Red Light Research 2026
Wavelength “equivalence” vs real-world use: why choice and control matter
A practical look at why many red and near infrared wavelengths overlap in research, why outcomes still vary in real use, and why giving people control over which wavelengths they run is often the most honest design choice.
Why people get stuck on wavelength charts
The internet makes it feel like you can choose wrong
If you have spent time researching red and near infrared light, you will have seen it: charts that claim one exact wavelength is best for a specific outcome, lists that treat tiny differences as decisive, and product comparisons that imply your results depend on picking the right nanometre.
Here is the honest problem
Wavelengths are easy to compare on paper. Real use is not. When people argue over a 10 nm difference, they are usually skipping the parts that actually change what the body receives: distance, beam spread, treatment area, session time, and whether the routine is realistic enough to stick with.
The issue is not that wavelength discussions exist. It is that they are often presented as settled answers, while the evidence underneath them is still evolving and sometimes surprisingly overlapping.
What “wavelength equivalence” means
Similar ranges can produce similar outcomes
A useful reference on this topic is GembaRed’s wavelength equivalence guide, which asks a straightforward question: if a study used 810 nm, could 850 nm be close enough, or if a study used 670 nm, could 660 nm be close enough. Their core point is not that wavelength does not matter. It is that many commonly used red and near infrared wavelengths appear to overlap, and that nanometre-level certainty is often overstated in consumer discussions. The Wavelength Equivalence Guide to Red/NIR Light Therapy (GembaRed) .
Why the overlap argument is reasonable
The guide points out that there are not many randomised controlled trials directly comparing large numbers of wavelengths in humans, yet brands and influencers often speak as if those comparisons already exist. It also highlights a pattern that shows up repeatedly in the studies they do review: in many cases, both wavelengths improve outcomes, and the differences are often marginal rather than dramatic.
The most useful way to read “equivalence” is as a warning against false certainty. It is an argument for thinking in bands rather than single points, and for remembering that wavelength alone rarely explains outcomes.
Where equivalence breaks down in real life
Paper equivalence is not the same as user equivalence
Even if two wavelengths can lead to broadly similar outcomes in a controlled setting, they can still behave differently in real use. That is not a contradiction, it is the reality of how light behaves once it leaves a device.
Penetration and scattering
Light does not travel through tissue in the same way at every wavelength. Differences in scattering (how quickly light spreads out in tissue) and absorption influence how much light reaches deeper targets. This is one reason red and near infrared are often discussed as having different depth profiles, even when outcomes overlap in some studies. A practical overview that touches on the “optical window” concept and tissue interactions is covered in this PBM dosimetry and mechanisms review: The nuts and bolts of low-level laser (light) therapy (Chung et al., 2012) .
Perceived brightness and comfort
Two wavelengths can feel very different. Comfort matters because it affects adherence. A setup that looks perfect on paper but is unpleasant to sit with, or too intense to use consistently, tends to lose in the real world to a routine people actually maintain.
Delivery method changes the question
A wearable used directly on skin, a panel used at a distance, and a clinical whole-body system are not interchangeable. The same stated wavelength can translate into very different delivery depending on coverage, distance and beam angle. This is also why comparing devices by a single headline figure is often misleading.
Dose is not just a number
The equivalence discussion often intersects with dosing frameworks. You may see fluence (energy delivered per area, often written as J/cm²) and irradiance (power delivered per area, often written as mW/cm²). GembaRed also discusses the idea that different wavelengths carry different photon energy, and that dosing may need adjustment when comparing wavelengths. How Wavelength Affects Dosing for Red Light Therapy (GembaRed) . For a more formal PBM framing that includes dosimetry principles and the idea of a biphasic response (where more is not always better), this open full text review is also useful: PBM dosimetry and biphasic response overview (Chung et al., 2012) .
Why choice is the practical solution
Stop arguing about “best” and design for reality
Here is the point that cuts through most online arguments: if multiple wavelengths can overlap in outcome, then the most responsible design approach is not to insist there is one correct wavelength. It is to give people the ability to choose what they run and how they run it.
Choice matters because people differ. Comfort differs. Routines differ. Targets differ. Even within the same person, what feels useful on one day may not be the session they want on another. A rigid device forces one interpretation of correct use onto everyone.
A small but important mindset shift
Instead of asking which wavelength is best, a more useful question is whether your device gives you control to adjust as your understanding, comfort and routine change over time. That is a genuinely human question, and it tends to lead to better decisions than chasing perfection.
How to think about wavelength selection without overthinking
Use ranges and intent, not perfection
A practical way to approach wavelengths is to think in bands and intent rather than treating a single number as destiny. This keeps the conversation grounded and avoids the trap of false certainty.
1) Think in bands
Rather than obsessing over small differences, it is often more realistic to think in red ranges and near infrared ranges, then consider how those ranges fit the target depth and routine you have in mind.
2) Match the session to the target
Surface-focused sessions and deeper-focused sessions are different aims. Even if outcomes overlap, the experience and delivery can differ, especially when distance and coverage change.
3) Prioritise repeatability
The setup you can use consistently is often more valuable than the setup that looks perfect on a chart but is too intense, too complicated, or too hard to fit into daily life.
A simple rule
If a claim about the “best wavelength” does not also describe the treatment setup (distance, dose, schedule, delivery method), it is not a complete claim.
A quiet design shift: control over prescription
Why some modern systems are built differently
One of the more interesting shifts in premium hardware is that some systems now treat wavelength control as the point, rather than treating wavelength choice as a one-time purchasing decision. The aim is not to force a single interpretation of correct use, but to allow people to adapt light delivery without changing devices.
This is also why some designs separate wavelength groups and offer independent control, rather than bundling everything into one fixed mode. It keeps the device useful across different routines and preferences, and it fits better with what the evidence actually looks like: overlapping ranges, variable results, and a lot of nuance in real-world delivery.
If you want to see how NovaThera frames this from a design perspective, the approach is explained in the 9-Wave spectrum overview and the deeper explanation of system design is on What makes NovaThera better.
Practical takeaways
What to look for in a device, regardless of brand
Can you control what you run
Can you enable or disable specific wavelength groups, or are they locked together. Flexibility is not a gimmick if it helps you stay consistent and comfortable.
Are specs presented for real use
Be cautious of numbers that look impressive but do not match how people actually use a device. If the distance is unrealistic or the coverage is unclear, the spec is hard to interpret.
Does the format match your routine
A wearable, a panel and a whole-body system each create a different kind of routine. The best format is usually the one you will use repeatedly without friction.
A more human ending
The more useful question may not be which wavelength is best, but whether the device you choose lets you adjust as your understanding and preferences change. That is what turns research into something you can actually use, without needing to win an argument on the internet first.
Sources
Every source below is linked. If you want the core idea in its original form, start with the wavelength equivalence guide, then read the dosing article for the framework they reference. For a stronger scientific backbone on tissue interactions, dosimetry and the “more is not always better” concept, the PBM mechanisms and dosimetry review is a helpful anchor.