Red Light Wavelengths

Red Light Wavelength: Everything You Need to Know

various red light panels

If you’re buying a red light therapy panel, two of the most important questions you can ask are: 

Which red light therapy wavelength is best for my needs? 

And does this device I’m interested in offer those wavelengths? 

Today, many manufacturers only offer two wavelengths: the 660-nanometer (nm) red wavelength and the 850 nm near-infrared (NIR) wavelength. But if you just limit yourself to those two, standard options, you may be losing out on powerful benefits that other wavelengths provide. 

In this article, we explore the benefits of these two popular wavelengths along with other red and near-infrared (NIR) varieties. We’ll also discuss why using multiple wavelengths together could be the most effective way to get maximum results from this safe and natural therapy.

Why Are the Red and Near-Infrared Wavelengths Considered the Most Beneficial?

There’s no question that light therapy in general creates positive biological effects; in fact, the body needs light to be healthy. Natural sunlight has been used for centuries as a healing modality, although today we know that certain wavelengths can be beneficial as well as harmful.

For example, ultraviolet (UV) light therapy is used to effectively treat chronic skin conditions. Yet UV exposure should only be done in moderation since it is known to cause cell damage and even skin cancer.

Since blue light kills bacteria in skin tissue, blue light therapy is a popular acne treatment. Its use, however, could potentially cause problems. Most people are already over-exposed to blue light due to the regular use of computers, smartphones, and other electronics, and adding more for therapeutic reasons could backfire.

Blue light is now known to contribute to macular degeneration, and it may also accelerate skin aging. Because of those potential risks, we don't recommend the use of blue light devices as part of a daily skincare regimen.

Fortunately, based on years of study, researchers have identified a “therapeutic window” of certain wavelengths — red and near-infrared light — that appear to have significant biological benefits without any known side effects. 

Red light wavelengths chart

Conditions that can be successfully treated using red light therapy, as well as the optimal conditions needed to absorb the benefits of light therapy, are being studied with great interest as these natural remedies find more and more use in everyday healthcare.

Understanding Red Light Therapy Wavelengths

Red light therapy is more than just “red” light. It uses wavelengths in the visible (red) as well as the invisible (near-infrared) spectrum. And it also goes by a variety of names: You may have heard it called low-level light therapy (LLLT), photobiomodulation, or even low-level laser therapy, which are terms often used in scientific studies on red light therapy. 

Here are two quick technical notes to help avoid confusion:

  • Low-level laser therapy is a form of red light therapy, as it delivers the same wavelengths. But it uses low-level or “cold” lasers to deliver light to the skin; this differentiates it from red and NIR light therapy devices that use light-emitting diode (LED) bulbs, rather than lasers. Typically, low-level laser therapy is only used in clinical settings, whereas a wide variety of red/NIR light devices are available for home use.

  •  NIR light is technically within the infrared spectrum, although with a range of 780 to 1200 nm, it’s on the shorter end of the spectrum. This is where the body still perceives energy as light, rather than heat.

Although researchers often use lasers in their studies, LED light therapy devices are now being used more frequently. This is thanks to advances in LED technology and the fact that these devices are suitable for consumer use, meaning the results can be replicated at home.

What’s the difference between red and NIR wavelengths in terms of effect? 

The most common and profound effects of both red and NIR light include increased cellular energy, reduced inflammation, increased collagen production, and increased blood flow.

The difference lies in the ability of longer-wavelength NIR light to penetrate deeper into the body's tissues than red light.

Only Some Light Wavelengths Can Fully Pass Through the Skin

Any light that enters the body has to pass through the layers of the skin. Short wavelengths (such as blue light) barely scratch the surface, while long near-infrared wavelengths pass through all the skin layers deeper into the body.

The outermost layers of skin are actually made up of three different layers of tissue (seven layers if you include the four to five layers just within the epidermis).

The Epidermis

The epidermis, or the outermost part of the skin, provides a waterproof protective barrier for the body. This layer of skin is composed of four or five layers of epithelial cells. 

The epidermis is about .05 mm thick in the “thin skin” portions of the skin, and up to 1.5 mm thick in the “thick skin” portions of the body (the feet and hands, and particularly the heels).

