Red light therapy, near-infrared therapy, infrared therapy… it can get confusing!
One reason for this is that red light therapy commonly gets used as a catch-all term for light therapy in general. However, there are distinct differences between red light and near-infrared light therapy. Understanding these differences is crucial for both patients and clinicians to achieve optimal results.
Why the difference matters: Red and near-infrared light therapy use different wavelengths of light. These specific wavelengths significantly impact how deeply light penetrates the body. Ultimately, the depth of penetration needs to be sufficient to reach the intended target tissue.
For instance, red light, which uses shorter wavelengths, targets the skin more effectively. Near-infrared light therapy (longer wavelengths) penetrates deeper to target muscle and tissues.
So, which is better: Red light or near-infrared light therapy?
The answer depends entirely on the specific condition being treated. This guide provides a closer look at near-infrared vs red light therapy, key differences, and which conditions require RLT or NIR treatments. Plus, we’ll compare them to other photobiomodulation types like infrared and green light therapies.
Understanding Light Therapy: Red Light and Near-Infrared Light
Photobiomodulation, or light therapy, includes both red light and near-infrared therapy. However, photobiomodulation is a broad field. It also includes infrared light therapy (above ~900nm), blue light and green light therapies, among others.
No matter the type of photobiomodulation, the guiding theory is that specific wavelengths of light are believed to interact with the cells in our body. This interaction triggers a cascade of beneficial effects on a cellular level. Yet, depending on the cells you are targeting, the type of light (which corresponds to penetration depth) is important for optimal light therapy dosage.
Here are two important differences between red light therapy and near-infrared therapy:
1. Wavelength
The key to understanding red vs. near-infrared light therapy lies in the concept of wavelength and its relation to how deeply light can penetrate tissues.
Light is a form of energy that travels in waves. The distance between these waves is called wavelength, and it’s measured in nanometers (nm).
- Visible Light – Human eyes can detect light waves within a specific range of wavelengths, known as the visible light spectrum. Red light therapy (which typically uses wavelengths between 620-750 nm ), falls within this visible light spectrum. Green light is another visible light, as is blue light.
- Near-Infrared Light – Near-infrared light therapy, on the other hand, uses wavelengths just beyond the visible spectrum, ranging from about 805 to 855 nm. Infrared (above 900 nm) is also beyond the visible spectrum.
Why Wavelength Matters
According to 2017 study: “Wavelength is thus probably the single most important consideration in phototherapy, because without absorption, there can be no reaction.”
The reason is that different wavelengths penetrate deeper, and therefore, you have to choose the right wavelength for the tissue you are targeting. For example, blue light therapy is commonly used for acne treatments due to its antibacterial properties. However, the short wavelengths of blue light therapy (shorter than red or NIR) are not ideally suited to deeper issues.
In 2006, Michael Hamblin wrote that wavelengths between 600-700nm (for superficial tissues) and 780-950 (for deeper tissues) are a widely agreed upon parameter among researchers.
2. Penetration Depth
Generally, longer wavelengths of light (like infrared) penetrate deeper into tissues than shorter wavelengths.
This is because shorter wavelengths are more readily absorbed by the skin and other superficial tissues. Consequently, red light, with its shorter wavelength, primarily targets the skin and underlying layers. In contrast, near-infrared light, with its longer wavelength, can travel deeper to reach muscles, joints, and even bones.
Research suggests that near-infrared light around 750nm can penetrate deeper than 5mm into the skin, reaching muscle and tissues below the subcutaneous tissues. Additional studies have found even deeper penetration is possible with longer wavelengths of near-infrared light (800-855nm) and infrared light (900nm). For example, a 2023 study demonstrated that 1064nm infrared light penetrated the upper 10mm of skin more effectively than 905nm light.
Why Depth Matters
Red light typically penetrates the top 4-5mm of skin, making it ideal for stimulating cells in the epidermis and subcutaneous fat layer. This explains why red light is preferred for stimulating wound healing (as studied by NASA ) and promoting collagen production.
Near-infrared and infrared light therapies – which typically range from 800 to 900+ nm – typically are used to treat cells with higher mitochondria deeper in the body. For example, near-infrared light therapy more effectively targets the gut or kidneys.
Red Light vs Near-Infrared: Why the Difference Matters?
When light interacts with cells, it is absorbed by chromophores, which are light-sensitive molecules within the cell.
In the context of light therapy, the primary chromophore of interest is cytochrome c oxidase, located in the mitochondria, the cell’s powerhouse. For red light or near-infrared light to be effective, the light must reach the intended cells to be absorbed.
Once absorbed, this triggers three important benefits:
1. Increased Cellular Energy: When light is absorbed by cytochrome c oxidase, it triggers a chain reaction within the mitochondria, leading to increased production of Adenosine Triphosphate (ATP). ATP is the primary energy source for processes like cellular healing, repair and tissue regeneration.
2. Stimulate Nitric Oxide: Beyond increased ATP production, light therapy can also stimulate the production of nitric oxide, a molecule that promotes vasodilation (blood vessel widening) and improves circulation. Improved circulation allows oxygen and nutrients to flow more freely to the intended target to promote healing.
