Best Wattage for Red Light Therapy
If buying a red light therapy device were like buying other health and wellness items, you’d just ask “What is the best wattage for red light therapy?” and you’d be done. It’s not that easy with light therapy, because you care more about the LIGHT than you do the WATTS. But I’ll show you a shortcut to make it easy.
The wattage of a red light therapy device is almost irrelevant to its effectiveness. It’s possible to have a lamp with high wattage but that just doesn’t deliver the photons (packets of light energy). Instead, you want to look at “irradiance,” or even better, look for “joules.”
How Mito Red Light Solved the Thorny Problem of Irradiance
I write huge articles explaining red light therapy because it’s just not obvious how to get a proper dose of light. Incorrect dosage leads to treatment failure.
Irradiance is a huge problem in red light therapy shopping. One cannot trust the irradiance values manufacturers give because so many vendors use the wrong meter type to measure light delivery. Mito Red Light now gives us fluence, a solid way to measure a device’s power.
Get High Power, but Not Too High
While it’s cumbersome to calculate treatment time using irradiance, it’s crazy how easy it is to calculate treatment time using fluence.
The biological magic stops if the light is delivered too quickly.
But a powerful light gives you a shorter treatment time.
The Best Wattage for Red Light Therapy is “Irradiance” or “Joules”
Comparing wattage matters when buying a refrigerator or other appliance, but it’s a bit of a useless value when comparing red light therapy devices.
Wattage is not a reliable value that informs you of how quickly the device delivers light.
We can’t know just by looking at the wattage value. A red light therapy device is a black box. No wattage or amperage statement on the device tells us the photon irradiance.
What we need is the photon delivery value, which is irradiance.
Irradiance is the rate at which the light delivers photons from a given distance per second.
The device’s wattage doesn’t tell us the irradiance.
We need to get that from the vendor who measured light output with a proper meter.
Irradiance is No Longer Above Reproach
We usually use irradiance to calculate treatment time.
Once one vendor inflated their irradiance values, others did too so as not to seem weak by comparison.
Inflated irradiance values lead to vastly understated treatment times, which lead to under doses, which lead to failures.
By publishing fluence, Mito Red Light gives us a valid value to calculate treatment time.
Use irradiance when you have a valid value. Use fluence when you can get this value.
Below you’ll learn how to calculate treatment time using irradiance or fluence.
How to Calculate Dose Using Irradiance
If you have a reliable irradiance value, you can use this guide to calculate your treatment time per session.
I will show you how in this section.
However.
These instructions are here for the absolute red light therapy geek.
I encourage anyone who has a life to buy from a vendor that publishes certified fluence values, and then you can just skip this section.
You need a reliable irradiance value for any of this to make sense.
Are you sure you don’t want to skip this section?
You’re still here?
OK, let’s talk about how to calculate treatment time given a reliable irradiance value.
Irradiance is Per Second and Expressed in Milliwatts
Let’s say a red light therapy device delivers 50 milliwatts per square centimeter per second, which we write like this: 50 mW/cm^2.
That irradiance is incomplete. It delivers 50 milliwatts from what distance? In what amount of time?
An irradiance value is meaningless unless we know how far away the light is from the target.
For the sake of this example, we’ll pick 6 inches as the distance, and one second is the interval. Now our irradiance is 50 mW/cm^2 at 6 inches distance per second.
For the time factor, you should know that “irradiance” assumes a one-second interval unless stated otherwise.
Everything you need to know about dosage is in that statement:
- set the energy to 50 milliwatts
- the time is per second
- the given distance is 6 inches
We will use this data to calculate session time to get a target dose.
You can always skip this and read the easy fluence instructions.
Don’t say I didn’t offer you an out.
Treatment Time Calculation Step 1: Convert Irradiance to one Minute
Irradiance per second is too short to get a meaningful treatment time, so we will convert irradiance from one second to one minute.
To get irradiance per minute, multiply irradiance by 60 seconds:
(50 mW/cm^2 per second @ 6 inches x 60 seconds per minute) = 3,000 mW/cm^2 per minute @ 6 inches
Our new irradiance delivers the exact same energy, but per minute: 3,000 mW/cm^2 at 6 inches per minute
Treatment Time Calculation Step 2: Derive Joules (Fluence) from Irradiance
Now we know that 3,000 milliwatts of photons are moving to the sq. cm. spot per minute.
That’s the rate of delivery, but how many photons did we deliver?
To make a dose, we need to know how many photons we’re delivering.
According to science, the best dosage is between 5 and 60 joules.
Joules are watts per second of photon energy.
