Just the Truth please

We’ve always aimed to carve out our own market niche. When a customer brought to our attention the article “Joovv Versus Sauna Space” at the Joovv company site, initially, we were flattered. Performing a simple google search will show the seemingly limitless number of light therapy and sauna options available to today’s savvy consumer. That Joovv chose to compare themselves to us, out of all the other products on the market, tells us that our unique approach to therapy has been rattling the right industry cages. We chose to take it as a mark of respect for our success.

However, upon reading Joovv’s specific claims in detail, we were surprised to find that their intentions were far from respectful. Many of the statements made to attack our brand were at best misinformed, if not deliberately misleading. That is why we’ve chosen to write our own article, in clear and concise terms, to put to rest the spurious arguments Joovv has chosen to use against us.

What SaunaSpace and Joovv have in common (and where we compete) is that we both make therapeutic solutions that utilize photobiomodulation. In order to differentiate themselves from SaunaSpace, Joovv has made the argument that our technology is inferior to theirs in providing this therapy. So, we’ll begin with an explanation of what exactly photobiomodulation is, so we can better understand the nature of Joovv’s claims, how they fail to be supported by scientific evidence and how Joovv’s distortion of the basic scientific facts speaks to their lack of professionalism.


Our Cells Love Full Spectrum Incandescent Light!

Photobiomodulation, or PBM, is a term from the field of photobiology, which studies the biological effects – both beneficial and harmful – of light wavelengths on living organisms. You may have heard of PBM referred to alternatively as: low-level light therapy, red light therapy, mitochondrial stimulation, mito-stim, or simply light therapy. Different names for the same thing.

PBM occurs when light photons are absorbed by living tissue, but not just any light will do. PBM is only possible within a certain wavelength range on the electromagnetic light spectrum: specifically from 600-1000 nanometers. This range is known as the ‘mitochondrial stimulation band’ (or ‘healing band’) because only these wavelengths of light stimulate the cellular mitochondrial light receptor enzyme, cytochrome-c oxidase. It thus encompasses both red light (600-700nm) and a portion of near infrared light (700-1500nm). When light from within this band of wavelengths is absorbed by the cells of the human body, the cell responds by increasing ATP production, releasing Nitrous Oxide, and forming Reactive Oxygen Species – all of which work to produce large-scale systemic benefits to the health of the body. Some, but not all, of the studied benefits of PBM are: promotion of anti-aging, enhancement of athletic performance, improvements in memory and cognition, accelerated muscle healing, and boosted cellular regeneration.

The utility of PBM as a non-invasive therapy with such a wide range of benefits is truly amazing. It’s no surprise, then, that there is a new and increasingly crowded market for personal photobiomodulation devices, all making unique claims to superiority. The question at the heart of this article and Joovv’s is this: which of these various light technologies are actually effective at providing PBM to consumers?


Ahh, the Synergy of the Natural Form…

SaunaSpace uses incandescent lamp technology. This is one of two main differences between ourselves and Joovv, who use panels of LEDs (Light Emitting Diodes). The crux of their argument against us is that incandescence is an ineffective method of providing PBM, especially in comparison to their LED panels. In support of this argument, Joovv repeatedly cites the research of Dr. Michael Hamblin. Dr. Hamblin is a renowned subject matter expert in PBM and has been named in countless PBM literature, review articles, and scientific studies. He also happens to be on Joovv’s scientific advisory board.

Here’s what Dr. Hamblin had to say in 2017 about the differences in quality between the various PBM light technologies:

Most of the early work in this field was carried out with various kinds of lasers, and it was thought that laser light had some special characteristics not possessed by light from other light sources such as sunlight, fluorescent or incandescent lamps and now LEDs. Howeverall the studies that have been done comparing lasers to equivalent light sources with similar wavelength and power density of their emission, have found essentially no difference between them [emphasis mine].” 1

To summarize, Dr. Hamblin is saying here that there is no difference between different sources of light (LED and incandescent, for instance) in terms of ability to provide PBM. Only two characteristics of light matter: wavelength and power density. As long as the light produced is within the recommended therapeutic ranges of both these variables, the source does not matter.

