If you’re working out how to choose a red light therapy device in Australia, the spec sheet can read like a foreign language. This page explains what those numbers mean and which ones are worth looking for.
Before you read on: the figures below describe what researchers have used and reported. They are things to look for on a spec sheet, not guarantees. No specification can tell you what a device will do for any particular person.
This is general information, not medical advice, and it doesn’t recommend any product. For advice about your own health or skin, please talk with your GP, dermatologist or another health professional.
Which wavelengths are best researched?
Wavelength is the colour of the light, measured in nanometres (nm). A 2016 review by de Freitas and Hamblin describes the light used in this field as usually falling between about 600–700 nm (red) and 780–1,100 nm (near-infrared, which is invisible).[2] A 2026 product guide by Spongberg and colleagues states that red light at about 630–660 nm and near-infrared at about 830–850 nm are the wavelengths most commonly used.[1] The same guide describes red light as being absorbed closer to the skin’s surface, and near-infrared as reaching deeper layers.[1]
Simple red light therapy wavelength chart
| Wavelength range | What the sources say | Source |
|---|---|---|
| ~630–660 nm (red) | Among the most commonly used red wavelengths | [1] |
| ~830–850 nm (near-infrared) | Among the most commonly used near-infrared wavelengths | [1] |
| ~600–700 nm and ~780–1,100 nm | Broad ranges usually used in this field | [2] |
| 1,072 nm | Used in some at-home mask studies included in a 2026 review | [3] |
| 940 nm | No direct comparison found in our sources | n/a |
Does 1060 nm matter? Our sources don’t specifically examine 1,060 nm. A 2026 systematic review of at-home LED masks (8 studies, 365 people) included studies that used wavelengths from 440 nm up to 1,072 nm, and some of those used 1,072 nm light.[3] So longer wavelengths have been studied, but the evidence is thinner than for 630–660 nm and 830–850 nm.
850 nm vs 940 nm. We didn’t find a source in our reviewed material that directly compares these two. 940 nm falls within the broad near-infrared range described above,[2] but the evidence specific to it is thinner. A more useful question is whether the seller can show the wavelength was measured.
What is irradiance in red light therapy? (mW/cm² and J/cm²)
Irradiance (sometimes called power density) is the power of the light divided by the area it falls on, usually shown as mW/cm² (milliwatts per square centimetre).[2]
Dose, often written as fluence or energy density in J/cm² (joules per square centimetre), describes how much light energy reaches each square centimetre over a session. Energy equals power multiplied by time,[2] so you can estimate dose like this:
irradiance (mW/cm²) × time (seconds) ÷ 1,000 = dose (J/cm²)
Worked example: 30 mW/cm² for 5 minutes (300 seconds) is 30 × 300 = 9,000 mJ/cm², and ÷ 1,000 that’s 9 J/cm².
Simple dose calculator: illustrative examples
| Irradiance at the stated distance | Time | Dose | Notes |
|---|---|---|---|
| 30 mW/cm² | 300 s (5 min) | 9 J/cm² | Worked example above |
| 20 mW/cm² | 300 s (5 min) | 6 J/cm² | Illustrative |
| 60 mW/cm² | 120 s (2 min) | 7.2 J/cm² | Illustrative |
| 30 mW/cm² | 600 s (10 min) | 18 J/cm² | Illustrative |
These rows are maths examples, not a dosing chart or a recommendation. The 2026 product guide reports that published skin-focused research has typically used irradiance levels of about 20–60 mW/cm² and doses of about 4–18 J/cm². It also notes that this wide spread reflects a lack of standardisation between studies.[1] De Freitas and Hamblin add that dose in J/cm² is a useful descriptor but can be unreliable. It assumes a short session at high irradiance behaves the same as a long session at low irradiance, and that isn’t always the case.[2]
Why distance from skin changes everything
The irradiance on a spec sheet only applies at the distance where it was measured. As a general principle, light spreads out as you move away from its source, so less of it falls on each square centimetre of skin and irradiance drops. That also changes the dose over the same session time.
That’s why the distance from face or skin given in the instructions matters. A figure like “100 mW/cm²” with no distance attached can’t be compared with anything. Look for irradiance stated at a specific distance, ideally the distance the instructions tell you to use.
