Written by Christopher Ioannou, BSc (Hons) Sports & Exercise Science

Reading Time: 16 minutes

Table of contents

• Five Features Red Light Therapy Devices Should Have

  • Emitted Light Frequency

  • Power Density or Irradiance

  • Dosage

  • Treatment Coverage

  • Electromagnetic Field Levels

• Quick Recap

• Personal Positive Feedback

• Personal Negative Feedback

• Summary

The video version of this post:

Today we are going to review two Joovv Red Light Therapy devices: Joov Go and Joov Mini.

We will cover the five features red light therapy devices should have, according to our own review of the photobiomodulation literature.

As we go along we’ll also compare those points to the Joovv devices to see if they meet the scientific standards – and give our own personal feedback on our experience of both the Joovv devices and the company itself.

For those of you who are unaware of how red light therapy works and the proven scientific health benefits of photobiomodulation, you can check out this video.

Alright, let’s get started with the review. We’ll cover one point at a time. As I just mentioned, there are five key characteristics that good photobiomodulation devices must have.

According to the scientific literature, light frequencies, one in the red spectrum at 660nm and one in the near infrared spectrum at 850nm (Figure 1), have been tried and tested in many scientific studies and have been proven to have great photobiomodulatory effects on the body [21].

Red light has been used to help with inflammation, wound healing, the production of stem cells, skin rejuvenation, hair growth, acne and fat loss, among others [15].

The therapeutic benefit of near infrared light has been demonstrated to include cellular growth, inflammation, connective tissue healing, protein synthesis, bone remodelling, stem cell activity, muscle recovery, pain relief and many more [4][15].

Now, it’s important to mention that our cells respond in pretty much the same way to both of these light frequencies. The only difference is penetration depth.

Red light is absorbed by the top layers of the skin and elicits a response in those cells, while near-infrared light penetrates through all the layers of the skin and gets absorbed by the underlying tissue, muscle and even bone (Figure 2).

In dermatology, for example, a study was conducted in which it was found that near infrared light had the greatest effect on skin elasticity, while red light improved pigmentation and overall skin tone.

However, the authors of the paper concluded that the best results could be attained by using a combination of these two wavelengths [3].

For this reason, Joovv has combined these two light frequencies in nearly all its devices (Figure 3). This means that you get the best of both frequencies; one band can be switched on independently during treatment, or you can use them simultaneously.

The only exception is the Joovv Go travelling devices - they have only one band each. So, deciding which travelling device to choose would depend purely on what tissue you are trying to treat.

You would want the red light one for more superficial tissues, particularly the skin, or the near infrared one to treat deeper layers, such as muscles, joints and the brain.

Obviously, as I explained earlier, all Joovv’s other devices, like the Joovv Mini that we also tested, contain both light bands, so you don't have to worry about choice if you opt for those units.

Power Density or Irradiance, refers to the number of photons of light (or packets of light energy) that hit a specific area at a given time [1]. It’s like the intensity of the light and it’s measured in mW/cm².

Over and above the wavelength used, it is this intensity or power density that determines whether the light is capable of penetrating deep enough and imparting adequate amounts of energy to stimulate or activate the cells at the required depth [1][19]. 

A device that is not powerful enough might require an uber-long exposure time to get the right dose. Moreover, insufficient power could also compromise the penetration depth and overall effectiveness of the treatment [4].

On the other hand, a device that is too powerful could heat up the exposed cells too much, and thereby traumatise them to the point that they respond negatively [4][15][19].

So, having the correct light intensity is key [4].

According to the leading researchers in the field of photobiomodulation, the power density or ‘intensity’ of red and near-infrared light should be between 1 and 100mW/cm2 to have a therapeutic benefit for the exposed cells, as well as being on the safe side [1][4][15][18][19]. However, the authors of a literature review on home-use devices found that a range of 14-55 mW/cm² was used in studies that reported beneficial results [21].

