Choosing the Most Effective Red Light Therapy Bulbs
Although they share the word “light” in common, not all lighting technology is the same. If you’ve considered investing in a red light device for use at home, it’s important to understand the difference between the various types of bulbs. This sort of knowledge can help you choose the most effective red light bulbs to get the results you want.
Before we delve too deeply into bulb types, we’ll review some general information about what red light therapy is, how it works, and how it can benefit you. This will shed some light on why certain types of bulbs outperform the rest.
Red Light Therapy Basics
Red light therapy (RLT) is known by several different names, including photobiomodulation, low-level light therapy, low-intensity light therapy, and infrared light therapy. It is based on the age-old practice of sun therapy but without the risky side-effects of prolonged exposure to harmful ultraviolet (UV) rays.
Unlike sunlight, red light is safe and free from side-effects. As Michael Hamblin, who is an associate professor at Harvard Medical School and a noted expert on red light therapy, stated during an interview: “You could use RLT for 24 hours a day and wouldn’t damage the skin. It’s almost impossible to cause any harm.”
The name “red light therapy” is often used as an umbrella term that refers to both red light and near-infrared (NIR) light wavelengths. The only difference between them is the size of their wavelengths; the longer the wavelength, the deeper it penetrates the skin. These wavelengths are measured in nanometers (nm), with red light ranging from 630nm to 660nm, and NIR ranging from 810nm to 850nm.
A great deal of research has been done on the unique properties of each wavelength of light. Green light, for example, has a calming, soothing effect, and has proved to be effective at treating migraines, while blue light is energizing. Research has shown that overall, the most beneficial wavelengths are red light and NIR light, which fall into the “therapeutic window” of light that is good for humans without being harmful.
Here’s how red light therapy works. When you feel the warmth of sunlight on your skin, you’re really feeling ultraviolet wavelengths, which are invisible to the human eye and perceived as heat. But the visible wavelengths of sunlight—specifically, red and NIR wavelengths—are perceived as light, rather than heat.
Red light therapy devices deliver red/NIR wavelengths to bare skin. As light photons penetrate the skin, they are absorbed by mitochondria (energy centers of cells), which in turn step up the production of cellular fuel. This stimulates biological processes that lead to a positive ripple effect of benefits throughout the body.
Red light therapy has been proven effective for treating an immense array of conditions and disorders, including skin problems, wounds and muscle tears, chronic pain, hair loss, and even neurodegenerative brain disorders. Thousands of studies and clinical trials conducted over the past several decades confirm its effectiveness.
One of red light therapy’s most widely known benefits is its ability to heal inflammation. This has been revealed in numerous studies, including dozens by Hamblin. In his May 2017 study, Hamblin explains that “low-level level laser therapy is the use of red and near-infrared light to stimulate healing, relieve pain, and reduce inflammation.”
According to Rhonda Klein, M.D, a board-certified dermatologist in Westport, Connecticut, red light therapy boosts circulation, which brings “more oxygen and nutrients to your cells and tissues.” In addition, says Klein, red light stimulates the production of collagen and elastin, as well as fibroblasts, which are cells in connective tissue that produce collagen and other fibers.
If you’re interested in learning more about red light therapy’s health benefits, visit the PlatinumLED blog, where you’ll find many articles about it.
All Light Technology Is Not the Same
When people hear about the immense health benefits of red light therapy, they’re often motivated to start using it right away. That’s wonderful—but it’s important to know that merely shining a bulb that emits red and/or NIR light on the skin isn’t enough.
If the light source is weak or the light is too diffused, not enough light photons will absorb into the skin. You could mitigate the weak light output to some extent by prolonging your treatment sessions, but you would still not achieve optimal results with light that is too weak. Why?
It goes back to what we said earlier about the depth of wavelengths. Red light wavelengths (630nm to 660nm) absorb about 3mm (0.11 inch) into the skin. NIR light wavelengths (810nm to 850nm) absorb about 10mm (0.39 inch) into the skin and underlying soft tissue, as well as through connective tissue and bone.
The light that enters the skin needs a direct path to the skin, and enough energy behind it to help "push" the light as deep into the skin as possible.
Diffused light has a much harder time absorbing into the skin than direct beams of light, no matter what the bulb's wattage is. What you want is more light, "pushed" with greater power.
How Do Red Light Therapy Bulbs Differ?
If you have read that red light therapy can be delivered using any type of bulb, including incandescent, fluorescent, halogen, or light-emitting diode (LED), you’ve unfortunately been misinformed. The fact is, all light technologies are not the same, and some are not suitable for light therapy at all.
