September 3, 2025

How Many Watts is Red Light Therapy? Total Joules Dosing Calculator!

How many Watts do you need for full body Red Light Therapy?

A consumer could obtain the latest generation overpowered LED panel system and not have to worry about having inadequate power. If anything, they would do well to turn down the power and only use the maximum settings for specific purposes (or never).

In another recent interview Professor Glen Jeffery gives caution:

"Most of which are far too powerful, you do not want to put vast amounts of energy into your body, you really don't."

https://youtu.be/ak5gHOOYdLg?si=b0rLkrP-ECu1GAyF&t=2394

So how can we be assured we are getting adequate energy doses without excessive exposure? There seems to be opposing pressures from RLT Influencers to use the most power that a human can tolerate without overt harm, and real PBM Researchers recommending low energies and adequate exposure times.

The original criteria for Red Light Therapy devices was that they needed to emit >100mW/cm^2 at 6 inches away to be effective. This turned out to be a complete fabrication by RLT influencers to justify falsely high measurements made by Solar Power Meters.

Losing that criteria left a void in the industry. Consumers are left without any independent scientific criteria that can assure them that their devices deliver enough power to be effective.

Ultimately, many opt to feel the physical pain of excessive intensity on their skin - rather than suffer the mental anguish that their device could be inadequately powered. At least when you are burning your skin, then you can be confident that your device does not lack power. Especially when most studies don't report any feeling of heat at all, or at-most a mild warming feeling.

We can avoid the self-flagellation with overpowered devices by calculating the wattage required to meet the dosing recommendations from one of worlds leading experts. This way we can check the science-backed wattage from a credible expert against 3rd party lab measurements to see if devices are adequate.

Like how a real scientific industry actually works. We start with the independent science, and then check if the accurate product specifications meet the criteria. As opposed to RLT Influencers start with the affiliate product they intend to sell, and then shoehorn the science to match it.

Total Joules Dosing Red Light Therapy:

The proper way to dose Red Light Therapy according to Dr. Hamblin is based on the Total Joules delivered.

"The most important parameter is how many Total Joules you put on the head" - Dr. Hamblin

https://youtu.be/XyO_ETeicE8?si=802w1Abz8i9HFXT1

And:

"So, total energy is a big deal. And with these whole body light beds, you can absorb a hundred thousand joules of energy, relatively... 20 minutes sometimes, something like that. Fifty to one hundred thousand Joules of energy" - Dr. Hamblin

https://youtu.be/O4iL8V1Xpnk?si=f_9OYmNnm6sM18k8

According to Dr. Hamblin, the Total Joules is the most important parameter for dosing red light therapy. It is a big deal, even though many consumers haven't gotten this memo yet.

Some reference ranges for Total Joules include:

Full Body Red Light Therapy: 50,000 to 100,000 Joules [YouTube]
Torso Systemic Treatments Range: 5,000 to 30,000 Joules [Link]
Brain Helmet Dose: 2,000 to 6,000 J [YouTube]
Targeted Muscle Treatments: 20 to 300 Joules [1]
WALT guidelines recommend 4 to 12 Joules per point [WALT]

This is a pivotal shift away from J/cm^2 for dosing. Even though Dr. Hamblin has been explaining proper dosing for years, many brands and influencers have chosen to ignore his dosing recommendations.

Total Joules Dosing Calculator:

Calculating the Total Joules dose is a similar equation as calculating the J/cm^2 dose like our previous calculators.

Total Joules (J) = Watts (W) x Exposure Time (seconds)

The key is obtaining the accurate Optical Watts output from your device. Which is best measured inside an Integrating Sphere that collects all the power to a single sensor. This is a standard service provided by many 3rd party light laboratories.

Pictures provided by LightLab International, Allentown PA

So, when you know your desired dose (Joules) and Optical Power (Watts) of your device, then you can input the numbers into the calculator to find the required exposure time.