To test this out, I used my Irradiance Meter (US Store ; UK/EU Store) to check the power of the Joovv light from both their battery-powered travelling units as well as their larger panel (Figure 5).

Results:

Battery-powered devices:
Near Infrared Ligth: at a 10, 20 and 30cm exposure distance, the measurements were 55, 40 and 27 mW/cm² respectively.
Red Light: at a 10, 20 and 30cm exposure distance, the measurements were 40, 28 and 17 mW/cm² respectively.

Wall-powered Joovv Mini panel:
Near Infrared Ligth: at a 10, 20 and 30cm exposure distance, the measurements were 73, 59 and 52 mW/cm² respectively.
Red Light: at a 10, 20 and 30cm exposure distance, the measurements were 55, 45 and 40 mW/cm² respectively.

Comparatively, the Joovv Mini was about 25% more powerful than the Joovv Go travelling devices. So, what does that mean in terms of effectiveness?

Well, it means that, with the Joovv Mini, I can stand further away from the device and still get the same dose of light per cm² (Figure 6). The advantage of standing further away is that, due to the angle of the emitted light, more surface area of the skin can be exposed during a single session, which increases the total dose of light received by the body.

However, if you are targeting only specific tissue, such as the face, this doesn’t really matter.

Nevertheless, these recordings show that both versions of the Joovv devices comfortably emit a light intensity that is within the range recommended by the academic photobiomodulation literature. That means they are powerful enough to penetrate through the skin and into the targeted tissue, but not so powerful that they can damage your skin or skin cells.

All the Joov devices can be purchased through their website. Use voucher code EH to get a free gift with every purchase.

Receiving the correct dose of red and near infrared light per square cm of body tissue is the next feature of successful photobiomodulation therapy.

We call this metric “energy density”, which refers to the amount of light energy that has been delivered to the cells per unit area in a given timeframe. Energy density is measured in J/cm² [1].

Scientific studies on home-use devices indicate that doses of 4-50 J/cm² per treatment yield positive results. The only study in which a positive outcome was not found was one in which the researchers used more than 50 J/cm² in a single treatment.

This is because high doses have been shown to cause too much stress to the cells, to the point where they can become damaged [15].

Remember, a little stress on our cells is often a good thing, but, of course, overdoing it is never the way to go – in the same way that regular doses of exercise put beneficial stress on the body, stimulating it to get fitter, stronger and ready for the next bout of training, but we can also damage our bodies if we do too much exercise in one go.

So, spending more time in front of these lights, hoping that a bigger dose will generate better results, does not apply with red light therapy [1][18]. Because photobiomodulation doesn’t yield immediate tangible results, there is sometimes a tendency to think that longer exposures are needed. However, photo-activated cells take days to weeks of regular doses to show significant changes. So just bear that in mind.

Anyway, with that important message out of the way, let’s calculate what doses the Joovv devices provide per cm² in their recommended treatment time of 10 min (Figure 8).

To calculate this, you take:
[ Intensity of Light (in mW/cm²) ✖️ Duration in Seconds (10 minutes = 600 seconds) ] ➗ 1000. The answer is given in Joules/cm².

Results:

Battery-powered devices:
Near Infrared Ligth: at a 10, 20 and 30cm exposure distance, the measurements were 33, 24 and 16.2 J/cm² respectively.
Red Light: at a 10, 20 and 30cm exposure distance, the measurements were 24, 16.8 and 10.2 J/cm² respectively.

Wall-powered Joovv Mini panel:
Near Infrared Ligth: at a 10, 20 and 30cm exposure distance, the measurements were 43.8, 35.4 and 32.2 J/cm² respectively.
Red Light: at a 10, 20 and 30cm exposure distance, the measurements were 33, 27 and 24 J/cm² respectively.

As you can see, 10 minutes with the Joovv devices at a 10-30cm exposure distance cannot overdose our cells with light. These readings also sit comfortably within the scientifically-proven effective dose of 4-50 J/cm2 found for home use devices [21].

