How Much Power Does My Red Light Panel Need?
It's one of the most common questions we get, and it's a fair one. Red light panels are sold on big numbers: 300W, 1000W, 1500W. It's natural to assume the bigger the number, the better the results.
The honest answer is more interesting than that. "Power" means several different things in red light therapy and the number printed on the box is often the least useful one. Once you understand what the research actually measures, choosing a panel gets much simpler and you're far less likely to overspend or underbuy.
The short answer
Most people don't need the most powerful panel. They need a panel that delivers enough light to the right area, at a sensible distance, in a session length they'll actually stick to. That comes down to three things:
- Irradiance: how much light energy reaches your skin per second (measured in mW/cm²)
- Dose: how much total light energy you receive in a session (measured in J/cm²)
- Coverage: how much of your body the panel lights up at once
Wattage feeds into all three, but it doesn't tell you any of them directly.
Why wattage is a misleading number
The wattage on a red light panel usually describes the electrical rating of the LEDs, or the power the unit draws from the wall. It's a measure of electricity going in, not therapeutic light coming out.
Two panels with identical wattage can deliver very different amounts of light to your skin depending on LED quality, lens design, beam angle and how efficiently the electronics run. That's why, at Magma, we list wattage as a "power class": it's a useful way to compare sizes within our own range, but it isn't the figure that matters biologically.
The research literature doesn't use wattage at the wall either. Scientists describe treatments in terms of wavelength, irradiance and energy density. In fact, researchers have pointed out that the difficulty of choosing between many illumination parameters, including wavelength, fluence, power density, pulse structure and treatment timing, is one reason the field has produced negative studies alongside positive ones. Getting the parameters right matters more than raw power. doaj
Irradiance: the number worth looking for
Irradiance is the intensity of light landing on a given area of skin, usually expressed in milliwatts per square centimetre (mW/cm²). It's the closest thing to "real" power you'll find on a spec sheet.
Two things to watch for:
It always depends on distance. Irradiance drops quickly as you move away from the panel, so a figure is meaningless without the distance it was measured at. Our panels are rated at 6 inches (around 15 cm): the MLP92 Pro, for example, delivers 175 mW/cm² at that distance. Step back to a foot or more and the figure falls substantially. When comparing brands, always compare at the same distance.
Measurement methods vary. Irradiance can be measured with different equipment, and not all meters read red and near-infrared light equally well. This isn't a problem unique to consumer devices: a review of the photobiomodulation literature identified incomplete and unverified irradiation parameters, miscalculation of dose, and misuse of terminology as three main concerns across the research itself. Treat any headline figure as a guide, not gospel. springer
Dose: what actually drives results
If irradiance is the speed, dose is the distance travelled. Dose (sometimes called energy density or fluence) is simply irradiance multiplied by time:
Dose (J/cm²) = irradiance (W/cm²) × time (seconds)
So a panel delivering 100 mW/cm² (0.1 W/cm²) for 60 seconds gives you 6 J/cm². Run it for 10 minutes and you're at 60 J/cm².
This is the key insight most buyers miss: a less intense panel used for a little longer can deliver the same dose as a more intense panel used for less time. Higher irradiance mainly buys you shorter sessions, and the ability to stand further back while still getting a meaningful dose.
What dose should you be aiming for? The research doesn't give a single answer, and anyone who tells you otherwise is overselling. Even after more than 50 years of study, there is still no agreement on the parameters and protocols for clinical use. What we can say is that doses vary by target tissue. Recommendations for surface dose run as high as 50 J/cm², and a large review found that tissues rich in mitochondria, such as muscle and nerve, tended to respond to lower doses than tissues with fewer mitochondria, such as skin, tendon and cartilage, although the authors were clear the results were highly variable. nihuj
More isn't always better
Here's the part that surprises people. In red light therapy, there appears to be a sweet spot, and going beyond it can reduce the benefit rather than increase it.
This is known as the biphasic dose response, or the Arndt-Schulz curve. It has been frequently observed that low levels of light stimulate and repair tissue much more effectively than higher levels. Too little light and nothing much happens; the right amount produces a response; far too much can blunt it. doaj
It's worth being precise about the strength of this evidence. The biphasic pattern has been demonstrated in cell studies and animal experiments, but it's less well mapped in human trials. Still, it's a strong reason to be sceptical of the idea that the most powerful panel, used for the longest time, will give you the best results. doaj
The practical takeaway: a quality panel used consistently at a sensible distance and session length will serve you better than an oversized one used too close for too long.
