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The Red Light Therapy Wavelength Explained: What To Know

Last Reviewed on April 1, 2024

Discover the science behind the red light therapy wavelength and its many benefits. Learn how this treatment works and what wavelengths are most effective.

Looking for a natural way to treat skin issues, pain, and inflammation?

Enter red light therapy. 

Red light therapy is a popular form of light therapy that uses specific wavelengths of red and near infrared (NIR) light to treat various conditions, including skin issues, pain, and inflammation. The red light wavelength has been shown to penetrate deep into the skin, where it can stimulate cellular activity and promote healing. 

In this way, red light therapy is believed to offer a range of benefits for both physical and mental health.

In this article, we’ll take a deep dive into red light therapy, including looking at the best wavelengths for your needs and discussing whether photobiomodulation therapy would be a good option for you. 

Keep reading to learn more about the red light therapy wavelength!

Understanding The Red Light Therapy Wavelength

In this section, we’ll go over the science behind red light therapy, including a comparison to other types of light therapy and the differences between red light therapy and NIR light therapy. 

What Is The Electromagnetic Spectrum?

Before we get into the wavelengths used for popular light-based therapies, let’s explain the electromagnetic spectrum. The electromagnetic spectrum refers to the range of all types of electromagnetic radiation, which includes various forms of light, radio waves, X-rays, gamma rays, microwaves, and infrared radiation.

Electromagnetic radiation is a type of energy that travels through space as waves, and each kind of radiation has a unique frequency, wavelength, and energy level.

Diagram of the electromagnetic spectrum, with a specific callout to visible light

For this article, we’ll be referring specifically to the wavelengths within the visible light range.

How Does Red Light Therapy Compare To Other Light-Based Treatments?

The first thing you should know about light therapy, also known as phototherapy, is that there is more than one kind. Most people living in the north will be familiar with using bright white light therapy, for example, to help with seasonal depression.

This section will compare red light therapy with 1) UV light therapy, 2) white light therapy, and 3) blue light therapy, three of the more common types of light therapy. 

What Is UV Light Therapy?

UV light therapy is a medical treatment that uses ultraviolet (UV) light to alleviate symptoms of certain skin conditions, like psoriasis and eczema.

The therapy involves exposing the affected area of the skin or the entire body to UV light for a controlled amount of time. The UV light in this therapy can be either UVA, UVB, or a combination of both.

UV light, such as the light from the sun, can have plenty of benefits in the therapy world.

The type of UV light used also affects the treatment.

For example, UVA light penetrates deeper into the skin and is commonly used to treat conditions such as psoriasis, eczema, and vitiligo. UVB, on the other hand, primarily affects the outer layers of the skin [1]. 

Diagram comparing UVA and UVB light and their impact on skin

UV light therapy works by slowing down the growth of skin cells and reducing inflammation. It can also help stimulate the production of vitamin D, which is essential for bone health and immune system function.

What Is White Light Therapy?

White light therapy is most typically used to treat seasonal affective disorder (SAD), as it involves the use of very bright white lights to mimic natural sunlight.

SAD is a type of depression that usually occurs during the fall and winter months when there is less natural sunlight. The therapy involves exposing the affected individual to bright light miming natural sunlight, typically 30 minutes to one hour daily.

While UV light therapy can also treat SAD (and may even be more effective than non-UV light therapy), it’s typically recommended to avoid using SAD lamps that produce UV light because of its long-term risks [2].

What Is Blue Light Therapy?

Blue light therapy is a type of phototherapy that uses blue light to treat various medical conditions, including skin and sleep disorders. The therapy involves exposing the affected areas of the body, typically the skin or the eyes, to specific wavelengths of blue light for a controlled amount of time.

The blue light used in therapy typically has a wavelength of around 400-500nm. This wavelength has been shown to penetrate the skin to reach sebaceous glands, which can help to reduce acne and improve skin texture. It can also be used as a treatment for psoriasis and other skin conditions [3].

Woman undergoing a blue light therapy treatment session

Besides its use in dermatology, blue light therapy can help regulate the circadian rhythm and treat sleep disorders such as insomnia and jet lag. Exposure to blue light can help to suppress the production of melatonin, a hormone that regulates sleep-wake cycles.