3. Inflammation and Oxidative Stress: Finally, light therapy can reduce inflammation and oxidative stress, creating a more optimal cellular environment for healing and function.
Which One Is Right: Red Light Therapy vs Near-Infrared?
As mentioned, the best form of light therapy depends on the tissues you are targeting. Here’s a look at which type of therapy is right for a range of conditions:
Red Light Therapy: Target Conditions
Red light primarily targets the mitochondria in the upper layers of the skin. This is why RLT is widely used for cosmetic LED facemasks, as well as in medical aesthetics.
An increase of ATP in these layers of skin can trigger a range of benefits including:
- Collagen and elastin synthesis
- Wound healing
- Tissue repair (reducing fine lines and wrinkles)
- Improving skin texture and tone
Additionally, within these upper layers of skin red light can downregulate the production of pro-inflammatory molecules and promote the release of anti-inflammatory mediators. This helps create a more favorable environment for healing and reduces skin conditions like acne and rosacea.
Some conditions that may be best suited for red light vs near-infrared light include:
- Wrinkles and fine lines
- Cystic acne
- Rosacea
- Eczema (psoriasis may benefit from red and NIR)
- Scarring
- Skin rejuvenation and overall skin health
- Superficial pain relief (arthritis pain in easily accessible joints)
- Muscle aches and soreness
Near-Infrared Light Therapy: Target Conditions
NIR therapy penetrates deeper tissues, reaching muscle cells, blood vessels, and potentially even bone cells. This deeper penetration can trigger a range of benefits like:
- Improved blood flow and delivery of oxygen and nutrients to deeper tissues
- Reduced inflammation
- Increased ATP production
- May also promote the release of growth factors and help stimulate tissue repair.
Some conditions that you might choose near-infrared vs red light for include:
- Muscle strains and tears
- Chronic pain (muscle tension, back pain)
- Joint pain (arthritis in deeper joints like hips)
- Sports injuries (promoting muscle recovery and reducing inflammation)
- Edema and localized circulation issues
- May be beneficial for promoting healing in deeper layers of tissue, potentially in combination with red light therapy for superficial layers.
Beyond Red and NIR: Infrared Light Therapy
Near-infrared (NIR) and infrared (IR) are often used interchangeably. Again, the distinction comes down to penetration depth and wavelength.
NIR vs. IR Therapy: Key Differences
Infrared light therapy encompasses a broader range of wavelengths, starting at about 900 nm and extending well beyond. NIR therapy, on the other hand, ranges from 805 to 855nm.
In terms of penetration depth, most research focuses on IR wavelengths of 950 and 1064nm. Generally, these wavelengths of IR light tend to penetrate further. However, the research is limited beyond these wavelengths. Additionally, higher wavelengths of IR light can begin to create heat and heat the tissues significantly, which is why far-infrared is commonly used in IR saunas.
Therefore, beyond 1064nm, IR wavelengths are commonly used for heat therapy rather than light medicine.
What Device Should You Buy? NIR or RLT?
If you’re shopping for a professional LED light therapy machine, we recommend that clinics choose a device that offers a wide range of red and near infrared wavelengths. Additionally, wavelengths of green and IR can be an added bonus.
For example, our Whole-Body Photobiomodulation Chamber offers a full spectrum of red and near-infrared light:
- 530nm (green)
- 610-633nm, 650nm (visible red)
- 810nm, 850nm (near-infrared)
- 940nm (infrared)
Our devices also offer light pulsing modes (which may influence penetration depth ). This full range of spectrums allows clinicians the ability to treat a wide range of conditions and generate positive results for patients.
For a comparison, see our guide to the best red light therapy beds.
Red Light vs NIR: Cost Differences
Cost is the final differentiator between these two therapies. Devices equipped with both red and near-infrared light tend to be costlier, but they offer users a wider range of applications.
Typically, low-cost red light masks tend to offer a limited range of wavelengths (often just 1 or 2) and no near-infrared capabilities.
Wrap Up: Choosing the Right Light Therapy for You
Red light and near-infrared (NIR) therapy offer a non-invasive approach to address various health concerns. Understanding the key differences between these therapies allows you to choose the most suitable option for your needs.
Here’s a quick recap:
- Red Light Therapy: Targets the upper layers of skin, promoting healing, rejuvenation, and reducing wrinkles and inflammation. Ideal for skin conditions and superficial pain relief.
- Near-Infrared Therapy: Penetrates deeper, reaching muscles, joints, and potentially bones. Promotes circulation, reduces inflammation, and may enhance tissue repair. Beneficial for muscle recovery, chronic pain, and deeper tissue issues.
However, the best approach isn’t one or the other. It’s both. Combining red and near-infrared light therapy has been shown to offer a wide range of benefits, allowing you to target a greater range of tissues and support your overall health.
Hue Light USA offers a full range of advanced photobiomodulation devices, including light beds, panels, mats and pads.