Calculator placeholder

Many clinical studies with large LED arrays are non-contact (or essentially non-contact since they don't press into the skin). So generally a reflection correction factor would not be required like with our other dosing calculator. You could manually add a correction factor of 2.5x to your time if you know the study you are referencing is with skin contact.

You can also use the checkbox to input the electrical power of your device and we will make a conversion calculation to the optical power output. The full explanation for that will be later in this blog.

How Many Watts do you need for Full Body Red Light Therapy?

In order to figure out the required watts for red light therapy, we can work backwards from the recommended doses.

In a recent interviews, Dr. Hamblin recommends 50 to 100 Thousand Joules in about 15-20 minutes. [YouTube]

With some math we can determine a range of Watts required:

50K Joules for 20 minutes = 42 Watts
100k Joules for 15 minutes = 111 Watts

Based on the recommended dosing ranges established by Dr. Hamblin, a good range for a full body red light panel is 42 to 111 Watts.

Optical Watts vs Electrical Watts vs Rated Watts

An important note in the previous section is that we are discussing the required Optical Power (W). That is the power emitted from the panel in the form of electromagnetic radiation (light).

The LED panel consumes Electrical Power (Watts), and then some of that power is converted by the LEDs into Optical Power (also Watts). Both use the same unit Watts because power can change forms from electricity into electromagnetic waves.

The name of many panels often includes the Rated Watts (i.e. MaxProElite 300, 600, 900). This is the maximum power rating of the LEDs combined. However, it is industry practice to run LEDs at less than half their rated power to preserve optical efficiency, longevity, and reduce heating.

Thus, the Rated Power often does not consistently correlate to any relevant physical measurement. Especially when there is variability in Ratings like 3W, 5W, 10W, double chip, triple chip, COB, etc. Now in many cases those numbers don't even correlate to the Rated Watts anymore, and they are just arbitrary numbers as another "industry standard" that has no basis in reality.

Shopping for Optical Watts

Shopping based on Optical Watts is often easier than shopping for Intensity (mW/cm^2). Many major brands are unwilling to disclose their real intensity. However, they may share their 3rd party tested Optical Watts.

Here is a table of data compiled from 3rd party test reports of several companies that were sent to me.

Note the testing was conducted in 2022, so the data above may not reflect the latest generations or updates from these brands. But we can still do some interesting analysis with it.

We see the Optical Power range of most of these panels are between 81 to 184 Watts. This is more than sufficient to meet the therapeutic range established earlier. In just 10 minutes they deliver more than sufficient Total Joules dose. So we can be assured with just 15 or 20 minutes (7.5-10 minutes each side) can get more than enough Total Joules for effective full body Red Light Therapy.

Even a single LED panel above that does not cover the entire body is sufficient to deliver enough power and energy for a full body effect.

How Much Intensity do You Need for Full Body Red Light Therapy?

Total Joules and Optical Watts are the most important parameters for effective red light therapy according to leading researcher Dr. Hamblin in many interviews.

This simplifies our approach to dosing red light therapy, but there is a lack of education on this terminology. Most of the dosing marketing narratives are centered around Intensity (mW/cm^2) and Fluence (J/cm^2).

So let us review how Dr. Hamblin's recommendations translate into Intensity (mW/cm^2) and Fluence (J/cm^2).

In one old interview, Dr. Hamblin says that 10-20 mW/cm^2 is high in the context of full body red light therapy, since he knows that the Total Joules absorbed in 15-20 minutes will be very high.

But again, let us do the math in reverse.

We know we need 42 to 111 Watts. And we know the standard dimensions of a single full-body panel are often 9 to 11 inches wide by 36 to 42 inches tall.

Thus, we have the Optical Watts and the Area. We can easily calculate the Power Density (Intensity, Irradiance, mW/cm^2).

Based on the dimensions above, a small full body panel is 2,093 cm^2 and a larger one would be 2,996 cm^2.

