Melatonin vs Red Light for Deep Sleep
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Melatonin vs Red Light for Deep Sleep
Red light therapy (fotobiomodulasjon) and environmental red light are two different things, and it's important to understand both. Therapeutic red light panels work at the cellular level through the mitochondria. Environmental red light simply avoids switching off your body's own melatonin production in the evening. Both support better sleep, but through completely different mechanisms, and neither is the same as taking a melatonin supplement. For most people, especially for us in Norway during mørketid, using both alongside real light contrast through the day will do far more for sleep quality than any pill.
There is a question I see framed wrong almost every single time it comes up. People ask: "Should I take melatonin or use red light therapy for sleep?" And I get why it's asked that way. The supplement industry has spent a lot of money making melatonin feel like the obvious, natural, safe answer. But the question itself contains a confusion worth unpacking, because "red light" actually means two completely different things depending on how you're using it, and mixing them up means you might be leaving one of the best tools on the table without even knowing.
Let me sort that out properly, because it changes the answer significantly.
Two Types of Red Light: Not the Same Thing
This is the part most blogs skip, and it frustrates me.
When I talk about a red light therapy panel (rødlysterapi), I mean a dedicated photobiomodulation (PBM) device. A panel, a torch, a wrap. It delivers specific wavelengths in the 600nm to 850nm range at a meaningful power density, and it's designed to interact with chromophores inside your cells, primarily cytochrome c oxidase in the mitochondria. This is a therapeutic intervention. You use it for a session, typically 10 to 30 minutes. The effects happen at the cellular level. It's not really about what your eyes see. It's about what your tissues absorb.
Environmental red light is a different animal entirely. This is about the light in the room around you during the evening. A dim red bulb. A salt lamp. A candle. The warm amber setting on your circadian lighting. The idea here is simple. Your intrinsically photosensitive retinal ganglion cells (ipRGCs), the ones containing melanopsin, are what trigger melatonin suppression when light hits them. These cells are highly sensitive to short-wavelength blue and green light, peaking around 480nm, and relatively insensitive to red and amber wavelengths. So surrounding yourself with red and amber light in the two to three hours before bed avoids firing those receptors the way white LED lighting or a backlit screen does. You're not stimulating the melatonin-suppressing pathway. You're essentially letting the body proceed as if it's dark.
Both of these matter for sleep. But they work through completely different mechanisms. Conflating them is like saying "exercise" when you mean both a gentle evening walk and a 45-minute session in the gym. Related category, very different effect.
What Melatonin Supplements Actually Do (and Don't)
Before getting into how both types of red light support sleep, it's worth being clear about where melatonin supplements sit in this picture.
Dr. Russel Reiter, who has spent decades specifically on melatonin research, has documented compellingly that melatonin is one of the most powerful antioxidants the body produces, with a protective role in mitochondrial function that goes far beyond sleep signalling. That research is real and worth taking seriously.
But here's the practical reality. When you take an exogenous melatonin supplement, you're delivering a hormonal signal that should, under the right conditions, be arriving from your own body at the right time. The problem is that most people reaching for supplements are doing so because their light environment is so disrupted, all day and into the evening, that the signal was never going to arrive cleanly in the first place. You're patching over a broken system rather than fixing it. A bit like putting a plaster over a leak in the roof and calling the job done.
There's also the dosing issue. Exogenous melatonin has a short half-life and gives you a surge that's then processed and gone. Higher doses, the 5mg to 10mg formulations common in supplements you can order from iHerb or European pharmacies, are pharmacological doses that can suppress your body's own receptor sensitivity over time. The research points to 0.5mg to 1mg as closer to what the body naturally produces. At low doses, timed correctly, melatonin can genuinely help reset a disrupted rhythm or manage jet lag. As a nightly fix against a background of chaotic light exposure? It doesn't fix the underlying problem.
How Photobiomodulation (PBM) Supports Sleep
Now to the therapeutic side, and why this is about more than relaxation.
In 2007, Yeager et al. published a paper in Medical Hypotheses proposing melatonin as a principal component of red light therapy. They noted the biochemical overlap between what therapeutic red light stimulates (cytochrome c oxidase activity, glutathione redox balance, mitochondrial energy production) and what melatonin mediates in the body. Their hypothesis was that melatonin may be a downstream mediator of some of red light's broader therapeutic effects. That's a meaningful proposal, and it's held up reasonably well since.
Then in 2012, a cohort study by Zhao et al. at the China Institute of Sport Science put this more directly to the test. Twenty elite female basketball players were divided into a red light treatment group receiving 30 minutes of whole-body red light irradiation nightly for 14 days, and a placebo group. The treatment group showed significant improvements in Pittsburgh Sleep Quality Index (PSQI) scores and, importantly, significantly higher serum melatonin levels at post-intervention compared to the placebo group. The correlation between melatonin changes and sleep quality improvement was r = -0.695 (p = .006). This is currently the most directly relevant human study we have on red light therapy, melatonin, and sleep quality together.
