What is near-infrared (NIR) light?
Near-infrared light is the band of light immediately beyond visible red light. In photobiomodulation (PBM), the practical therapy range is usually discussed as about 700-1100nm. Visible red light sits lower, roughly 620-700nm, and is easier to see with the eye. Far-infrared starts beyond the near-infrared band, often above about 1100nm, and is more associated with heat delivery than targeted PBM dosing.
That distinction matters because a user searching for near infrared light therapy is usually asking about invisible NIR wavelengths used by red light therapy panels, not an ordinary warming lamp. PBM mechanism reviews describe red and near-infrared light as non-ionizing wavelengths that interact with mitochondrial and non-mitochondrial photoacceptors [Passarella and Karu 2014, PMID:25226343]. Proposed PBM mechanisms include cytochrome c oxidase signaling, nitric oxide release, ATP changes, reactive oxygen species signaling, and downstream inflammatory modulation [de Freitas and Hamblin 2016, PMID:28070154].
Why NIR penetrates deeper than red light
NIR penetrates deeper because tissue does not absorb and scatter every wavelength equally. Melanin, hemoglobin, water, fat, and other tissue components all absorb light differently. Around the red and near-infrared range, there is a tissue optical window where less light is absorbed at the surface, so more photons can travel into soft tissue before being attenuated.
Many PBM discussions describe the most useful tissue-transmission window as roughly 650-950nm, with broader device-design discussions extending toward 1100nm depending on tissue type and target. This does not mean the same dose reaches every depth. It means wavelengths in this region generally have better biological access than blue, green, ultraviolet, or far-infrared light. Hamblin's 2017 review describes PBM as red and near-infrared light used to stimulate healing, relieve pain, and reduce inflammation, with cytochrome c oxidase and ion channels discussed as important chromophores [Hamblin 2017, PMID:28748217].
For consumers, the practical takeaway is simple: red wavelengths are useful for skin and superficial tissue goals, while NIR wavelengths are selected when the target is deeper muscle, joint, tendon, or bone-adjacent tissue. Wavelength still works with irradiance, fluence, beam size, treatment distance, and session time; it is not a magic depth switch by itself.
NIR wavelengths used in photobiomodulation
- 810nm - A common NIR wavelength near cytochrome c oxidase absorption discussions, frequently used when mitochondrial signaling and deeper tissue access are the goal.
- 830nm - A long-used PBM wavelength studied in tissue repair, collagen-related signaling, and mitochondrial response contexts.
- 850nm - One of the most common NIR wavelengths in consumer and clinical PBM devices because it balances availability, tissue reach, and a strong research history.
- 1060nm - The deepest-leaning NIR wavelength in Hale's panel stack, useful when the intent is broader coverage for joints, larger muscles, and bone-adjacent areas.
The mechanism literature does not reduce PBM to a single peak. Karu-associated work emphasizes that visible and near-infrared radiation can be absorbed by both mitochondrial and non-mitochondrial photoacceptors, and that cytochrome c oxidase, nitric oxide, and broader cell signaling remain central to the PBM model [Passarella and Karu 2014, PMID:25226343; Karu 2005, PMID:15739174].
Therapeutic depth penetration table
Penetration depth numbers are best treated as planning estimates, not universal guarantees. Skin tone, body site, fat thickness, blood volume, contact distance, beam area, and delivered irradiance can change the effective dose at depth. Still, wavelength comparisons help explain why NIR is used for deeper targets.
| Wavelength | Band | Approximate effective depth | Typical use case |
|---|---|---|---|
| 660nm | Visible red | About 1-3 mm | Skin, superficial circulation, wound-support research, surface tissue. |
| 810nm | NIR | About 3-5 mm | Muscle, tendon, nerve, and transcranial research contexts. |
| 850nm | NIR | About 5 mm+ effective therapeutic depth | General deep-tissue PBM and common full-body panel use. |
| 1060nm | NIR | Deepest of this set, often planned around 7+ mm | Large muscles, joint-adjacent tissue, and bone-adjacent coverage. |
Skin-focused PBM reviews support the use of red and NIR light for stimulation, healing, and restoration contexts [Avci 2013, PMID:24049929]. A head-tissue penetration review also shows why visible and NIR transmission varies widely by species, skull, scalp, and measurement setup [Salehpour 2019, PMID:31553265].
How Hale uses NIR
Hale RLPRO panels use eight wavelengths: four red wavelengths at 630, 650, 660, and 670nm, plus four NIR wavelengths at 810, 830, 850, and 1060nm. The RLPRO 1200 and RLPRO 2000 are Health Canada Class II licensed under Medical Device Licence #111226, FDA Establishment Registered, and specified at least 197 mW/cm2 irradiance. Hale also lists at least 160 mW/cm2 irradiance for the RLPRO 1000.