The Dermis

Lying beneath the epidermis is the dermis, which is about 1 to 4 mm thick, depending on the location.

The Hypodermis

The deeper subcutaneous tissue, known as the hypodermis, is approximately 1 mm to 3 cm thick, depending on location. 

Tissues Beneath the Skin

Beneath the skin is muscles, bones, cartilage, various organs, blood, lymph, and interstitial fluid, which is the fluid that fills the spaces between cells.

Some bones, cartilage, tendons, muscles, and joints lie immediately beneath the surface of the skin (the knuckles, for example), so they are relatively easily within reach of red wavelengths. 

Some joints, like the knees, are quite large, however, as are the major leg muscles. Consider the thickness of these tissues, along with the thickness of the skin, to get an idea of just how far the light therapy wavelengths need to reach to be effective.

What Does This Mean for Red Light Therapy?

For any wavelengths to treat conditions deeper in the skin or beyond the skin, they must be long enough to get through the layers of skin: a combined total of anywhere from 2 mm (about the thickness of the eyelids) up to 3.5 cm (the thicker skin on the buttocks).

How Deep Does Red Light Therapy Penetrate?

The longer the wavelength, the deeper the absorption into the body. 

For “skin-deep” conditions, research has shown red light wavelengths to be most useful. For deep tissue applications, opt for near-infrared light, which can pass through all skin layers and even tough connective tissue and bone.

This illustration can help you visualize how deeply red and NIR light absorb into the body:

illustration of skin anatomy

[Illustration from a study published in the September 12, 2017 issue of Lasers in Medical Science.]

A 2017 study by researchers from the UK found that visible red wavelengths — including 610, 630, 650, and 670 nm red light — can absorb into the skin to a maximum depth of between 4 and 5 mm.

Another finding was that NIR light (810, 830, and 850 nm) can absorb into the tissue to a maximum depth somewhat greater than 5 mm, or a little over 2 inches. 

This absorption depth extends to the bone, muscle, blood vessels, organs, abdominal fat, lymph nodes, and other tissue and fluids well beneath the skin.

Studies have shown that NIR wavelengths ranging from 700 to 750 nm have limited biochemical activity and are therefore not often used. More research is needed; but in the meantime, light between 630–660 nm and 810–850 nm appears to have the most profound benefits; that’s the “therapeutic window” mentioned previously.

Beyond 1,000 nm, the story changes. Infrared saunas often use wavelengths longer than 1,000 nm as part of infrared light therapy — although this is another area where caution is advised due to the possibility of thermal damage.

Above 1,000 nm, the body begins to perceive the wavelengths as heat, not light. This is important for anyone treating their eyes, or trying to boost testosterone levels, because certain parts of the body, particularly the eyes and the testicles, are incredibly sensitive to thermal damage.

NIR light in the low 800 nm range generates negligible amounts of heat. This could make the treatment suitable (and safe) for applications in which far-infrared light could cause cell damage.

Keep in mind that these absorption depths for red and NIR light therapy are only general guidelines and refer to optimal conditions. The absorption depth of light photons can be influenced by the length of the treatment, any skincare products on the skin (which can block light), light-blockers such as hair or clothing, and the power of the LED light therapy device.

The Benefits of Red Wavelengths 

The most beneficial red light wavelength for skin is commonly considered to be 660 nm, which is near the upper range of visible red light. This wavelength has deeper penetration than the shorter 630 nm wavelength, with similar effects.

Red wavelengths penetrate the skin and sebaceous glands to rejuvenate the skin’s tone and texture. The 630 and 660 nm wavelengths are the two most widely studied wavelengths of the red light spectrum. Here’s a small sampling of some of the powerful benefits:

  • Improvement in chronic skin disorders like psoriasis: One study showed that the use of the 630 nm red light wavelength in conjunction with hematoporphyrin derivative (HPD) helped to eliminate the symptoms associated with psoriasis within 17 days.
  • Hair regrowth: According to a 2013 study, red light therapy containing the 630 nm wavelength is a safe and effective method of stimulating hair growth in both men and women.

  • Treatment of acne: A 2017 review published in Dermatology Times states that red light therapy could be a viable treatment for acne. Many popular LED light treatments for acne combine blue and red light; but with recent findings into potential skin-damaging effects of blue light, red light alone could be warranted as a treatment for the acne-triggering inflammation that contributes to breakouts.