So let’s examine how SaunaSpace’s incandescent lamps measure up in these two categories, wavelength and power, compared to Joovv.


How do Incandescent Lamps compare LEDs in ability to deliver the correct wavelengths for PBM?


Not All Wavelengths Were Created Equal.

Joovv’s product line uses LED lights, which are monochromatic, a word derived from Ancient Greek, meaning “one color”. In modern physics, ‘monochromatic’ refers to light of a single wavelength or frequency. In context, this means that LEDs only emit light in very narrow wavelength bands. In terms of visual light, this means that a single LED can only produce light in one specific hue of a certain color. Contrast this to SaunaSpace, where we use incandescent bulbs to deliver PBM.

What is Incandescence?

Incandescence describes the phenomenon wherein an object, when heated to high enough temperatures, produces light — think of red-hot metal, coal, or the sun. Incandescence is decidedly not monochromatic in terms of the wavelengths of light that it produces. Our incandescent bulbs produce what we call full-spectrum light, in a wavelength emission curve that spans, with our bulb’s red filter from ~600 to over 4000 nanometers. To visualize, think about the example of the sun: the sun’s light gives us every shade of every color of the rainbow. The question becomes, which breadth of wavelengths is preferable to get the full benefits of PBM? In their article, Joovv points to scientific literature which asserts that PBM is effective exclusively within two mini-bands within the mitochondrial stimulation band spectrum: 630-670nm and 810-880nm. They further argue that there are little to no health benefits outside these two limited ranges. In making this claim, Joovv is effectively stating that all wavelengths outside of these two mini-bands are worthless for PBM. They use this line of reasoning to perform a calculation showing that only 3% of the energy of full-spectrum incandescent lamps lies within these two mini-bands, implying that the other 97% of the bulbs’ energy output is a waste. This is quite surprising in the context of defining the range or limits of the mitochondrial stimulation band, as Dr. Hamblin’s own research from 2017 concludes that PBM is achievable across the broader 600-1000nm range, and not just within the two limited parameters, or peaks, that Joovv cites in their study from 1996. Hamblin writes:
Many wavelengths in the red (600–700 nm) and near-infrared (NIR, 770–1200 nm) spectral regions have shown positive results… 2
Dr. Hamblin’s research shows that, in fact, PBM is achievable across the full 600-1200nm range. Mitochondrial stimulation PBM has been shown to occur strongly across the 600-1000 range.3

Did You Double-Check Your Math?

Joovv’s 3% calculation is wrong. When we calculate the percentage across the broader, 600-1000nm mito-stim band, we find that actually 14% of the energy emitted by an IR heat lamp activates mitochondrial functions (see calculation below). It’s also worth mentioning at this point that, unlike Joovv, SaunaSpace employs sauna heat therapy in addition to PBM, and that a full 74% of our bulbs’ wattage is used toward heating, meaning that almost all of the non-PBM energy is being used efficiently for our dual purpose. We’ll return to heat therapy more extensively later on. The 14% calculation shows our technology as having a substantially greater quantity of PBM, and furthermore, is actually up to date with the research from Joovv’s scientific advisor. However, this is not the only error Joovv’s made in their efforts to disparage us.

Sloppy Drawing, or Intentional Distortion?

A key piece of Joovv’s evidence in support of their claim for a narrow therapeutic PBM band is quite blatantly dishonest. In their article, they’ve reproduced a graph from one of Dr. Hamblin’s publications which shows that the ‘optical window’ (the band of light that can be absorbed by biological tissue) ends at 950 nm. However, if you look at the original graph from the Hamblin document they are citing, it’s clear that the original has been modified by Joovv. The original clearly shows the ‘optical window’ extending almost as far as 1400nm. In their reproduction, they’ve kept all other data and curves identical, but have greatly shortened the ‘optical window’ so that it ends at 950nm. This ‘error’ conveniently supports their case against our full-spectrum technology.
Dr. Hamblin’s Original Optical Window Figure 2 from his Mechanisms of Low Level Light Therapy Article. Original Optical Window Figure 2 from Dr Hamblin’s Mechanisms of Low Level Light Therapy Article. 4

Joovv brazenly misrepresents Dr. Hamblin’s Figure by halving the range of the Optical Window to support their weak arguments. Their misleading graphic has since been removed from their article…but, Joovv can’t hide from Google Cache.

