Red Light vs. Infrared: What Are They?
Light-based therapies are becoming increasingly popular in wellness, recovery, and skincare, but terms like red light therapy and infrared are often used interchangeably. While they’re related, they are not the same. Understanding how they differ starts with one key concept: wavelength.
Understanding the Spectrum: Red Light vs. Infrared
What is Red Light?
Red light is part of the visible light spectrum, meaning it’s the portion of light your eyes can actually see. It typically falls within the range of ~620–750 nanometers (nm)¹². In therapeutic applications, most red light devices operate around 630–680 nm, delivering targeted light energy to the skin and tissues³. Because it’s visible, red light appears as a bright red glow during sessions—and unlike heat-based therapies, it produces little to no heat.
What is Infrared Light?
Infrared light sits just beyond the visible spectrum. It is invisible to the human eye and spans a much broader range—from about 780 nm to 1 millimeter¹. Infrared is further divided into three categories:
- Near-Infrared (NIR): ~750–3,000 nm
- Mid-Infrared (MIR): ~3–8 µm
- Far-Infrared (FIR): ~8–1,000 µm¹
There is some debate within the field on where mid and far infrared really differentiate, the numbers above are commonly followed within the industry. Each type interacts with the body differently, but the most important distinction is how it is experienced.
Visibility and What You Actually Feel
One of the biggest differences between red light and infrared therapy is how they feel during a session.
Red Light & Near-Infrared
- Red light is visible, while near-infrared is invisible
- Both are used in low-heat, light-based therapy
- Sessions feel mildly warm or neutral, without strong heat³⁴
These therapies are designed to trigger cellular responses, not heat the body.
Far-Infrared (Infrared Sauna Experience)
Far-infrared is completely invisible, but it is strongly felt as radiant heat.
- Produces a deep warming sensation
- Raises skin and muscle temperature
- Often leads to sweating, similar to a sauna⁵
This is why infrared sauna sessions feel fundamentally different; they provide a heat-based experiences, even though it is technically light.
Key Benefits to Consider
Red Light & Near-Infrared (Photobiomodulation)
Red and near-infrared light are used in photobiomodulation (PBM). Research suggests they can:
- Support cellular energy (ATP production)⁶
- Help with tissue repair and inflammation³⁶
- Improve skin health and recovery processes³
Near-infrared penetrates deeper into tissues compared to red light⁴.
Far-Infrared (Heat-Based Therapy)
Far-infrared works through thermal effects in addition to cellular signalling. It is associated with:
- Improved circulation and vascular response⁷
- Sweating and heat exposure benefits
- Relaxation and whole-body warming⁵
Penetration and Depth
- Red light: Surface-level (skin-focused)
- Near-infrared: Deeper penetration into muscles and tissues⁴
- Far-infrared: Deepest penetration which heats tissues
This makes near-infrared especially useful where deeper biological interaction is needed.
What a Session Looks Like?
Red Light / Near-Infrared Sessions
- Delivered via LED panels or wearable devices
- Visible red light + invisible NIR
- Low heat, little to no sweating
- Focused on cellular function³
Infrared Sauna (Far-Infrared Sessions)
- Delivered through infrared sauna systems
- No visible light, but strong heat sensation
- Noticeable sweating and warmth
- Raises skin and muscle temperature⁵ and increases heartrate
The Key Difference
-
Red Light Therapy
- Wavelengths: ~630–700 nm
- Little to no heat
- Focus: cellular activity (photobiomodulation)
-
Near-Infrared Therapy
- Wavelengths: ~700–2500 nm
- Little heat
- Focus: cellular activity and minor thermal effects
-
Far-Infrared Therapy (Infrared Sauna)
- Wavelengths: ~8–1,000 µm
- High heat
- Focus: thermal effects and circulation
Final Thoughts
Red light and infrared therapies similar, and do have many benefits that cross over, but they function very differently. One works through light-driven cellular processes, while the other produces a heated physiological responses. Understanding this distinction sets the foundation for choosing the right therapy, something we’ll explore in the next article.
No Commitment, No Spam.
Discover the psychological and biological tools that actually make a difference.
Get a free expert-developed e-book covering the top biological drivers of longevity and the psychology behind lasting wellness. Includes simple mental exercises and follow-up blogs to help you turn insights into real, lasting change.
Your information is secure with us. We’ll only send helpful, expert-backed content.
REFERENCES:
- 1. Hamblin M. et al. Mechanisms of Photobiomodulation. J Photochem Photobiol B. https://doi.org/10.1016/j.jphotobiol.2017.04.014
- 2. Salehpour F. et al. Applications of Photobiomodulation Therapy. Int J Mol Sci. https://doi.org/10.3390/ijms26115134
- 3. Yadav A. et al. Red and Near-Infrared Light Therapy Applications. Photodermatol Photoimmunol Photomed. https://doi.org/10.1111/phpp.12282
- 4. Rojas J. et al. Light Penetration in Biological Tissue. PLoS One. https://doi.org/10.1371/journal.pone.0047460
- 5. Crandall C. et al. Infrared Sauna Physiological Effects. Physiology. https://doi.org/10.1152/physiol.2025.40.s1.0304
- 6. Zomorrodi R. et al. Near-Infrared Effects on Brain and Mood. Biology. https://doi.org/10.3390/biology12010060
- 7. Winker R. et al. Infrared Therapy and Vascular Function. Thromb Haemost. https://doi.org/10.1055/a-2717-5157
- 8. Kocherova I. et al. Photobiomodulation Cellular Effects. Materials (Basel). https://doi.org/10.3390/ma14123427