  • Reduced training fatigue: A 2011 study revealed that red light at 660 nm combined with 830 nm NIR light can delay the development of fatigue in the muscles, and enhance skeletal muscle performance. (Athletes, take note.) This is one of many studies that suggest using more than one wavelength together could have profound benefits.

  • Reduced inflammation: In a study investigating the effects of red light therapy on pleurisy in rats, the 660 nm wavelength was found to induce an anti-inflammatory effect

  • Improved bone healing: A 2015 study found that red light at 660 nm was even more effective than the 830 nm wavelength in increasing ATP production in vitro and an initial acceleration of callus formation in the bone fracture healing process.

  • Reduced neuropathic pain: A 2014 study investigating sciatic nerve pain in rats found that the red 660 nm wavelength significantly helped to reduce pain.

  • Accelerated wound healing: In 2013, researchers conducting this study found that the red 660 nm wavelength increased the formation of new blood vessels and enhanced collagen deposition to help in the healing of wounds.
     

On their own, the 630 nm and 660 nm red light wavelengths are highly beneficial. But you’ll get the best results by combining shorter and longer wavelengths in the visible and invisible light spectrum.

The Benefits of Near-Infrared Light Wavelengths

The “best” NIR wavelength for deep-tissue treatment is typically believed to be 850 nm, which is near the upper range of NIR light. Here’s a small sampling of the findings of various studies and clinical trials on the effects of the most widely studied wavelengths ranging from 810 to 850 nm.

An especially exciting discovery of several studies is near-infrared light’s promise in enhancing brain health — including treatment of brain disorders and recovery from brain injuries.

With its ability to penetrate through the skull and into brain tissue, the 810 nm wavelength offers a unique array of neurological benefits. Many forward-thinking scientists share the belief that NIR light therapy will become a prominent medical treatment for brain disorders in the near future. 

  • Improved recovery from stroke in certain patients: One study conducted with stroke patients showed that 810 nm NIR light wavelengths provided neuroprotective benefits and improved recovery among sufferers of moderate to severe strokes. Five days after the stroke, there was significant improvement among those who had been treated with 810 nm light therapy, compared to those who hadn’t. Ninety days post-stroke, 70 percent of the treated patients had a successful outcome, compared with only 51 percent of the control group.

  • Improved recovery from traumatic brain injury: As confirmed by this pilot study in 2007, 810 nm NIR light therapy has been shown in animal models to be particularly effective in promoting recovery from traumatic brain injuries and reducing long-term neurological damage.

  • Interest in the ability of near-infrared light to support improvement in psychiatric disorders goes as far back as this 2009 pilot study co-authored by world-renowned red light therapy expert Michael Hamblin. Prescription drugs have long been recognized as having a limited ability to assist individuals suffering from psychiatric conditions, and often come with a host of unwanted side effects. In this study, 810 nm NIR light applied to the forehead was shown to help patients suffering from major depression and anxiety, with no adverse side effects.
  • A 2018 review of several studies confirmed the neuroprotective effect of near-infrared light on the brain.

Other benefits of NIR wavelengths include:

  • Improved healing and recovery: A 2017 study of soccer players showed that the 810 nm wavelength applied before activity enhanced muscular performance and post-exercise recovery.

  • Accelerated wound healing: This 2014 study found that 810 nm wavelengths helped expedite wound healing in diabetic rats, which enabled the tissue to granulate more rapidly. A study from 2013 suggests that the 830 nm wavelength accelerates healing in wounds and helps to ward off infection. In this small study, which involved five patients with various types of wounds, all five of them experienced wound healing, controlled infection, and lessened discomfort during treatment periods ranging from one to eight weeks (depending on the severity of the wound).

  • Improved outcomes following plastic surgery: During a 2015 study, South Korean researchers found that swift exposure to 830 nm wavelengths after aesthetic surgery hastens recovery, reduces downtime, and enhances the results of surgery by reducing swelling, infection, bruising, and pain.
      
  • Improved bone repair and growth: A 2008 study by researchers from Brazil demonstrated that 830 nm light therapy improved bone repair by stimulating new bone growth. 