The Basic Physics Calculation that 14% of Emission from our Incandescent Lamps Delivers PBM

We must integrate Planck’s Law across the wavelength band in question to calculate the energy emitted from an incandescent light source (called a black body radiator in physics). For those who are intimidated by physics and calculus, not to worry, there are many easy online calculators that do the tricky math for us! 1st calculate the TOTAL ENERGY emitted by our lamp by integrating Planck’s law across all wavelengths: CONSTANTS Temperature of Filament = 2450K Emissivity = 1 (we assume no light absorption by the glass bulb itself; real emissivity is perhaps slightly below 1, but almost 1) Recession velocity = 0 km/s (the light source is not moving away from us) Wavelength = 1 µm RESULT Therefore the radiance, or total energy emitted, = 650336 W/m2/sr across all wavelengths (0-10000nm) And then to calculate PBM ENERGY from our lamp that is in the 600-1000nm mitochondrial PBM band, we integrate from 600-1000nm: CONSTANTS Lower Limit = .6 µm (600 nm) Upper Limit = 1 µm (1000 nm) RESULT Band Radiance = 90763 W/m2/sr Finally, the PERCENTAGE OF PBM ENERGY OF TOTAL ENERGY from our lamps: 90763 / 650336 * 100% = 14% of the energy emitted by a 2450K red-filtered incandescent heat lamp is within the mitochondrial PBM band.

How Full Spectrum Incandescent Light Breaks Down into Light and Heat Therapy

Can I Get a Visual on That?

LEDs are all the rage now in the Biohacker and Light Therapy community right now, so it’s important to say that fads come and go quickly. LED Light Therapy is a fad, only a few decades old. Incandescent Light is as old as the universe and has nourished all life on Earth for millions of years. We’ve relied on the incandescent lamp to grow our food and heal our bodies for over 100 years. It is the closest mimicker of incandescent sunlight, of ALL man-made light technologies. Below is the ACTUAL emission spectrum of 250W our Incandescent Heat Lamp, referenced from Philips Brand. 5

Power Density:

Can Incandescent Lamps deliver enough Irradiance for Therapeutic-Grade PBM?


So… What is Irradiance?

Here’s an example: you’re driving down a remote country road at night. There’s no street lights, so you turn on your high-beams to see better. With your brights on, the road immediately in front of your car can be seen almost as clearly as during the daytime. But as you look further out, you can see the road less and less clearly until, at about 400 feet, you can no longer see cars or animals in the road any better than with your headlights off. This is because your headlights’ brightness decreases the further away it has to shine This effect of light decreasing in intensity the greater the distance is from its source is known as irradiance, and is the reason why it’s polite to switch off your brights if you get too close to a car driving in front of you. Irradiance is measured in terms of the amount of light power received by a surface, per unit area, in units of watts per square meter.

In context, irradiance takes into account the amount of light energy that a person will receive from a light therapy device at a given distance from the light source. Proper irradiance is key to proper PBM, once we’ve established that the light source is producing the right wavelengths of light, which we have at this point. Using the analogy of light as medicine, now that we know that we have the right type of pill (wavelength), it’s important that we’re taking the right dose (irradiance) for the medicine to be effective. In this case, the known dose for proper PBM with red wavelengths is between 10 mW/cm2 and 100 mW/cm2. Joovv’s argument, of course, is that we aren’t reaching even the minimum PBM dosage with our lamps, and are therefore, therapeutically useless.

Where things start to get interesting is when we look at what evidence Joovv uses to support this claim. They show photos of irradiance measurements they claim to have taken from our bulbs, which show pathetic PBM dosage. What’s funny is… those are NOT our bulbs!