Now, it is important to mention that, within this pretty broad range, depending on what you are trying to achieve from red light therapy, whether it be skin rejuvenation, muscle recovery, wound healing, sleep, or any of the other benefits of photobiomodulation, each therapeutic benefit, according to the research, requires a different exposure distance and treatment duration.

Treatment coverage refers to how much of the body is exposed to red light during the therapy. Some treatments that target the skin on the face, the brain or a specific injury might not need a lot of coverage.

However, more systemic treatments, such as enhancing overall ATP energy production, improving sleep, stimulating weight-loss, or speeding up muscular recovery require that a larger percentage of the body is exposed to this light for optimal results.

So, this is how Joovv has set out to accommodate these diverse needs. The company produces a wide range of red light devices, ranging from battery-powered travel devices, such as the ones we have been testing, to full body panels meant to target the entire body.

What makes Joovv’s product line unique is that its larger panels have a patented modular design that enables you to slowly build your full body red light therapy device over time (Figure 10).

So, for example, let’s say that you can’t afford the thousands it would cost for a full body panel.

You could buy a single panel, such as the Joovv Mini we tested, which is great as a standalone device, but then a few months later buy another one to upgrade the system to a half panel.

This process can be repeated until you have a full body setup, without having to spend all the money upfront.

Each one of these devices seamlessly fits into the others like a puzzle, making upgrading your home setup super easy.

The 5th and final characteristic that photobiomodulation devices must have is low electromagnetic field levels.

In this day and age we are inundated with electromagnetic waves due to our dependence on tech.

Recently, for example, the upcoming 5G network infrastructure has created a lot of hoo-ha because of the potential health risks involved from daily exposure to these radio-waves.

So, when you are trying to benefit from a treatment protocol such as red light therapy, it would be counterproductive to blast yourself with high levels of unhealthy electromagnetic field levels at the same time.

So, with our handy Electromagnetic Field Meter (US Store ; UK/EU Store), let’s compare the readings we got from the Joovv Go, Joovv Mini, a Computer Monitor and an LED Studio Light, at a pretty normal exposure distance of 15cm (Figure 12).

Results:

Battery-powered devices:
Ambient Readings: ± 34 V/m
Device Readings: ± 35 V/m

Battery-powered devices:
Ambient Readings: ± 34 V/m
Device Readings: ± 40 V/m

Computer Monitor:
Ambient Readings: ± 38 V/m
Device Readings: ± 600 V/m

LED Studio Lights:
Ambient Readings: ± 50 V/m
Device Readings: ± 500 V/m

According to the company, the reason for the low electromagnetic field emittance from their products is due to a protective barrier they have fitted around the wiring on all their components. So, a big thumbs up to Joovv on what they have done with electromagnetic fields.

1. Joovv devices emit tried and tested light frequencies of 660 and 850nm.

2. Their light intensity or power density is strong enough to provide a photobiomodulatory benefit to the body, but not strong enough to damage the skin.

3. 10 minutes in front of a Joovv device can provide a sufficient light dose to achieve a therapeutic effect.

4. Joovv’s broad range of travel and modular devices can provide targeted to full body coverage.

5. Joovv devices emit low electromagnetic fields, making them safe for daily use.

The Joovv Go and Mini devices we have been testing are extremely well made. You can tell that this is not Joovv’s first rodeo. The metal construction gives a nice weight to the product and makes it feel premium.

The travelling devices weigh in at 582g each, so chucking them into your hand luggage shouldn’t be an issue. The carrying cases are hardy and will definitely protect your device while carting it around.

Each device comes with a high-powered charging brick and thick hardwearing type-c cables, which charge them up pretty quickly.

The batteries tend to last a few days with morning and evening sessions of 10 minutes each. Obviously there is no need to worry about charging Joovv’s larger panels, like the Mini, because they are powered straight from your wall plug.