More specifically, a 2022 study investigated the impact of blue light therapy on patients with delayed sleep-wake phase disorder (DSWPD). The researchers concluded that “blue light therapy has a positive effect on improving subjective sleep quality, reducing the number of nocturnal awakenings and the duration of nocturnal awakenings, improving daytime function, and shifting the sleep phase forward in patients with DSWPD”. They even noted benefits in those without DSWPD [4]. 

What Is Red Light Therapy?

Red light therapy, which uses both red light and near infrared light, is used to treat a variety of medical and cosmetic conditions.

Red light wavelengths are typically between 600 and 700 nm, which is still in the visible light range. NIR wavelengths are typically between 700 and 1000 nm, which is just at the edge of visible light.

Red light has been shown to have various therapeutic effects, including promoting healing and reducing inflammation, chronic pain, and swelling. It has been used to treat acne, psoriasis, and joint pain.

Additionally, red light is believed to stimulate the production of collagen. This protein is crucial for skin health and can improve the appearance of wrinkles, fine lines, and other signs of aging. 

Differences Between Red Light and Near Infrared Light

Now that we have looked at the common forms of light therapy, let’s look a little closer at red light specifically.

There are two standard wavelengths in red light therapy, which fall under red light and near infrared. We’ll describe how both wavelengths behave and how they can be used in light therapy. 

Red Light: 620-750 Nanometers

In any light therapy treatment, the wavelength is important because it determines how deeply the light can penetrate the skin and tissues.

Diagram showing how deep each light wavelength penetrates into the skin

Red light is believed to penetrate the skin around 4-5 millimeters, depending on the specific wavelength [5].

While red light has wavelengths between around 620 to 750 nm, the optimal wavelength for red light therapy is in the mid-600 nm wavelength range.

As we noted above, red light therapy has a range of therapeutic applications, including reducing inflammation, pain, and swelling and promoting healing. 

Near Infrared Light: 750-1000 Nanometers

The near infrared wavelength has similar therapeutic properties as the red light wavelength, including reducing inflammation and pain and promoting the healing of wounds.

Where near infrared light differs is its ability to penetrate deeper into the skin and tissue because of its longer wavelengths.

Near infrared light therapy has been used to treat conditions such as arthritis, neuropathy, and musculoskeletal injuries.

While near infrared light has wavelengths between 750 to 1000 nm, the near infrared light used in red light therapy tends to be in the mid-800 nm wavelength range.

Characteristics of Each Wavelength

Red light and near infrared light are similar in what they can treat with some differences. Red light is known for treating surface-level issues, such as wrinkles and inflammation. 

If, on the other hand, you need deep healing, we recommend near infrared light instead. NIR wavelengths can penetrate deeper and promote healing down to the muscles and skeleton, as opposed to just a few millimeters into the skin. This deeper penetration makes near infrared light great for pain relief.

Red Light Therapy Wavelength Benefits

In this next section, we’ll look at the specific benefits of both red light wavelengths and near infrared wavelengths.

Reduced inflammation and pain: Red light therapy has helped reduce inflammation and pain in various conditions, such as arthritis, joint pain, and neuropathy. For instance, there was one study that investigated red light therapy’s impact on osteoarthritis. Elderly patients with degenerative osteoarthritis of the knee who received either red or near infrared light saw a 50% reduction in pain, while those in the placebo group did not report any significant improvements [6].

Man using red light therapy on his knee for pain relief

Improved skin health: Red light therapy is believed to stimulate collagen production, which can help improve the appearance of fine lines, wrinkles, and other signs of aging – making it a great choice for skin rejuvenation. In fact, in one 2014 study, researchers found red light therapy to have significantly improved “skin complexion, skin feeling, collagen intensity score, skin roughness, and wrinkle status” in a number of patients between the ages of 27 and 79 [7]. It can also improve skin texture and reduce the appearance of acne, scars, and other skin conditions.