Get the Bulb Wattage Right, Silly!

In Joovv’s photos [cite by number] they appear to use a 125 Watt bulb. What kind of bulbs does SaunaSpace use? 250 Watts! It’s a huge difference in power output. In the interest of science, we bought the same brand and model of device/reader Megger PVM210 Irradiance Meter 6 that Joovv uses in their article so that we could perform the same tests they did on our actual lamps. The PVM210 measures only 400-1100nm. There’s a minute quantity of 400-600 nm light exiting our glass bulb because it’s red-filtered, so the irradiance readings shown are approximately 100% PBM wavelengths. See our results below and compare them with Joovv’s.

Irradiance of our SaunaSpace Single Light Panel at 12, 18 & 24 Inch Distances

We measure ~15-34 mW/cm2 irradiance at the recommended usage distance of 12-18 inches from the single 250W lamp, well within the therapeutic photobiomodulation range of 10-100 mW/cm2.

As you can see, when you use the correct bulb, you get very different results at 12 inch, 18 inch, and 24 inch distances than those presented by Joovv in their piece. Correcting this major oversight makes the night-and-day difference between a smaller amount PBM output and a “therapeutic-grade” dose!

Another Joovv Sleight of Hand: The Myth of the 3%

Another seemingly misleading claim we should talk about is in the paragraph just below the Joovv bulb photo measurements. The sleight of hand here is somewhat difficult to parse unless you’ve been paying really close attention, so we’ll try to be thorough here. The Joovv article states below their irradiance measurements that “only about 3% of the energy is even effective for the activation of cytochrome c oxidase. So, as you can see, IR heat lamps are terribly inefficient for PBM therapy.”

What does this mean, exactly? Well, they are referencing the 3% calculation we addressed (and debunked) earlier, which claimed that 3% of our lamps’ TOTAL output (roughly 600-4000nm) was in the healing band of wavelengths. However, what the photos are showing are not measurements of our bulb’s total output. As we just established, the Megger PV210 Irradiance Meter only measures output in 400-1100 nm. What Joovv is implying by this phrasing is that only 3% of the irradiance meter reading is actually going to PBM.

So, in essence they are implying that only a small fraction of their already undervalued irradiance measurement actually applies to PBM, where in reality, virtually 100% of the wavelengths measured by the meter are PBM active and the 3% calculation is totally irrelevant.

This is just one more in the list of misleading claims by Joovv. But wait, there’s more…

Number of Bulbs? They Count 1, But I See 4…

If we take a charitable reading of Joovv’s power measurements and consider the use of a lower wattage bulb to be an understandable oversight, then this next error is positively reckless in its lack of scientific rigor.

Joovv may not be able to determine what wattage of bulbs we use just from looking at our product photos (although it’s listed throughout our website with a bare minimum of research), it should be obvious to anyone who’s even seen a photo of our product that the SaunaSpace Pocket Sauna’s 4 Light Panel uses FOUR such 250 Watt bulbs, not just one.

With four of our bulbs clustered together in our Pocket Sauna’s Light Panel, you get four times the heat, light, and and more than 4x the irradiance as just the one 250W bulb.

It strains the boundaries of belief that Joovv was unaware of this simple fact before diving in to their exhaustively researched piece.

Irradiance of Our 4 Light Panel (1000W Total) at 12, 18 & 24 Inch Distances

We measure ~30-67 mW/cm2 irradiance at the recommended usage distance of 18-24 inches from the 4 250W lamps, landing firmly within the therapeutic photobiomodulation range of 10-100 mW/cm2.

Take a look at the irradiance measurements of the fully operational Pocket Sauna, delivering a very healthy dosage of PBM. That’s right, contrary to everything Joovv has said so far, SaunaSpace manages to fulfill both of Dr. Hamblin’s requirements of wavelength and power, proving that we are PBM device to be taken seriously.

What about this claim that Professional Saunas use only Far Infrared Emitters?

Joovv seems to understand little about Infrared Light…and even less about saunas.


It’s All About the Water Absorption.