We’re already in minutes, but we are still using milliwatts and not watts.
To convert from milliwatts to watts, divide the irradiance by 1,000.
3,000 mW/cm^2 at 6 inches per minute / 1,000 milliwatts per watt = 3 joules per minute
Are you still with me? We’re done.
We now know that 50 mW/cm^2 at our arbitrary-for-the-sake-of-example distance of 6 inches per second works out to 3 joules per minute at 6 inches.
Treatment Time Calculation Step 3: Derive Minutes per Session
Now we can calculate how many minutes of treatment it takes to get our target joules.
Let’s say you want to go for a 5-joules dose.
How many sets of 3 joules do you need to get 5 joules?
Divide the target joules by the joules per minute to get the treatment time.
- 5 joules target dose / 3 joules per minute = 1.67 minutes treatment time
- What is .67 of a minute?
- .67 of a minute x 60 seconds per minute = 40 seconds
The treatment time is 1 minute 40 seconds from 6 inches to deliver 5 joules.
Summary of Treatment Time Steps
- Irradiance per second: 50 mW/cm^2 at 6 inches
- Irradiance per minute: 50 mW/cm^2 at 6 inches x 60 seconds per minute = 3,000 mW/cm^2 per minute at 6 inches
- Joules: 3000 mW/cm^2 per minute at 6 inches/ 1,000 to convert milliwatts to watts = 3 joules per minute at 6 inches
- Joules Target Dose: 5J
- Treatment Time: 5 joules target / 3 joules per minute at 6 inches = 1.67 minutes
- .67 of a minute in seconds is .67 x 60 = 40.2 seconds
- Treat for 1 minute 40 seconds at 6 inches to get 5 joules.
Now throw that all out and use fluence to calculate treatment time.
Why Fluence Eats Irradiance for Breakfast
To start with a confession, it is true that Mito Red Light uses the same meter as their competitors to state irradiance.
If they use the wrong meter, don’t they severely overstate irradiance?
Yes, they do, and they say as much on their product pages.
The solar meter part is true. But don’t worry, I promise that Mito Red Light is the hero in this story.
On their product pages, Mito Red Light advises customers not to use irradiance to calculate dosing.
Here is the fluence, they say. Use this certified value that is not inflated to calculate treatment time.
I understand why Mito Red Light includes inflated irradiance values. They do it for the same reason almost all other vendors do it.
The average consumer would not understand the nuance that it’s taking me 3,000 words to explain to you.
The average consumer would never read an article like the one you’re reading right now.
The average consumer sees 50 mW and 150 mW and assumes that 150 mW is better. End of story. The average consumer buys 150 mW because it must be big, strong, and powerful.
Session time is inversely related to irradiance. A very large irradiance has a smaller session time. And inflated irradiance has an abnormally short session time that might not deliver enough photons to make any difference.
Inflated irradiance leads to a short session time that might not deliver a therapeutic photon dose.
But Mito Red Light also publishes product-certified fluence values for dosing. And just like that, dosing becomes easy, honest, and effective.
Fluence is all we need. With fluence, it’s crazy easy to calculate treatment time.
With fluence, we can rely on vendor values because there’s no pressure to inflate the numbers.
We can reliably calculate treatment times using fluence values.
How to Calculate Treatment Time Using Fluence
The MitoPRO takes 29 seconds longer than the MitoRED to deliver a 5-joules dose.
The MitoPRO takes 6 minutes and 2 seconds longer than the MitoRED to deliver a 60 joules dose.
The MitoRED MitoMEGA is faster than the MitoPRO 300.
A big device like the MitoMEGA has more bulbs to deliver more photons, so it’s going to deliver a faster session.
But the bigger point is that even if one device has a 2.2 fluence and another has a 2.8 fluence, the 2.8 fluence gives you a 6-minute faster session when you’re going for 60 joules.
When you go for fewer joules per session, the advantage starts to disappear. By the time you get to 5 joules, the more powerful MitoMEGA saves you a whole 29 seconds.
If you’re going to do lots of 60 joules sessions, then you’ll save a lot of 6-minute chunks getting the faster device.
But going for smaller doses, the amount of time saved is not that significant.
Conclusion
Fluence is a superior value to irradiance when calculating red light therapy treatment times.
Irradiance is usually inflated.
Vendors should display fluence per minute (but not per cm. sq.) and explicitly state the distance at which that fluence value is relevant.
There is very little difference between the treatment times of Mito’s least powerful and most powerful devices.
I would not use irradiance or fluence as a metric when deciding which Mito Red Light to buy unless I planned to do 40J, 50J, and 60J dosing on a regular basis.