Incandescent and Halogen
Incandescent lights heat a tungsten filament to a high temperature to produce visible light and (mostly) infrared radiation.
Halogen is a type of incandescent bulb in which the tungsten filament is encased in a narrow tube filled with a halogen substance (iodine or bromine), as well as an inert gas. This allows the filament to heat to higher temperatures than standard incandescent bulbs and extend their lifespan.
Incandescent and halogen technologies are inefficient for use in red light therapy, as well as potentially dangerous.
- With incandescent bulbs, 90% of the energy generated is lost as heat; only 10% converts to light.
- With halogen bulbs, 80% of the energy generated is lost as heat; only 20% converts to light.
- The light that emanates from incandescent and halogen lights is diffused. It emanates 360 degrees from the filaments so most of the light energy isn’t even directed toward the skin. Even if it's reflected or directed, the light loses energy as it travels, so very few light photons can be absorbed effectively.
- Incandescent and halogen lights aren't durable (they shatter easily) and only last up to 1,200 hours and 2,000 hours respectively.
- The ultraviolet radiation generated by incandescent and halogen lights can damage cells rather than supporting them.
Neither incandescent nor halogen lights can deliver specific red and/or NIR wavelengths.
Incandescent and halogen bulbs are on what’s known as a “continuous spectrum of light,” which ranges from 300nm to 1400nm. We don’t see these wavelengths as they truly exist—as separate colors. Rather, we see them collectively and perceive the wavelengths as warm, white light.
There is no way to adjust or “fine-tune” incandescent or halogen lights to the beneficial red/NIR wavelengths. While tinted red glass is sometimes used, this is done for special effects only and not for therapeutic effects. Red bulbs only allow red wavelengths to filter through, but they still incandescent and deliver only diffused weak light energy output. We’ll review this more in-depth in a moment.
You may have seen fluorescent red light devices and beds in gyms, facial salons, tanning salons, and online. Fluorescent bulbs are sometimes used because they are cheap. But, they are also ineffective for therapeutic uses.
Fluorescent lights work by electrically charging mercury gas. The electric current in the gas excites mercury vapor, which produces ultraviolet light that, in turn, causes a coating on the inside of the lamp to glow. The telltale sign that you’re looking at a fluorescent light bulb is that it’s shaped like a tube (whether straight or coiled).
Fluorescent bulbs are cheap and don't generate the heat or UV radiation of incandescent or halogen lights, but there are many downsides to fluorescent technology, especially as it relates to red light therapy.
- Fluorescent lights contain toxic mercury, so when they fail, they must be taken to a safe-disposal facility and not mixed with the regular trash.
- The bulbs only last up to 15,000 hours. If a manufacturer talks about bulb replacement, it's most likely a fluorescent light since LEDs last indefinitely.
- The main annoying characteristic of fluorescent lights is that they age. The light becomes dimmer over time and requires increasingly more energy to operate. The dimmer the light, the weaker the light energy output.
- The light is diffused 360 degrees in all directions, which means only a tiny fraction of the energy is delivered to the skin, and the rest is wasted.
- Fluorescent lights can't be "fine-tuned" to red/NIR wavelengths; they are available as warm white, cool white, or full-spectrum, which mimics the spectrum and color temperature of daylight. In any configuration, you won’t get the specific red/NIR wavelengths that are most beneficial.
- Even when fluorescent light is reflected/redirected to shine on the skin and the bulbs are tinted red, the light is still diffused (omnidirectional). So, what little light reaches the skin isn’t strong enough to effectively absorb into the skin.
An Overview of LED Bulbs
Light-emitting diode technology has been around since the 1960s. In the late 1980s, NASA’s research into growing plants in space was so promising that it led to the use of LEDs for stimulating astronaut health. This, in turn, sparked a huge body of research into LED light therapy for general human wellness.
In general, LED lights have significant advantages over other types of bulbs, for general use and red light therapy.
- Tight wavelength span: LEDs can deliver specific wavelengths within the therapeutic range of 630nm to 660nm (red light) and 810nm to 850nm (NIR light).
- Compact bulb: The small size of LEDs means that more can be grouped in a compact area; the more bulbs there are, the more light energy will be absorbed into the treated area.
- Long-lasting: LEDs can have lifespans of 100,000 hours or 11.4 years—and that’s if the lights were left on 24 hours a day, seven days a week.
- Very little heat: Only 10 to 20% of the energy created by LEDs is emitted as heat, which makes the technology safer, extends the device's lifespan and makes for a pleasant therapy experience.
