Most people shopping for wellness technologies eventually encounter three terms:
- Red Light Therapy
- Near Infrared Therapy (NIR)
- Far Infrared Therapy (FIR)
They sound similar.
They are not.
Each wavelength occupies a different portion of the electromagnetic spectrum, penetrates the body differently, and has been studied for different health applications.
Understanding these differences helps explain why many modern wellness systems combine multiple wavelengths into a single experience.
Understanding Wavelengths
Light is energy.
Different types of light are measured by their wavelength, which is simply the distance between one wave and the next.
Shorter wavelengths are measured in nanometers (nm).
Longer wavelengths are measured in microns (µm).
One micron equals 1,000 nanometers.
This is why red light and near infrared therapy are usually discussed in nanometers, while far infrared therapy is discussed in microns.
Common Wavelength Ranges
Red Light Therapy
- Approximately 620–700 nm
Near Infrared Therapy (NIR)
- Approximately 700–1,400 nm
Far Infrared Therapy (FIR)
- Approximately 3–1,000 microns
Although all three forms of light exist on the same electromagnetic spectrum, they interact with the body differently because they occupy different regions of that spectrum.
What Is Photobiomodulation?
Photobiomodulation is the scientific term for using specific wavelengths of light to influence cellular activity.
In simple terms, certain wavelengths of light appear to help cells function more efficiently.
Researchers believe red and near infrared light interact with cytochrome c oxidase, an enzyme found within mitochondria that plays an important role in cellular energy production.
Cytochrome c oxidase sounds complicated, but it is simply one of the enzymes that helps cells convert oxygen and nutrients into usable energy.
Photobiomodulation is one of the most actively studied areas of light-based wellness research.
For a deeper discussion, see:
https://celebrationsaunas.com/photobiomodulation/
What Are Mitochondria?
Every cell in the body contains tiny structures called mitochondria.
Mitochondria are often described as the power plants of the cell because they produce the energy needed for cells to function.
Without energy, cells cannot repair tissue, build proteins, regulate inflammation, or maintain normal biological processes.
What Is ATP?
ATP stands for adenosine triphosphate.
Most people will never need to remember the name.
A simpler way to think about it is this:
If mitochondria are the power plants, ATP is the electricity they produce.
Every biological process in the body depends on ATP.
Building collagen.
Repairing tissue.
Moving muscles.
Supporting immune function.
Maintaining healthy skin.
Everything requires cellular energy.
For a deeper discussion, see:
https://celebrationsaunas.com/atp-and-mitochondria/
Red Light Therapy
Red light therapy uses visible red wavelengths.
The red light systems used in many modern saunas operate within the therapeutic red light range and peak at approximately 662.7 nanometers.
Red light is absorbed primarily by the skin and superficial tissues.
Because of this, most red light research focuses on:
- Collagen production
- Elastin production
- Skin rejuvenation
- Wound healing
- Tissue repair
- Circulation
- Cellular repair processes
Many dermatologists, estheticians, and wellness practitioners use red light therapy as part of skin health and anti-aging programs.
Researchers believe red light influences cellular signaling pathways that support normal repair and regeneration processes within the skin.
For a deeper review of the research, see:
https://celebrationsaunas.com/red-light-therapy-research/
Near Infrared Therapy (NIR)
Near infrared light exists just beyond the visible spectrum.
Although it cannot be seen by the human eye, it penetrates deeper into tissue than visible red light.
Near infrared therapy has been studied for:
- Recovery
- Muscle tissue
- Joint support
- Wound healing
- Exercise recovery
- Pain management
- Cellular signaling
- Photobiomodulation
Because near infrared penetrates deeper than red light, researchers believe it may influence biological processes in tissues that visible red light cannot reach as effectively.
Near infrared is often combined with red light because the two wavelengths complement one another.
Red light primarily affects superficial tissues.
Near infrared reaches deeper tissues.
Together they provide a broader range of light exposure than either wavelength alone.
For a deeper review of the research, see:
https://celebrationsaunas.com/near-infrared-therapy-research/
Far Infrared Therapy (FIR)
Far infrared therapy occupies a completely different region of the electromagnetic spectrum.
Unlike red light and near infrared therapy, which are primarily studied for photobiomodulation, far infrared therapy is most often studied as a form of heat therapy.
Far infrared wavelengths are measured in microns rather than nanometers because the wavelengths are thousands of times longer.
Celebration Saunas utilize far infrared heaters that emit wavelengths between approximately 8 and 10 microns, with approximately 87% of the energy concentrated around 9.4 microns.
Why is 9.4 microns important?
Because the human body naturally emits body heat at approximately the same wavelength.
This is one reason far infrared heat feels different than traditional convection heat.
Instead of simply heating the air around the body, far infrared energy is absorbed by tissues, creating a gentle warming effect from within.
Researchers have studied far infrared therapy for:
- Circulation
- Cardiovascular health
- Recovery
- Pain management
- Relaxation
- Flexibility
- Quality of life
Researchers have also proposed several mechanisms that may contribute to these effects, including improved circulation, heat shock proteins, nitric oxide pathways, cellular signaling, and mitochondrial function.
For a deeper review of the research, see:
https://celebrationsaunas.com/far-infrared-therapy-research/
Why Modern Wellness Technologies Combine These Wavelengths
Each wavelength appears to support different biological processes.
Red Light Therapy
Most commonly associated with:
- Skin health
- Collagen production
- Elastin production
- Tissue repair
Near Infrared Therapy
Most commonly associated with:
- Recovery
- Deeper tissue penetration
- Joint support
- Exercise recovery
- Photobiomodulation
Far Infrared Therapy
Most commonly associated with:
- Heat therapy
- Circulation
- Relaxation
- Recovery
- Cardiovascular support
Rather than competing with one another, these technologies often complement one another.
This is why many modern wellness systems combine multiple wavelengths into a single experience.
Which Wavelength Is Best?
That depends on the goal.
Someone focused primarily on skin health may be most interested in red light therapy.
Someone focused on recovery may be most interested in near infrared therapy.
Someone seeking the broadest range of documented sauna benefits may focus on far infrared therapy.
The reality is that each wavelength serves a different purpose.
Understanding those differences allows consumers to make more informed decisions about the technologies they use and the results they hope to achieve.
Related Reading
Photobiomodulation: Understanding How Light Influences Cellular Function
https://celebrationsaunas.com/photobiomodulation/
ATP and Mitochondria: Understanding the Body’s Cellular Energy System
https://celebrationsaunas.com/atp-and-mitochondria/
Red Light Therapy Research: What the Studies Show
https://celebrationsaunas.com/red-light-therapy-research/
Near Infrared Therapy Research: What the Studies Show
https://celebrationsaunas.com/near-infrared-therapy-research/
Far Infrared Therapy Research: What the Studies Show
https://celebrationsaunas.com/far-infrared-therapy-research/
What Is Waon Therapy? Understanding the Science Behind Far Infrared Sauna Research
https://celebrationsaunas.com/what-is-waon-therapy/
Sources & Further Reading
Photobiomodulation or Low-Level Light Therapy (Hamblin MR)
https://pmc.ncbi.nlm.nih.gov/articles/PMC5844808/
Red and Near-Infrared Light Therapy for Wound Healing and Tissue Repair
https://pmc.ncbi.nlm.nih.gov/articles/PMC5523874/
The Multifaceted Benefits of Passive Heat Therapies
https://pmc.ncbi.nlm.nih.gov/articles/PMC10989710/
Mayo Clinic – Infrared Sauna FAQ
https://www.mayoclinic.org/healthy-lifestyle/consumer-health/expert-answers/infrared-sauna/faq-20057954