  • Faster return-to-play after injury: The ability to return to play as swiftly as possible after injury or trauma is a key concern for any amateur or professional athlete. This 2016 study confirmed that 830 nm NIR  light therapy significantly and safely reduced the wait time before injured athletes could return to play. Over a 15-month period, 395 injuries were treated with 830 nm light therapy, including sprains, strains, ligament damage, tendonitis, and contusions. The study authors found that the treatment successfully brought about accelerated healing in all wounds at different stages, and successfully controlled secondary infection.

  • Enhanced muscle recovery after a hard workout: A 2016 study co-authored by Hamblin observed the use of 850 nm wavelengths on athletes and found that the use of NIR light increased muscle mass after training and decreased inflammation and oxidative stress in muscle biopsies.

  • Orthodontics and tooth alignment: A clinical trial published in 2016 confirms that using the 850 nm wavelength supported faster realignment of teeth for patients undergoing orthodontics. 

As valuable as these results are, it bears repeating that better results could be expected by combining wavelengths in the red and NIR spectrum. Let’s explore that now.

What Is the Best Wavelength and Spectrum for Red Light Therapy?

Ultimately, this comes down to one question: Which wavelength will give you the results you want?

The short answer is that you’ll get the best results by using red (610–660 nm) and near-infrared (820–850 nm) wavelengths simultaneously. By combining multiple wavelengths of red and NIR light, you’ll experience superior results. 

close up of red light therapy panel

The Therapeutic Spectrum: Harnessing the Power of Five Wavelengths

Let’s start with the red wavelengths. If you use 630 nm light along with 660 nm light, the shorter 630 nm wavelengths will, of course, have a shallower absorption depth. 

As the light photons pass through these layers to reach their maximum absorption depths, they travel together, increasing the effect on the tissue that is within the range of both wavelengths.

As they move through the tissue, both wavelengths will work together up to about 4 mm. After that, the 630 nm wavelengths are extinguished while the 660 nm wavelengths continue into slightly greater absorption depth before extinguishing.

This two-wavelength combination will help reduce the loss of energy that occurs as light photons pass through the body — and when you add longer wavelengths to the mix, you exponentially increase the number of light photons interacting with your cells.

If you shine five wavelengths (630 nm, 660 nm, 810 nm, 830 nm, and 850 nm) on the target treatment area simultaneously, something incredible happens: the longer wavelengths amplify the effects of the shorter wavelengths.

As the light photons enter the skin, all five wavelengths interact with the tissues they pass through. It’s very “bright” in the irradiated area, and this five-wavelength combination has a significant impact on the cells in the treatment area.

Some of the light photons scatter and change direction, creating a “net” effect in the treatment area in which all wavelengths are active. This net effect receives the light energy of five different wavelengths.

The net will also be bigger when you use a larger light therapy device; but for now, we’ll stay focused on how the individual light photons behave in the body.

The below illustration, from the 2017 study by UK researchers previously referenced, shows how light penetrates deep into the body’s tissues. This may help you visualize how the scattering effect works:

illustration showing light penetration on body tissue

As the light energy of the 630 nm wavelength is extinguished, the remaining four wavelengths continue passing through the tissues. 

The impact of the 660 nm wavelength penetration depth is amplified by the longer wavelengths traveling alongside and scattering together. It’s still four wavelengths working together to a depth of about 5 mm.

Once the 660 nm wavelength departs the group, the 810, 830, and 850 nm wavelengths continue passing through tissue together in straight and scattered formations.  

While the light energy does indeed dissipate as the light photons pass through the body, these distinct wavelengths work together to “saturate” the cells with more light energy.

Finally, there’s just the 850 nm wavelength left, traveling to its maximum absorption depth of slightly more than 5 mm. Even if a percentage of the light photons from this wavelength have dissipated, some will reach their target tissue deeper in the body. 

This spectral output results in an unprecedented synergy that ensures each layer of tissue — within the skin and below the skin — receives the maximum light energy possible.

The advantage of using multiple wavelengths has been confirmed in numerous studies, such as one chronicled in this 2012 paper in MedEsthetics. The study found that while both red and NIR wavelengths work in promoting collagen production, patients treated with a combination of either 630 nm/850 nm LED or 660 nm/830 nm LED showed superior results.