42,000 mW / 2,093 cm^2 = 20 mW/cm^2
42,000 mW / 2,996 cm^2 = 14 mW/cm^2
111,000 mW / 2,093 cm^2 = 53 mW/cm^2
111,000 mW / 2,996 cm^2 = 37 mW/cm^2

So even the first generation of "full body" LED panels were in the appropriate range of intensity all along 14 to 53 mW/cm^2. Note that this this would represent an "average" intensity over an area, since we know in reality the light is not uniform and spreads with distance from the panel (but not by much).

A good rule of thumb emerges. The bigger the device, the lower the intensity is appropriate. Because we are scientifically targeting a specific dose (Total Joules). Which is exactly the point Dr. Hamblin was making all those years ago. This is what makes using large LED panels very safe, they can use very low intensities to deliver high total joules dose.

How Much Dose is Recommended for Full Body Red Light Therapy?

And now we can finally calculate J/cm^2 that this recommendation ends up delivering. If you have read our other blogs, at this point it seems the J/cm^2 is the least important parameter for dosing Red Light Therapy.

14 mW/cm^2 for 20 minutes = 16.8 J/cm^2
53 mW/cm^2 for 15 minutes = 47.7 J/cm^2

This is a fairly common dosing range of 16 - 48 J/cm^2. So even though people use the wrong dosing metric, they seem to accidentally align well with the total joules dosing. Perhaps not a coincidence as the numbers would match up in empirical studies as what is shown to be effective.

Finding Total Watts based on estimated Efficiency:

The best way to measure the Total Watts of a panel is to put it inside an Integrating Sphere. It collects all the light into one sensor, thus measuring the Total Optical Watts with ease.

However, many brands do not have this data yet. Getting 3rd party testing is very expensive. To be clear, the testing itself is actually very cheap - about $700 per device. The real cost is that brands will incriminate themselves if they obtain accurate measurements that contradicts their false intensity advertising. Or they put themselves at a marketing disadvantage if they stop false advertising. Which would also erode affiliate commissions for influencers, which is why they are shy about calling it out for their top brands.

A rough way to calculate the Total Watts of a panel would be to take the Intensity (mW/cm^2) and multiply by the treatment area of the panel (cm^2).

However, this can lead to erroneous results as we know the spatial intensity distribution from a panel is not uniform. One could take multiple measurements in a 2D grid to get a better estimate of power distribution and Total Watts, but that can also lead to errors in an uncontrolled environment without proper qualifications.

One solution would be to use the estimated optical efficiency of a panel. Thanks to finally having a large group of 3rd party data, we calculate the average optical efficiency of these popular types of panels.

The conversion of electrical power to optical power is not perfectly efficient, the inefficiency is typically lost as heat. It depends on the the efficiency of the LEDs, design of the circuit boards, power adapter efficiencies, and power consumed by accessories like fans and LCD screens. In other words, it could be possible that a panel could consume a lot of power but be very inefficient in the conversion to optical power. But generally we would not expect that to happen by a large margin.

We seem to have a consistent range of 35 to 41% efficiency and an average efficiency of 37%

So lets say we have the RL Pro series from Shenzhen Idea Light, all we need to do is measure the consumed power with a Kill-A-Watt meter or similar power consumption outlet meter. These are fairly cheap and common at hardware stores for under $30.

Then multiply the consumed power by the efficiency percentage to estimate the optical power output.

For example, the RLPro300 consumes 352 Watts, then we multiply by 0.37 as a conversion to Optical Watts. Then we get 352 X 0.37 = 130 Watts. This is above the required optical wattage even from a relatively small "full body" panel.

This is a reliable estimate especially for SZ Idea Light. Since they are likely the supplier for several of the brands in the table above. So we are safe to assume the efficiency will be similar to those we analyze in the table.

In other words, with a cheap Kill-A-Watt meter and an Alibaba panel the consumer can calculate dose more accurately than buying a name brand panel at 2-3x less cost. Since the name brand panels are mostly deceptive with their output claims and their influencers are strategically confused about dosing.