I got the metal stand for the Mini, which allowed me to set it up on a shelf in my room. While this panel is not as portable as the Go, having it conveniently set up in my room serves as a daily reminder to use it.

‘Joovving’, as many call it, has now become part of my morning routine.

I have also found that 10 minutes in front of the light after waking up has given me an opportunity to think about and plan the day ahead.

So, I’ve felt nice and energised, as well as mentally prepared for the day after each session.

This has been an unexpected benefit I have found from adding red light therapy into my morning routine - If I travel, I can maintain this morning ritual by taking the Go devices with me, which is cool.

These red and near-infrared lights are pretty powerful and bright. It is therefore recommended to wear safety goggles, or at least keep your eyes closed when exposing your face.

The risk here involves the retina of the eye, in which light is concentrated after entering into the pupil [1].

As you can see in Figure 15, a 590mW/cm2-intensive light source entering the eye is amplified six times by the time it reaches the retina [1].

With daily exposure of many minutes, it is unknown what damage might be done if the correct precautions are not taken.

It might also be necessary to avoid switching the device on in a dark room. Our pupils dilate to more than double their usual size in the dark in order to allow extra light to enter.

So, switching on a bright and powerful photobiomodulation device in a dark room could send huge amounts of light into the eyes and potentially damage them [20].

This issue might be especially relevant with near-infrared light, which cannot be seen, yet still emits intensive energy.

In this case, we cannot rely on our blink reflex to close and protect the eyes if the source is too bright [20]. So, again, closed eyes or the use of protective goggles is definitely the safer route to take here.

Now, many other companies provide protective eye goggles with their devices, but Joovv does not - click here (US) or here (EU & UK) to get some.

When it comes to price, Joovv devices are not cheap. They are among the more expensive home-use red light devices on the market. I won’t mention exact prices, because they are subject to change over time, but you can click here to learn more.

The company claims that the premium price is due to the quality of the materials it uses in the construction of its products, as well as the research and development that goes into designing them. Joovv backs up these claims with a two-year warranty, which is nice. However, the two-year warranty is valid only for their larger panels, like the Mini. The Joovv Go travel devices come with only a one-year warranty. I guess this is to be expected, because the risk of breaking them while travelling is obviously higher.

The Joovv website is an amazing resource for education on red light therapy. All its articles are referenced with a large body of research and they are very easy to understand. I’m glad to see that the company has put a large chunk of time into educating people about the science of photobiomodulation.

Finally, I’m glad to see that Joovv devices are Class II FDA certified. This means that they are not classed as medical devices, but are indicated for the relief of muscle spasms, minor muscle and joint aches, as well as pain and stiffness associated with arthritis. So, having at least some approval from the FDA gives me more confidence in their products.

Let’s do a quick recap on my personal experience with Joovv:

1. Its devices are well constructed and robust.

2. I like the portability of the Joovv Go travel devices and the fact that I can maintain my morning routine on the road.

3. Their panels are expensive, but the wide range of options and ability to build up my setup over time with their modular design makes the price less intimidating. The two-year warranty helps in this regard. However, I was sad to see that the Go range gets only one year.

4. It was an inconvenience to have to buy protective eye goggles, but I have found that closing my eyes seems to do the job too

5. The Joovv website has a rich source of scientifically-backed photobiomodulation research.

6. Joovv is a company that is not scared of getting its devices tested by third parties, which gives me a level of confidence in the products it produces.

All-in-all, Joovv is one of the leaders in the red light therapy for home use space. The company has been producing these devices since 2015 and is currently in its second generation of products. I am looking forward to seeing what the Joovv team will produce next and how they will continue to innovate in this space.

If you want to grab yourself a Joovv device, the company has offered our audience a $50 discount with every purchase* using code EH on checkout on their website.

If you have any questions, feel free to reach out on the comments section below, on our Youtube, or via DM on Instagram.

Until next time, keep on exercising your health - Cheers!

*Excluding the Joovv Go 2.0 device.