So what's mechanistically happening? The mitochondria shift into more efficient energy production when stimulated with photons in this range. Cellular oxidative stress reduces. The cortisol pathway is less activated. Nitric oxide signalling improves local circulation. The whole cellular environment becomes less stressed, and a less stressed cellular environment creates the biological conditions for a body that can actually wind down.
I'll be honest about the limitations. Zhao et al. is a cohort study of twenty people in a specific athletic population. It's promising, not definitive, and I'd be doing you a disservice by claiming otherwise. But it's biologically coherent, the researchers have a clear proposed mechanism, and the results have been replicated in the broader pattern of what we know about PBM. Anyone telling you it's a proven cure for insomnia for all people is overstating things. What I'll say is that it's a meaningful intervention with a growing body of support.
A note on near-infrared and melatonin specifically. Scott Zimmerman's work on near-infrared light penetrating deeper tissues, including potentially the brain, raises the interesting possibility of stimulating melatonin production in the mitochondria themselves rather than exclusively through the pineal gland. This would be melatonin produced inside the cells where it's needed as an antioxidant and mitochondrial protector, a fundamentally different thing from swallowing a tablet. The research here is early, but the mechanism is biologically plausible and worth watching.
How Environmental Red Light Supports Sleep
Now the second type of red light, and this one is less complicated mechanistically, but no less important in practice.
Your ipRGCs, those melatonin-suppressing retinal cells, are tuned primarily to blue and green wavelengths. Red and amber light in the 600nm+ range has minimal effect on them at normal ambient intensities. There is a nuance worth being clear about: very bright red light at very high photon densities can cause some melatonin suppression, as research at extreme intensities has shown. But at the dim levels you'd use for home lighting in the evening, red and amber light essentially allows the body's natural melatonin rise to proceed undisturbed. The threshold is far above anything you'd encounter from a salt lamp or a warm amber bulb in the corner of your living room.
This matters enormously in practice. Standard Norwegian indoor lighting at 2700K to 4000K contains meaningful blue content that your retinal cells will respond to. When you're sitting under it at 9pm reading or watching TV, your eyes are receiving the same spectral signal as midday. Your pineal gland doesn't release melatonin properly. Your body doesn't register that sleep is approaching. And then you take a melatonin supplement to compensate for the thing your lighting is actively working against.
Switching to genuinely red and amber light sources in the evening, and using blue light blocking glasses (blålysbriller) if you're on any kind of screen, removes that interference. Your body's own melatonin rises as it's supposed to. No supplement required to patch over something that your environment was causing in the first place.
The Bigger Picture: Light Contrast
Here is what neither the supplement industry nor most Instagram wellness accounts want to discuss, because it can't be bottled and sold.
The real driver of good sleep is light contrast across the full day.
High-lux, ideally outdoor light in the morning and through the day signals to your suprachiasmatic nucleus, your master circadian clock, that it is daytime. Cortisol rises appropriately. Serotonin rises. Your body is metabolically active. Then, as light diminishes in both intensity and its spectral content toward the red end of the spectrum, the system reads the contrast and begins winding down. Melatonin rises. Core body temperature starts to drop. The parasympathetic nervous system takes over. You get genuinely sleepy at the right time.
Most of us have completely collapsed this contrast.
We wake into dimly lit apartments. We sit under mediocre office lighting all day. We spend the evening saturated in blue-enriched LED light from screens and overhead fixtures, sending our brains the noon signal all the way to midnight. Then we wonder why sleep is hard.
For us in Norway, this is particularly acute during mørketid. In Drammen by November, the sun barely clears the horizon. If you're commuting to work before sunrise and home after sunset, the only photons your eyes receive are artificial. The morning cortisol awakening response never properly fires. The evening melatonin rise is suppressed. The contrast your biology depends on simply isn't there. This is why supporting your daytime light environment with circadian and sleep-healthy lighting matters here as a genuine biological need, not just a lifestyle preference.
Temperature and stimulation in the evening are underrated too. Your core body temperature needs to drop by roughly one degree Celsius to initiate proper deep sleep. Alcohol raises core temperature and fragments sleep architecture even when it helps you fall asleep faster. Emotionally activating content at 10pm keeps the sympathetic nervous system fired. Eating late keeps your digestive and metabolic systems active when everything should be quieting. You can layer all the red light you like on top of these habits and sleep will still suffer.
So What Does the Ideal Evening Look Like?
Ninety minutes to two hours before bed, switch your room lighting over to red or amber only. This is environmental red light doing exactly what it's supposed to do, letting your melatonin rise without interference.
Around the same time, if you have a PBM panel, do your session. Ten to twenty minutes of therapeutic photobiomodulation. This is the cellular use, the actual stimulation of mitochondrial function and the downstream melatonin pathway documented in the research. It's not the same as the ambient lighting. Different mechanism, same evening window, both working in your favour.
