehead. The two might overlap, transcranial PBM at 40 Hz is being studied,  but you should not read the MIT gamma research as "if I use 40 Hz on my head I get the same effect." The evidence for transcranial pulsed PBM at 40 Hz specifically is much thinner and earlier-stage.

I mention this because I see a lot of red light vendors quote MIT's gamma research as if it directly validates their 40 Hz panel setting. It doesn't. What it does is establish that 40 Hz neural stimulation matters biologically, which makes pulsed PBM at that frequency genuinely worth studying, and worth trying, carefully, on yourself if you want.

What I personally do

I use pulsing mostly on my head, and mostly with my other units (smaller, more targeted devices designed for transcranial use). I usually run 10 Hz or 40 Hz. 10 Hz is in the alpha range, which is associated with relaxed alertness. 40 Hz is the gamma band the MIT work is built around. Whether shining red light at my forehead at these frequencies entrains anything meaningful, honestly, I don't know. Sometimes I feel sharper afterwards. Sometimes I don't notice anything. I keep doing it because the downside is zero and the upside might be real.

On the body;  the ankle, the calf after hiking,  I've used the PulseWave Pro's pulsing too. As I said up top, I think it helped. But I also use continuous mode on those areas plenty, and continuous works fine. By the way, I tend to default to continuous for serious soreness or recovery work because I'm more confident in the dose I'm delivering. Pulsed feels like the extra option I reach for when I want to experiment, or for the head.

That's the honest position. I'm not going to pretend I have certainty I don't have.

The dose problem (again)

You'll notice I write about irradiance and dose in nearly every post on this blog. It applies here too. A panel that delivers 25 mW/cm² in continuous mode is delivering less average power in pulsed mode at, say, 50% duty cycle - because half the time the LEDs are off. This matters. The total energy over a session changes. Some pulsed setups compensate by running longer; some don't.

If your panel has a pulse function, the questions to ask are: what frequencies, what duty cycle, and does the manufacturer disclose what the actual delivered irradiance is in pulsed mode versus continuous. Most don't. We do - and if you bought a panel elsewhere and want to figure out what you're actually getting, send me a photo of the spec sheet and I'll help. No obligation. I just find this stuff genuinely interesting and most Norwegian buyers are being underserved on the technical side.

What I'd actually tell a friend

If you're new to red light therapy, ignore pulsing for now. Buy a good panel with strong continuous irradiance and proper wavelength balance, use it consistently for a few months, and see what changes for you. Pulsing is a refinement, not a foundation. You can't pulse your way out of a weak panel.

If you've been using red light for a while and you have a device with pulse options, here's roughly how I'd play it. Use continuous for skin, collagen, general body work, post-workout recovery. Try pulsed for transcranial (head) work if your device supports it - 10 Hz or 40 Hz if you have to pick. Try pulsed for stubborn joint pain that hasn't responded to continuous, just to see if your body responds differently. Keep notes. Treat yourself as a single-subject experiment, not a clinical trial.

And if you ever read a marketing claim that says "300 Hz is the optimal frequency for cellular ATP production" or "1000 Hz is for deep tissue healing" stated with confidence,  be sceptical. The research doesn't actually support that level of precision yet. The Companion Animal Health veterinary group (which sells laser therapy equipment) bluntly wrote that "manufacturers have made elaborate claims about specific pulsing protocols" that are "more marketing hype than science." That's a vendor saying it about other vendors. I think they're right.

Where pulsing actually shines (so far)

If I had to summarise where the research is strongest:

In the lab - on cell cultures and animal models - pulsed PBM does often outperform continuous at certain frequencies. The mitochondrial work from Kim and colleagues is the cleanest example. Different pulse rates produce measurably different biological responses at the same total energy.

For wound healing - there's animal model evidence (Keshri, Mosca, and others) that pulsed delivery can improve outcomes versus continuous.

For brain applications - the MIT gamma research is the strongest signal that 40 Hz neural stimulation does real things, even though the application to transcranial PBM specifically is still early.

For everyday human use on your body - the honest answer is the differences between pulsed and continuous probably matter less than getting your panel, wavelengths, dose, and consistency right. Pulsing is an interesting refinement. It is not the main lever.

That's where I'm at. I'll keep reading the research. I'll keep trying things on my own ankle and head. If anything changes my view I'll write an update.