- Less energy cost: LED bulbs are extremely energy-efficient. They deliver the most lumens per watt, meaning that less energy is required for them to release superior light energy output over other types of bulbs.
- Directional light (90 degrees vs. 360 degrees) means less need to reflect or redirect the light, and more light energy is aimed exactly where it is needed.
- Safe: LED bulbs are shatterproof.
- No replacement and virtually no maintenance, just light cleaning of the surface.
- Depending on the semiconductor materials used, LEDs can generate the entire spectrum of visible light or specific wavelengths, without using color filters.
- LED bulbs contain no mercury, toxins, or dangerous gases.
The only real drawback to LED bulbs is that the upfront cost is relatively high compared to other light technologies. But when you consider the benefits and longevity, the lifetime cost is very low.
Only One Light Works for Red Light Therapy: LEDs
Now that we’ve reviewed the three main types of bulbs you’ll see in lights, and even some therapy lamps, let’s review which is best for light therapy. The answer is LEDs—and it’s not a close competition. Fluorescent and halogen lights do not work for light therapy at all. Why? They can’t produce the right wavelengths.
When you use LEDs, you can adjust each bulb to only emit a specific wavelength of light. You do this by changing the construction of the bulb at the source of the light: the built-in semiconductors. Each semiconductor lets off light based on a number of factors including the material used, amount of energy applied, built-in controls, and more. This is important because it allows you to control the light so it’s a specific color or wavelength the moment it’s created.
Halogen and fluorescent bulbs, on the other hand, can not control wavelengths with any manner of precision. Instead, to change colors you simply apply a colored film or paint to the outside of the bulb. Then, the light will appear to change color as it moves through the film.
This method of changing the light color using films or paints is cost-effective, but it doesn’t work for light therapy. Light therapy requires very the use of specific wavelengths to provide real results. But using colored films just changes color, not wavelength.
For example, one common and beneficial wavelength to use for red light therapy is 660nm. PlatinumLED panels produce this wavelength directly from semiconductors using LED technology. A red halogen bulb would produce a variety of lights from a filament, and then pass them all through red glass.
When the light passes through the glass, any wavelengths that aren’t red are blocked, while the rest make it through. However, because red glass can’t control light at the wavelength level, all kinds of red light will get through. You’ll likely get some 675nm, 702nm, 800nm lightwaves, and more. It’s impossible to tell how much of each you’re getting.
Plus, this method of producing red light is extremely inefficient, because you’re blocking some of the light the filament produces. So you’d have to use an extremely powerful—and dangerously hot—light to produce enough power for therapy.
Beware Low-Cost Therapeutic Light Devices
Unfortunately, because halogen and fluorescent lights are cheaper to produce, many companies will use them to create red lights and market them as therapeutic devices. This is simply dishonest. Fortunately, it’s easy to spot a fluorescent or halogen bulb using the descriptions from earlier in this article. If the light looks like anything but an LED, look elsewhere for your light therapy needs.
Differences in LED Devices
Now, if you’d like to purchase an LED-based therapy panel, remember that all LED devices are not created equal. For instance, there could be differences in light output and irradiance, which will directly affect the amount of light that absorbs into your body.
When comparing red light therapy devices, look for the highest possible light energy output per irradiated area (irradiance), which is displayed as milliwatts per square centimeter, or mW/cm². Any reputable manufacturer will provide this information. The irradiance will vary based on the light energy output of the device and its distance from your skin.
Larger red light panels will deliver more light energy to the skin. The more LEDs there are on a device, the greater the irradiated area, and the better your results. So, a larger panel with more bulbs delivers more light to the treatment area. As the beams of light overlap somewhat, there will be greater absorption.
Even if you’re targeting a small area, like your wrist to help relieve carpal tunnel syndrome, keep in mind that the body is not a flat plane. There are bumps and dips, which means that light travels shorter distances to reach the bumps, and longer distances to reach the dips.
The longer the light has to travel, the less power it has to absorb into the skin. As long nothing interferes with light as it travels, it does not lose energy. However, light disperses as it travels away from the LED bulb. Plus, by the time the light reaches the skin, it's not as concentrated. That’s why a powerful light is necessary, and why it’s important to maintain a relatively close distance to the light for targeted applications.
The Best Lights, for the Best Results
You want results, and to get those results you need the best type of bulb as well as the most efficient and powerful red light therapy device.
Now that you understand the benefits of LEDs, check out the PlatinumLED BIO and BIOMAX series of compact and full-size red light panels. They offer increased irradiance and a patent-pending spectral configuration that combines the unique benefits of multi-wavelength red and near-infrared light.