Having fully rebutted Joovv’s case that our incandescent lamps fail to deliver a minimum of photobiomodulation, we’d like to address their final insult. After having proven in their own minds that our product is a “poor source of light for the purposes of photobiomodulation”, and thus not a fitting competitor in that field, they go the extra mile out of their way to say that we are a poor sauna product as well.

Their reasoning behind this allegation is that our lamps don’t produce as much ambient heat as a far-infrared emitter. This is actually true. The Pocket Sauna (inside air temperature ~110-125°F) doesn’t get as hot as a far-infrared (inside air temperature ~150°F) or traditional steam sauna (inside air temperature ~110-125°F). This is because it doesn’t have to. The benefits of sauna therapy don’t come from raising the temperature of the air. They come from raising the core temperature of the body. Granted, one way to accomplish raising body temperature is by remaining in a hot enough environment for an extended period of time.

How our incandescent sauna works instead is by heating the body radiantly, from within.

Water absorbs different wavelengths of light to varying degrees. We see below in the Water Absorption Spectrum that near infrared wavelengths consistently penetrate tissue 2-3 orders of magnitude deeper than far infrared wavelengths will ever penetrate.

This graph above was built using data points from the above referenced Wikipedia article. Further confirmation that near infrared is a more efficient, effective means of heating biological tissue than far-infrared wavelengths can be seen below in this old Philips Incandescent Heat Lamp Data Sheet showing Tissue Penetration of Wavelengths. 7

Farmers have understood this for over 100 years. Far-Infrared Emitter Sauna Manufacturers Still Don’t Get It!

This is why near infrared wavelengths deliver radiant, penetrating tissue heating. Near infrared wavelengths heat our bodies up much more efficiently than far infrared. Far infrared wavelengths, because they exhibit very shallow penetration into tissue, deliver less effective conductive surface-heating.

The beauty of having a incandescent full-spectrum sauna is that you get the spectrally natural form of infrared, which means primarily Near Infrared Light, and the Synergy of Photobiomodulation and Heat Detoxification.

Joovv’s LEDs will never be as good as SaunaSpace Incandescence, Period.
Once again, Joovv has shown themselves to utilize the artifice of science and data to disparage our brand while ignoring the fundamental scientific principle of being self-critical. If they plan on smearing any of their industry peers in the future, we suggest they first take their own advice to heart: “make sure you understand the science before making any decisions.”

But, really, how much intellectual rigor can be expected from an LED company that uses an incandescent light bulb as their logo?

But Wait, There’s More…

SaunaSpace Delivers More Light Therapy, without Flicker Stress or EMF Stress.


Other considerations if you are looking to buy a Device for Light Therapy (even if you don’t care about all the amazing benefits of heating the tissues).

If you’re interested in investing in a PBM therapy device and are deciding between SaunaSpace and an LED device, we’ve provided side-by-side comparisons across a few different metrics to help inform your purchase: PBM Irradiance, Flicker Stress Test and EMF Stress Test.

Can you guess who wins?

Joovv claims their product delivers over 100 mW/cm2. Curious that they do not support this photographically. We got our hands on their Original Combo Device and measured it using the Megger PVM210, and the results may surprise you: SaunaSpace delivers ~20-50% more irradiance than Joovv at the same distance.

Full Disclosure: We measured irradiance on both devices using the Megger PVM210.8

92.0 mW/cm2 @ 12 inches

67.2 mW/cm2 @ 18 inches

30.0 mW/cm2 @ 24 inches


44.5 mW/cm2 @ 12 inches

31.8 mW/cm2 @ 18 inches

23.1 mW/cm2 @ 24 inches


Rapidly flickering light has been shown now in numerous studies to be a damaging nervous system stressor. Even we can’t really see it with the naked, it adversely affects our body’s cells and nervous system. It’s been shown to cause migraines, excessive sympathetic dominance, and many other serious health problems.


SaunaSpace incandescent heat lamps DON’T flicker because they produce light via naturally their tungsten filament that glows!


You definitely don’t want flickering light to counteract your photobiomodulation therapy.