Coverage: the factor people underestimate
If irradiance and dose answer "how much light", coverage answers "how much of me". This is where panel size genuinely matters, and where the bigger panels in any range earn their price.
A small panel can deliver excellent irradiance to your face or a single joint. But if you want to treat your whole back, both legs, or your full body after training, a small panel means multiple sessions, repositioning, and a lot more time. Most people who buy too small end up using it less, and consistency is what produces results.
Matching a panel to what you want
Rather than asking "how many watts do I need?", ask "what am I treating, and how much time will I realistically give it?"
Face, skin and targeted areas. Skin is the most researched application, with reviews describing beneficial effects on wrinkles, acne scars, hypertrophic scars and burn healing. You don't need a huge panel for this. A compact unit like the MLP32 Table Top (120W class, 157 mW/cm² at 6") or the MLP64 Pro (240W class, 162 mW/cm²) covers the face, neck and décolletage comfortably. nih
Specific joints or muscle groups. A knee, shoulder or lower back. The MLP64 Pro or MLP92 Pro (360W class, 175 mW/cm²) give you enough height to cover a decent area without constant repositioning.
Half-body or larger areas. The MLP92w Pro (720W class, 181 mW/cm², 92 x 42 cm) is wide enough to light most of your torso or both legs at once. This is where many of our customers who train regularly land.
Full body, minimal fuss. The MLP154 Pro (1200W class, 194 mW/cm², 153 x 42 cm) and MLP184 Pro (1440W class, 184 x 42 cm) cover you head to thigh or head to toe in a single session. You're paying for coverage and convenience, not for some special "dose" a smaller panel can't reach.
Notice that the irradiance figures across our range are all in a similar band. That's deliberate. As the panels get bigger, they don't get dramatically more intense per square centimetre; they cover more of you. That's the honest picture for most well-designed panels.
A quick checklist for comparing panels
When you're weighing up options, from us or anyone else, look for:
- Irradiance with a stated distance. No distance, no meaningful number.
- Wavelengths that match the research. Red (around 630–670 nm) and near-infrared (around 810–850 nm) are the most studied ranges.
- Size relative to your goal. Will it cover the area you care about in one go?
- A realistic session length. Can you hit your target dose in 10–20 minutes at a comfortable distance?
- Low EMF and proper certification. UKCA and CE marks matter for anything plugged into your mains.
- A trial period. The best test is whether you'll actually use it.
The bottom line
Your red light panel doesn't need the biggest wattage on the market. It needs to deliver a sensible dose of the right wavelengths to the area you want to treat, in a session you'll stick to.
For targeted use and skin, a compact panel is genuinely enough. For recovery, larger areas or full-body sessions, size is worth investing in, not because the light is more "powerful", but because it reaches more of you at once.
If you're still unsure which panel suits your goals, get in touch. We'd rather help you choose the right one than sell you the biggest one.
This article is for general information only and isn't medical advice. If you have a medical condition, are pregnant, take photosensitising medication or have concerns about your eyes, speak to your GP before starting red light therapy.
References
- Huang YY, Chen AC, Carroll JD, Hamblin MR. Biphasic dose response in low level light therapy. Dose Response. 2009;7(4):358–383. https://pubmed.ncbi.nlm.nih.gov/20011653/
- Huang YY, Sharma SK, Carroll J, Hamblin MR. Biphasic dose response in low level light therapy – an update. Dose Response. 2011;9(4):602–618. https://pmc.ncbi.nlm.nih.gov/articles/PMC3315174
- Zein R, Selting W, Hamblin MR. Review of light parameters and photobiomodulation efficacy: dive into complexity. J Biomed Opt. 2018;23(12):120901. https://pmc.ncbi.nlm.nih.gov/articles/PMC8355782/
- Avci P, Gupta A, Sadasivam M, et al. Low-level laser (light) therapy (LLLT) in skin: stimulating, healing, restoring. Semin Cutan Med Surg. 2013;32(1):41–52. https://pubmed.ncbi.nlm.nih.gov/24049929/
- Hadis MA, Zainal SA, Holder MJ, et al. The dark art of light measurement: accurate radiometry for low-level light therapy. Lasers Med Sci. 2016;31(4):789–809. https://doi.org/10.1007/s10103-016-1914-y