The 8-wavelength design is important because many panels stop at two peaks, usually 660nm red and 850nm NIR. A two-wavelength panel can be useful, but it leaves gaps. Hale's four red plus four NIR approach gives broader coverage across surface, mid-depth, and deeper tissue targets, while the 1060nm channel extends beyond the common 850nm-only NIR stack.
How to read an NIR device spec
A credible NIR therapy device should list exact peak wavelengths, not just "infrared" or "deep therapy." It should also explain irradiance at a useful treatment distance, because a high surface reading does not automatically mean useful dose at the body. For PBM, the key comparison is wavelength plus irradiance plus treatment area plus recommended time.
For example, a small 850nm wand may emit a valid NIR wavelength, but it treats a narrow area. A large multi-wavelength panel can deliver red and NIR light across the back, legs, shoulders, or torso with more even coverage. That is why Hale frames NIR as part of a full-dose system rather than a single LED color. The wavelength tells you where the photons sit on the spectrum; the panel design determines how repeatably those photons reach the tissue target.
NIR vs other terms
Near-infrared light is what this page covers: biological and therapeutic use of 700-1100nm light in PBM and red light therapy devices.
Near-infrared spectroscopy (NIRS) is different. NIRS is a measurement technique used in brain, muscle, and oxygenation research. It uses near-infrared light to measure tissue signals; it is not the same thing as using NIR light as a therapeutic intervention.
NIR Inc is unrelated to Hale and unrelated to near-infrared light therapy. Searches like "NIR today" can point to financial or company-name intent. Hale does not optimize this page for that query because it would confuse the topical signal of the page.
Common NIR therapy applications
- Muscle recovery: PBM in human muscle tissue has been reviewed for exercise performance, fatigue, and recovery contexts [Ferraresi 2016, PMID:27874264].
- Joint pain: NIR is commonly selected when the target is deeper than skin, such as knees, hips, shoulders, and tendon-adjacent tissue. Claims should still be condition-specific and dose-aware.
- Brain photobiomodulation: Transcranial NIR is an active research area with special constraints because scalp, skull, hair, and tissue geometry strongly affect delivered dose [Salehpour 2019, PMID:31553265].
- Wound healing: Red and NIR PBM has been studied in skin repair, healing, and restoration contexts [Avci 2013, PMID:24049929].
- Hair regrowth: A multicenter randomized, sham-controlled trial reported improved terminal hair density with a low-level laser device and no serious adverse events [Jimenez 2014, PMID:24474647].
Frequently Asked Questions
What is near-infrared light therapy?
Near-infrared light therapy uses non-ionizing 700-1100nm wavelengths to support photobiomodulation in deeper tissue than visible red light can typically reach. In consumer terms, it is the invisible NIR portion of red light therapy panels.
What wavelength is near-infrared?
Near-infrared begins just beyond visible red light. For PBM and Hale education, the practical therapy range is 700-1100nm. Hale's NIR wavelengths are 810, 830, 850, and 1060nm.
Is near-infrared the same as red light therapy?
No. Red light therapy is the broader consumer category. It often combines visible red wavelengths such as 630-670nm with NIR wavelengths such as 810-1060nm. Red is more surface-oriented; NIR is chosen for deeper tissue reach.
How deep does near-infrared light penetrate?
There is no single depth. As a practical planning range, 810nm may reach roughly 3-5 mm effectively, 850nm can be planned around 5 mm or more, and 1060nm is used for the deepest targets in Hale's wavelength stack. Tissue and dose setup change the result.
Is near-infrared light safe?
NIR PBM uses non-ionizing light, not ultraviolet radiation. Safety still depends on using a reputable device, following treatment times, avoiding direct eye exposure unless a protocol specifically allows it, and asking a clinician about implants, photosensitizing medicines, pregnancy, cancer history, or active medical conditions.
What does NIR stand for?
NIR stands for near-infrared. On this page it means near-infrared light therapy, not NIRS measurement technology and not the unrelated financial/company search intent around NIR Inc.
Which NIR wavelength is best for deep tissue?
For Hale panels, 1060nm is the deepest-leaning NIR option, while 810, 830, and 850nm cover widely used PBM research ranges. The best choice is usually a multi-wavelength panel rather than a single wavelength.
How is NIR different from infrared sauna?
NIR PBM uses specific wavelengths and dose control for photochemical signaling. Infrared sauna is primarily a heat exposure tool. Both involve infrared language, but they are different modalities with different dose logic.
Related Terms
Read next: photobiomodulation, peak wavelength, optical window, tissue penetration depth, and wavelength.
See also
For Hale's mechanism overview, see the science page. For commercial panel comparison, see Hale panels. For a deeper mechanism article, see how red light therapy works.