How to Harness the Power of Five

Since most red light therapy devices feature just two wavelengths, how can you benefit from five?

Only one device on the market features this five-wavelength spectral array: the BIOMAX series from PlatinumLED Therapy Lights.

The BIOMAX panels deliver these widely studied wavelengths together, which means you never have to wonder which one to choose. If you’re treating more than one condition, for example, such as fine lines and wrinkles along with a deep muscle bruise, you will get more profound and faster results by using all five wavelengths at once.

But the wavelengths are only part of the picture.

Light Power Output Helps Ensure Optimal Light Photon Absorption

Along with using the right wavelengths, you'll want to use a high-power-output LED light therapy device; otherwise, your red light therapy treatment sessions could be much longer and may not yield the best results.

Why? Because, as we illustrated earlier, light loses energy as it passes through tissue, absorbing and scattering depending on the material it encounters.

Scattering doesn’t cause light photons to lose energy; it just redirects them, which means they may travel “sideways” as opposed to straight into the tissue. 

However, absorption into certain kinds of tissue (most notably, the tissue where a lot of water is present) can interfere with light photons passing through, and result in shallower tissue penetration.

This means ample light photons are required to ensure that the maximum amount of light reaches the targeted tissue — and that requires a light therapy device with more power.

The power output of the red light device is very important to deliver the maximum amount of light intensity to the skin. Even between similarly sized panels, the difference in power output (not power consumption) can be astonishing.

Typically, a larger light therapy device will have more light power output. It’s important, however, to compare the output of any light therapy device you're considering to ensure you’re getting the most potent light intensity, and therefore, the most value.

Irradiance: The Number That Matters When Comparing Devices

The light energy output of an LED light therapy device is measured in milliwatts per square centimeter, or mW/cm². This is known as irradiance, and it’s the number you’ll want to compare to understand which red light device will give you the best results.

A red light therapy device that delivers 183 mW/cm² is substantially more powerful than a device that delivers 60 mW/cm² at the same distance — meaning, the more powerful device will allow more light photons to absorb to their maximum possible depth in the body.

An extremely powerful red light therapy device such as the PlatinumLED Therapy Lights BIOMAX 900 could “push” more light photons deep into the body’s tissues.

Here’s an example of how important irradiance is. If two red light devices deliver the same wavelengths, the penetration depth — or the maximum that a particular wavelength can travel — would theoretically be the same.  

However, more power output increases the number of light photons that can penetrate the targeted tissue to spark biological processes in the cells. An underpowered device won’t deliver the light photons with the intensity needed to push the light deep into your body. 

How Does Red Light/NIR Light Work?

man holding red light panel

Now that you know which wavelengths are best for certain applications, here’s an overview of what actually happens when the light photons interact with your body.

Correcting Mitochondrial Dysfunction

All the cells in the human body perform their specialized functions, and our health is dependent on healthy cells. Whenever anything interferes with normal cellular functioning, there’s a ripple effect on the system the cells are part of and even on the body as a whole.

For a cell to be healthy it needs enough energy. Producing that energy is the role of mitochondria, which are organelles inside cells that act like tiny power generators. The mitochondria produce adenosine triphosphate (ATP), the primary fuel that provides cells with the energy they need to function. 

According to numerous studies, the key to treating many physical conditions appears to be using red light therapy (both red and NIR light) to enhance cellular energy production in the mitochondria.

The mitochondria are susceptible to damage from oxidative stress caused by inflammation. This can lead to a condition known as mitochondrial dysfunction, meaning the inability of the mitochondria to convert raw materials into energy. Emotional stress, injury, and disease can also interfere with proper mitochondrial functioning.

Mitochondrial dysfunction is considered a major contributing factor or cause of poor physical functioning and even disease.

A 2020 scientific article in the publication Frontiers in Aging Neuroscience links mitochondrial dysfunction to Parkinson’s disease, which is a central nervous system disorder. The same article suggests that red light therapy could be a potential treatment for Parkinson’s.

Here's how it works.

During a red light therapy treatment, chromophores within the mitochondria absorb red and NIR light photons, and in turn, are stimulated to produce more ATP. Just as depleted cells have a negative ripple effect on neighboring cells, their system, and even the body as a whole, the opposite is also true — energized cells have a positive ripple effect.