Woman seeing fewer fine lines and wrinkles after using red light therapy

Improved muscle recovery: Red light therapy can help to improve muscle recovery after exercise or injury by increasing circulation and reducing inflammation. In particular, a 2006 study found red light therapy to significantly reduce the pain and discomfort associated with delayed onset muscle soreness (DOMS) [8].

Man using red light therapy while doing hammer curls at the gym

Enhanced wound healing: Red light therapy can help to promote the healing of wounds and injuries, including burns, cuts, and surgical incisions. More specifically, red light therapy works by reducing swelling, encouraging the growth of new blood vessels, increasing the production of collagen (which is essential for healthy skin), and promoting the creation of granulation tissue (which helps to heal wounds) [9]. 

Increased circulation: Red light therapy can help to increase circulation by stimulating the production of nitric oxide, which can help to dilate blood vessels and improve blood flow.

Improved cognitive function: Red light therapy has improved cognitive function in some studies, particularly in individuals with traumatic brain injury or cognitive impairment. A 2014 pilot, open-protocol study found red light therapy to result in improved social, interpersonal, and occupational function in 11 patients with chronic, mild traumatic brain injury [10].

Reduced symptoms of depression: Some studies have suggested that red light therapy may be effective in reducing symptoms of depression, although more research is needed in this area [11].

Choosing the Right Red Light Therapy Wavelength

Choosing the right wavelength for red light therapy depends on the treatment condition and the desired therapeutic effect. Red light wavelengths are defined as being between 620-750 nanometers, while near infrared light wavelengths are defined as being between 750-1000 nanometers.

Woman using a red light therapy panel with both red light wavelengths and near infrared light wavelengths enabled

Red light is typically used for superficial skin treatments, such as reducing the appearance of fine lines and wrinkles, improving skin texture, and reducing the appearance of acne and other skin conditions. 

On the other hand, near infrared light is often used for deeper tissue treatments, such as reducing inflammation and pain, improving muscle recovery, and promoting wound healing.

When choosing between red light and near infrared light, it is vital to consider the specific condition being treated and the desired therapeutic effect. 

For example, near infrared light may be more effective than red wavelengths of light if you want to reduce pain and inflammation in a specific body area.

However, red light may be more appropriate if you want to improve skin texture and reduce the appearance of fine lines and wrinkles.

Nowadays, most red light therapy devices allow you to customize which red light therapy wavelengths you want to use. You can turn on just red light wavelengths, just near infrared light wavelengths, or have both on simultaneously!

It is also important to consult with a healthcare professional before starting either red light therapy or near infrared light therapy to determine the most appropriate treatment plan and ensure the safe and effective use of the therapy. 

Additionally, taking proper precautions to protect your eyes from excessive exposure to light when using a red light therapy device is essential.

Final Thoughts

Many forms of light therapy have been shown to have several beneficial health effects, from promoting healing to improving the appearance of the skin to even helping mental health.

If you’re interested in red LED light therapy, we recommend speaking with your healthcare professional about which option is best for you given your specific use cases.


  1. https://my.clevelandclinic.org/health/treatments/24385-phototherapy-light-therapy
  2. https://pubmed.ncbi.nlm.nih.gov/2033028/
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8307003/
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8784911/
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5653719/
  6. https://pubmed.ncbi.nlm.nih.gov/1727843/
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/pmc3926176/
  8. https://pubmed.ncbi.nlm.nih.gov/16875447/
  9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4148276/
  10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4043367/
  11. https://pubmed.ncbi.nlm.nih.gov/26989758/
Anne, Founder of Therapeutic Beams

Anne Linde

Since using it to clear up her acne in college, Anne has been an avid user and fan of all things light therapy. She now primarily uses red light therapy for its anti-aging benefits. Anne's mission is to make the science behind red light therapy easy to understand and accessible, so anyone can use it to take control of their health and wellbeing.

John Ni, BSc.

John, a graduate of the prestigious University of Pennsylvania, serves as a respected scientific reviewer at TherapeuticBeams.com. His expertise extends across various domains, including chemistry, pharmaceuticals, and dermatology. He contributes to publications like Royal Society of Chemistry, Drug Topics, and Practical Dermatology.

John Ni, Content Editor & Scientific Review

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