Based on 35% efficiency (worst case), we can calculate that a panel would need to consume at least 120 to 317 Watts to emit the required 42 to 111 Optical Power. So now we have a minimum requirement for Electrical Power from panels to additionally check if they are powerful enough.

The electrical power consumed by LED panels is often provided by brands on their specification pages. They should have no problem disclosing it since it is easily measured and may be required for consumers to check their electrical requirements.

Then you can convert the Electrical Power to Optical Power with a 35-41% factor and then calculate the Total Joules dose. Which we added to the calculator in the beginning of this blog.

Note that in Electrical Power a standard 15 Amp breaker will trip around 1400-1800 Watts. So if an LED panel system risks tripping a breaker, it is 5x more powerful than required for a therapeutic effect.

How Many Panels do you Need for Full Body Red Light Therapy?

It only takes a single panel of reasonable size and power to deliver full-body red light therapy. Perhaps 2 panels set up one in front and one in back could save additional time and give some additional satisfaction.

Upselling oversized systems would actually make it more difficult to estimate Total Joules dosing, as most of the energy would be missing the user. Oversized systems benefit the salesperson and not so much the consumer.

Few will recall that all the major Red Light Therapy brands originally sold "full body" panels that were not even modular as their first generations. Yet there were no complaints at the time from affiliate influencers that those panels were too small.

Conclusion

The mainstream recommendation for effective Red Light Therapy is that the intensity needs to be at least 100mW/cm^2 at 6 inches away. Many consumers would be disappointed to learn that the vast majority of panels do not emit that much power according to accurate measurements.

Thus, according to the RLT Influencers own made-up criteria, the products they have been endorsing for years are ineffective. Influencers haven't retracted that claim for fear of exposing themselves as frauds. They would rather see people harmed by excessively high intensity than to take accountability for their mistakes. As the saying goes: the cover-up is always worse than the crime.

This causes uncertainty for consumers to shop with confidence that they are buying an effective device. The biggest doubters of the science are clearly the major brands and RLT influencers themselves. That is why they keep increasing the intensity and turning their devices into LED Heat Lamps. They no longer promote true non-thermal Photobiomodulation with evidence-based parameters, and they even rebranded their pseudoscience narrative as "unconventional" Photobiomodulation.

The sentiment from many leading researchers like Dr. Arany, Dr. Hamblin, and Dr. Jeffery is that the current LED panels on the market are more than sufficient to deliver adequate power for therapeutic light therapy. If anything, many of the leading devices are too powerful and risk overdosing.

To resist the fearmongering from influencers that devices are lacking in power, we can calculate the minimum power required. To do that we worked backwards from the dosing recommendation from Dr. Hamblin to ensure we reach adequate Total Joules dose in 15 minutes.

This way the consumer can be confident that their purchases meet an independent scientific threshold of power for full body red light therapy. Rather than influencers are constantly changing their standards match the latest generation panel from their favorite affiliate brand.

Here we found an Optical Power range of only 42 to 111 Watts is sufficient for full body red light therapy. This translates to an Electrical Power Consumption of 120 to 317 Watts.

And we can confirm from 3rd party data that many brands can easily meet this threshold with just a single large panel. Even from data that is already 3 years old.

This way designers could make devices that are the minimum wattage and size to deliver the most practical, affordable, and space-saving devices. Consumers could shop with more confidence knowing their purchases meet the minimum threshold for therapeutic effectiveness.

Due to basic economy of scale - overpowered devices have the highest potential for best value. However, the best value does not necessarily mean the best effectiveness, as value is an arbitrary metric of Watts per Dollar. Especially now we start seeing people using high value devices are uncomfortably hot or suffering overstimulation side effects.

There is still an emphasis on delivering the required energy in a reasonable range of time from 10 to 20 minutes. Higher power and lower exposure time would lead to inconsistent results, at best.

So even though there are differences in dosing theories, it ultimately boils down to the same ranges of intensities, energy, and timing that we have been recommending for years.

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YouTube References:

Shining a Light on the Brain for Healing with Dr Michael Hamblin

Stefano Sinicropi MD