A note on what we actually sell

The PulseWave Pro is the only panel in our lineup with built-in multi-frequency pulsing. It runs continuous as well, so if you're not sure whether you'd use pulsing, you can buy it and just leave the pulse off until you want to try it. Our other panels,  the BioWave Core models are continuous-only, which is fine. Continuous is what 95% of the research is built on. You don't need pulsing to get strong results.

If you want to read more about the underlying engineering -  what makes a panel actually deliver what it claims, why the wavelength split matters, how to measure real irradiance, start here on irradiance and here on the 2025 research review. For muscle recovery applications where pulsing might matter, that post covers continuous-mode use which is still the better-evidenced approach.

You can see the full panel range on the collections page. If you want to ask me anything before buying, or if you bought elsewhere and want a second opinion on what you have, drop me a message. I'm in Drammen and I answer my own emails.

FAQ

Is 40 Hz pulsed red light the same as the MIT gamma research? No - and this is important. The MIT research at Tsai's lab uses 40 Hz visual flicker (and audio clicks) to entrain brain rhythms. Transcranial PBM at 40 Hz might overlap with this mechanism, but the evidence is much earlier and thinner. Don't buy a pulsed panel expecting it to replicate the Alzheimer's research findings.

Hva er forskjellen på pulsert og kontinuerlig rødlysterapi? Kontinuerlig betyr at LED-ene lyser jevnt under hele økten. Pulsert betyr at de slår seg av og på raskt, mange ganger i sekundet, ved en bestemt frekvens. Total energi kan være lik, men leveringsmønsteret er forskjellig — og forskning antyder at biologien noen ganger reagerer ulikt på de to modusene.

Which pulse frequency should I use? Honest answer: nobody knows for sure yet. If I had to pick defaults, I'd say 10 Hz for relaxation and general work, 40 Hz for cognitive or head applications, and continuous for everything else until you have a reason to experiment. The optimal frequency almost certainly depends on what tissue you're treating and what outcome you want, and the research hasn't pinned that down.

Will pulsing reduce my dose? It can, depending on the duty cycle. If the LEDs are on 50% of the time during a pulsed session, you're getting roughly half the average irradiance compared to continuous. Some sessions you compensate by going longer. This is something most manufacturers don't tell you clearly. Ask before you buy.

Is pulsed light safer than continuous? Safety isn't really the differentiator, both modes are well-tolerated at therapeutic doses. Pulsing tends to produce slightly less tissue heating, which is occasionally cited as a benefit for sensitive areas, but red light at normal panel doses doesn't produce much heating anyway.

Disclaimer

This post is for educational purposes only. It is not medical advice. Photobiomodulation including pulsed delivery is not a treatment for any specific disease, and you should consult your physician before using red light therapy if you have a medical condition, are pregnant, or take medications that affect light sensitivity. The research described here is summarised in good faith but is still emerging, and individual responses vary.

References

• Hashmi JT, Huang YY, Sharma SK, Kurup DB, De Taboada L, Carroll JD, Hamblin MR. Effect of pulsing in low-level light therapy. Lasers in Surgery and Medicine 2010;42(6):450-466.
• Kim HB, Baik KY, Choung PH, Chung JH. Pulse frequency dependency of photobiomodulation on the bioenergetic functions of human dental pulp stem cells. Scientific Reports 2017;7:15927.
• Keshri GK, Gupta A, Yadav A, Sharma SK, Singh SB. Photobiomodulation with pulsed and continuous wave near-infrared laser (810 nm, Al-Ga-As) augments dermal wound healing in immunosuppressed rats. PLoS One 2016;11(11):e0166705.
• Iaccarino HF, Singer AC, Martorell AJ, et al. Gamma frequency entrainment attenuates amyloid load and modifies microglia. Nature 2016;540(7632):230-235.
• Chan D, Suk HJ, Jackson BL, et al. Gamma frequency sensory stimulation in mild probable Alzheimer's dementia patients: Results of feasibility and pilot studies. PLOS ONE 2022;17(12):e0278412.
• Ilic S, Leichliter S, Streeter J, Oron A, DeTaboada L, Oron U. Effects of power densities, continuous and pulse frequencies, and number of sessions of low-level laser therapy on intact rat brain. Photomedicine and Laser Surgery 2006;24(4):458-466.
• Saltmarche AE, Naeser MA, Ho KF, Hamblin MR, Lim L. Significant improvement in cognition in mild to moderately severe dementia cases treated with transcranial plus intranasal photobiomodulation: Case series report. Photomedicine and Laser Surgery 2017;35(8):432-441.