Use blålysbriller (blue light blocking glasses) if you're on a screen. Keep the room cool. Stop eating two to three hours before. Give your nervous system time to come down.
As for melatonin supplements: low dose, short term, for resets. Not nightly, not at 10mg, not as a substitute for the light environment.
The red light panels collection has the devices I use and recommend, tested for actual wavelength output. The FAQ page covers the common questions, and if you want to know more about the approach behind all of this, the about page has that context.
Norwegian version of this post: https://lighttherapy.no/blogs/norsk/melatonin-vs-rodlys-sovn
FAQ
What is the difference between red light therapy and using red light in the evening?
These are two distinct things. Red light therapy, or photobiomodulation (fotobiomodulasjon), is a therapeutic session using a dedicated panel or device delivering specific wavelengths at a meaningful power density directly to your tissues, primarily to stimulate cellular function through the mitochondria. Environmental red light is simply choosing warm, red or amber light sources in your home during the evening instead of white LED or fluorescent lighting. Environmental red light works by avoiding the stimulation of your melatonin-suppressing retinal photoreceptors. The therapy panel works at the cellular level. Both support sleep through completely different mechanisms, and both are worth doing.
Does photobiomodulation actually increase melatonin levels?
The most directly relevant human evidence is a 2012 cohort study by Zhao et al. in the Journal of Athletic Training, which found significantly higher serum melatonin levels and improved sleep quality in athletes receiving 30 minutes of nightly whole-body red light irradiation over 14 days compared to a placebo group. A 2007 paper by Yeager et al. proposed melatonin as a principal mediator of red light's therapeutic effects, citing the biochemical overlap between what red light stimulates and what melatonin regulates. The evidence is promising and biologically coherent, but the research base is still relatively small. This is not a claim that PBM cures insomnia for everyone, but it is a claim worth taking seriously.
Can very bright red light still suppress melatonin?
Yes, at extreme intensities it can. Research on hamsters and humans at very high photon densities has shown small but measurable melatonin reductions at 630nm and 700nm wavelengths. The practical takeaway is this: at the dim ambient levels you'd use for evening home lighting, red and amber light is safe for your melatonin production. A PBM therapy session directed at your body (not staring into a bright panel) is also not a melatonin suppression risk. The concern applies primarily to very bright red light directly into the eyes, which is not how these tools are used in practice.
Hva er best for søvn: melatonin eller rødlysterapi? (What is best for sleep: melatonin or red light therapy?)
Both rødlysterapi (PBM) and environmental red light in the evening support the body's natural melatonin production, just through different mechanisms. Melatonin supplements give you a hormonal nudge without addressing why the body isn't producing it cleanly in the first place. For most of us in Norway during mørketid, building a proper light environment through the day and using both types of red light in the evening will consistently outperform a supplement taken against a background of disrupted light exposure.
What dose of melatonin is safe to take regularly?
Most sleep researchers not affiliated with supplement companies point to 0.5mg to 1mg as closer to what the body naturally produces. The 5mg to 10mg formulations common in American supplements are pharmacological doses that can downregulate your own melatonin receptors over time. Lower doses, timed correctly about an hour before your intended sleep time, are the approach that makes biological sense for short-term use. If you're taking high doses nightly for extended periods, it's worth asking why your body isn't producing melatonin naturally, and the answer to that is almost always somewhere in the light and stimulus environment.
Hjelper rødlys mot vinterdepresjon og mørketid? (Does red light help with seasonal depression and the dark season?)
Rødlysterapi in the PBM sense is not the same as the bright white light therapy used for vinterdepresjon, but the two approaches complement each other well as part of the full light arc. High-lux morning light for serotonin and cortisol, and a clear transition to lower red-spectrum light in the evening for melatonin. For us in Norway in winter, neither end of that contrast arrives naturally. Supporting both ends of the light day matters.
References
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Zhao J, Tian Y, Nie J, Xu J, Liu D. Red light and the sleep quality and endurance performance of Chinese female basketball players. Journal of Athletic Training. 2012 Nov-Dec;47(6):673-678. doi: 10.4085/1062-6050-47.6.08. PMID: 23182016. https://pubmed.ncbi.nlm.nih.gov/23182016/
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Yeager RL, Oleske DA, Sanders RA, Watkins JB 3rd, Eells JT, Henshel DS. Melatonin as a principal component of red light therapy. Medical Hypotheses. 2007;69(2):372-376. doi: 10.1016/j.mehy.2006.12.041. PMID: 17321060. https://pubmed.ncbi.nlm.nih.gov/17321060/
The information in this post is educational and based on published research and emerging science in quantum biology and photobiomodulation. It is not medical advice and should not replace a conversation with your GP or a qualified healthcare professional. If you are experiencing serious sleep disturbances or seasonal depression (vinterdepresjon), please seek professional support.