Why LED count and watts don’t tell you the light output
Many listings lead with the number of LEDs or a wattage figure. Neither tells you how much light reaches your skin:
- LED count says nothing about each LED’s output, wavelength accuracy, or how the light spreads.
- Wall-socket watts usually describe electrical power drawn from the wall. Some of that becomes heat, and some powers fans and electronics, so it isn’t the same as the light delivered.
The useful number is measured irradiance (mW/cm²) at a stated distance and wavelength.
What makes a spec sheet trustworthy?
The 2026 product guide suggests looking for sellers that clearly list wavelengths, disclose irradiance and dose, and link to published studies. It also suggests searching independent databases such as PubMed, ClinicalTrials.gov or Google Scholar for research on a device or brand.[1] It’s also worth looking for:
- Measured, not calculated, output. Irradiance measured with a suitable meter at a stated distance, not estimated from LED ratings.
- Independent testing. A report from a third-party lab, with the date, the method and the distance used.
- Wavelength confirmation. Ideally a spectral measurement showing where the output actually peaks.
- Consistency. The same figures in the website, manual and test report.
How often and how long?
There’s no single rule that fits every device. Research describes a biphasic dose response, where too little light may produce no measurable effect and too much may produce none or even an inhibitory one.[2] The 2026 product guide also highlights keeping session time within the stated limits for this reason.[1]
Devices differ in output and recommended distance, so follow your device’s own instructions on how often, how long and how far away to use it. Using a device for longer or more often than instructed isn’t supported by the research summarised here.
Checklist before you buy
- Wavelengths are stated, and ideally measured.
- Irradiance (mW/cm²) is given at a stated distance.
- There’s an independent test report with its method and date.
- The instructions clearly cover distance, session time and frequency.
- Marketing doesn’t lean on LED count or wall watts.
- If a therapeutic claim is made, check the ARTG entry. See our guide to TGA and ARTG.
- If you have a skin or health concern, you’ve spoken with a health professional first.
FAQ
Which wavelength range is most researched? Sources describe red light at about 630–660 nm and near-infrared at about 830–850 nm as the most commonly used.[1]
Is 1060 nm or 940 nm better than 850 nm? Our sources don’t directly compare them. Some mask studies used 1,072 nm,[3] but evidence for these longer wavelengths is thinner.
What is irradiance in red light therapy? It’s light power per area, in mW/cm², measured at a particular distance.[2]
How do I calculate dose? Multiply irradiance (mW/cm²) by seconds and divide by 1,000 to get J/cm². For example, 30 × 300 ÷ 1,000 = 9 J/cm².[2]
What irradiance level and dose have studies used? One 2026 guide reports about 20–60 mW/cm² and 4–18 J/cm² in skin-focused research. These are research figures, not a target.[1]
How far should I sit from the device? Use the distance in your device’s instructions. The stated irradiance only applies at the distance it was measured.
How often and how long should I use a device? Follow your device’s instructions. There’s no universal rule, and research describes a dose window.[1][2]
For personal advice about whether red light therapy suits you, please talk with your GP or another health professional.
Related reading on our blog
- How to choose a red light therapy device
- 660nm and 850nm red light therapy: what buyers should know
- How to choose an at-home red light device (mask, belt or mat)
Sources
- Spongberg CV, Stack ER, Aprigliano C, Grinis D, Sawicki S, Elway M. What to look for in red light therapy: a product guide backed by science. Cureus. 2026. https://doi.org/10.7759/cureus.105378 (PMC: https://pmc.ncbi.nlm.nih.gov/articles/PMC13085462/)
- de Freitas LF, Hamblin MR. Proposed mechanisms of photobiomodulation or low-level light therapy. IEEE Journal of Selected Topics in Quantum Electronics. 2016;22(3). https://doi.org/10.1109/JSTQE.2016.2561201
- Das RK, Thayer WP, Kubiak CA, et al. Efficacy and safety of at-home light-emitting diode photobiomodulation for facial rejuvenation: a systematic review. Aesthetic Plastic Surgery. 2026. https://link.springer.com/article/10.1007/s00266-026-06333-w