Unfortunately, LED devices like those of Joovv flicker at 120 Hz, or 120 times per second!


SaunaSpace understands the serious problem of EMF stress: man-made magnetic and electric fields have been shown in many studies to be nervous system stressors. You definitely don’t want EMF stress coming from your PMB device!

SaunaSpace design solutions ensure our products exert ZERO EMF influence on the body when used as directed. That means ZERO electric field stress and ZERO magnetic field stress.

Joovv claims their product delivers “no EMFs at the recommended treatment distance.” Hmm…the Joovv Original Combo Device we tested FAILED to meet that claim. The Joovv device we received by ordering from their online website DIDN’T even come with a shielded power cord!

Full Disclosure: the following electric field measurements were made using the Geovitals EM Field Probe. 9 This incredibly sensitive electric and magnetic field meter utilizes specialized gold-plated sensors; it’s by far the most sensitive consumer electric field meter available.

Geovitals, the world-renowned Austrian Academy for Radiation Protection and Environmental Medicine, is known for setting the most stringent EMF shielding standards on earth. They recommend that any electric field reading above 30 V/m is a serious problem. Ideally we want 0 V/m. To put it simply, ideally we don’t want any part of our body to be in a space or on a surface that measures above 0 V/m.


Our Faraday Lamp Guards shield the user from electric fields that are emitted by the incandescent lamp, even at 0 inches from the lamp.


Our Leading Edge Shielding Design means there is 0 electric field emission from the Light Panel Body and also none from the Power Cord.

We will only ever be satisfied with 100% Shielding.


No matter how close you are to our Light Panels, they exert 0 electric field stress on your body.

At the SaunaSpace recommended use distance of 12-24 inches from the Single Light Panel, you don’t get any EMF from our product.

Same goes for our 4 Light Panel, no EMF from it on the body at 12 inches, much less at the 4 Light Panel’s recommended 18-24 inch use distance.

Ahh, no EMF feels good!


Don’t touch the Joovv when it’s turned on or you’ll have thousands of volts per meter of E-fields coursing through your body.

Ouch, that’s a lot of EMF!


Electric fields are sneaky; they constantly seek out destinations of lower electrical potential. The tiniest fraction of moisture in materials like carpet, or even the air, give E-fields a path to your body.

All electrical devices we use ought to have shielded power cords. Alas, most don’t…and neither does the Joovv.


Again, Joovv claims to deliver “no EMFs at the recommended treatment distance.”
They recommend using their LED device at a range of 6-12 inches.

Unfortunately, you are definitely receiving an undesirable 11-43 V/m of E-field stress at this usage range.
In other words, even without touching the Joovv device, it is stressing you out with EMFs during the entirety of your “therapy” session.

Light Therapy Buyer’s Guide Conclusion

SaunaSpace Delivers More Bang for Your Buck, and More Value for Vour Time.

Why Settle for Joovv’s Synthetic, Lab-Made Vitamin C Powder when SaunaSpace gives you the Orange? Go with SaunaSpace Incandescence: the Smart, Ancestral Choice.
  1. Hamblin M. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophysics.4(3): 337-361. (May 2017); DOI: 10.3934/biophy.2017.3.337.
  2. Hamblin M. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophysics.4(3): 337-361. (May 2017); DOI: 10.3934/biophy.2017.3.337.
  3. Hamblin M, Demidova T. Mechanisms of low level light therapy. Proc. SPIE 6140, Mechanisms for Low-Light Therapy. 614001 (Feb 2006); doi:10.1117/12.646294.
  4. Hamblin M, Demidova T. Mechanisms of low level light therapyProc. SPIE 6140, Mechanisms for Low-Light Therapy. 614001 (Feb 2006); doi:10.1117/12.646294.
  5. Philips. R125 Incandescent Reflector Data Sheet.
  6. The Megger PVM210 Irradiance Meter
  7. Philips. R125 Incandescent Reflector Data Sheet Showing Tissue Penetration Depth of Wavelengths.
  8. The Megger PVM210 Irradiance Meter
  9. The GeoVitals EM Field Probe