One example of this ripple effect is that when cells like fibroblasts are stimulated to synthesize proteins like collagen and elastin, this process can improve skin health and also the repair and health of the muscles and joints. 

You could compare the process to photosynthesis, whereby plants absorb sunlight and convert it into energy. In red light therapy, our cells absorb the energy of the red and near-infrared light photons, which enhances our cellular potential by promoting oxygen utilization within the cell and generating ATP.

Reduced Inflammation

Red light therapy works by stimulating energy production in cells to halt and even reverse mitochondrial functioning — but that’s not all. It also reduces the inflammation that could be causing the problem in the first place.

When we are unwell, stressed, or injured, the ability of cellular mitochondria to function at full capacity becomes impaired. In the fast-paced, stress-saturated context of the modern world, most of us are uncomfortably aware of the effects of constant underlying tension.

The skin is the first place we tend to notice chronic stress-related inflammation.

When we are stressed or ill, mitochondria begin to produce excess nitric oxide. This is problematic because nitric oxide interferes with the consumption of oxygen within cells, which can lead to oxidative stress, and ultimately, cease the production of ATP. Affected cells may die as a result.

According to this 2017 article by Hamblin, red and NIR light has been shown to reduce inflammation, which can protect cells from the damage that nitric oxide can cause. This suggests that reducing oxidative stress in the cells can support optimal mitochondrial functioning.

Again, there’s that ripple effect throughout the neighboring cells, the system the cells belong to, and to a lesser degree, the body as a whole since all systems are interconnected.

How to Use Red Light Therapy at Home

platinum led panel next to the couch

To get the best results, we recommend using a spectrum of wavelengths together, delivered by a high-light-power energy red light device such as the BIOMAX 600. It is a versatile mid-sized red light device suitable for both targeted and larger applications.

What You'll Need

Extensive research and development by our engineering and medical advisory staff led to the development of BIOMAX lights, which feature the patent-pending R+ | NIR+ spectrum. This spectrum merges five different wavelengths of red and near-infrared light: 630 nm, 660 nm, 810 nm, 830 nm, and 850 nm in a synergistic combination to deliver unmatched therapeutic value.

You could get good results by using a two-way combination of the 660 nm and 850 nm wavelengths, but you may experience somewhat slower results.

The Right Wavelengths

If your red light therapy device gives you a choice of wavelengths, choose specific wavelengths that are most relevant to your treatment goals: red light for “skin-deep” conditions, and near-infrared light for deep tissue concerns.

Many devices will also allow you to use both wavelengths together. This can be beneficial for skincare: You can increase collagen production and microcirculation, and address any underlying inflammation with the longer NIR light wavelengths.

As mentioned earlier, all lights in the PlatinumLED Therapy Lights BIOMAX series do away with the need to choose: all five wavelengths are delivered simultaneously.

How Often to Use Your Red Light Therapy Device

There are no hard and fast rules, but starting slowly is generally recommended.

You could start with shorter red light therapy sessions of just a few minutes a day, gradually working up to 10- to 20-minute sessions three to five times a week. 

Be sure to consult your doctor before starting red light therapy, especially if you are treating any chronic conditions, your eyes, or other very sensitive parts of the body.

Patience and Consistency Are Important

Since red light therapy works at the cellular level, it’s important to be patient, be consistent with the treatment, and give your body a chance to heal.

This could take anywhere from one to four months for most conditions as individual cells heal and resume normal functioning, and new healthy cells are born.

You could also continue red light therapy on an ongoing basis to maintain your results.

This can be beneficial if you're an athlete striving to maintain peak physical conditioning; someone who wants to turn back the clock on just your face and regain a more youthful appearance; or someone who is suffering from a chronic skin disorder.

The Takeaway: All Red and NIR Wavelengths Are Beneficial — but They're Best in Combination

In this article, we discussed the unique benefits of red and near-infrared wavelengths: how using them together creates a synergy that can amplify the benefits of each wavelength and ensure more comprehensive treatment.
Learn more about the most powerful red light therapy devices on the market, the PlatinumLED BIOMAX series, here, and browse the Learn page to discover the many and often surprising ways that red light therapy can enhance your health and well-being.