Light Therapy Wavelength Chart

A practical reference to visible-light and near-infrared wavelength regions, common consumer-device examples, research contexts, and the limits of interpreting wavelength without output, distance, exposure time, device geometry, and measurement data.

Violet

Blue

Cyan

Green

Yellow / Amber

Red

Near-Infrared

Open Biohacking Data Project Reference

This wavelength chart is a human-readable educational resource within the Holistix Open Biohacking Data Project.

The primary related canonical datasets are:

Current project release: v1.5.0

Canonical v1.5.0 DOI: 10.5281/zenodo.21862535

Project concept DOI: 10.5281/zenodo.20978709

This chart is an interpretation and navigation layer. It does not replace the canonical machine-readable datasets, device specifications, manufacturer instructions, or product-specific evidence.

Core interpretation rule: A wavelength tells you where light sits on the electromagnetic spectrum. It does not independently tell you the irradiance, fluence, treatment area, penetration at a specific target, thermal behavior, safety profile, clinical indication, or expected outcome of a particular device.

Visible and Near-Infrared Wavelength Reference

Wavelength boundaries vary somewhat among scientific, engineering, lighting, and device contexts. The ranges below are therefore educational reference regions rather than universal regulatory definitions.

Region / Color	Reference Wavelengths	Optical Context	Common Research or Device Context	Interpretation Limit
Violet	Approx. 380–450 nm	Short visible wavelengths with relatively superficial optical interaction compared with red and near-infrared light.	Violet and violet-blue wavelengths appear in research and devices involving surface illumination, microbial photoinactivation, dermatology, photochemistry, and specialized optical applications.	A violet wavelength alone does not establish antimicrobial performance, acne treatment, wound healing, safety, or clinical effectiveness.
Blue	Approx. 400–495 nm	Visible short-wavelength light with comparatively superficial interaction in skin relative to red and near-infrared wavelengths.	Blue-light devices and research may involve acne-related applications, photodynamic or photochemical contexts, circadian-light research, dermatology, and other optical uses.	Results from a particular blue-light wavelength, dose, device, or clinical study should not automatically be generalized to every blue LED.
Cyan	Approx. 470–500 nm	Transitional visible region between blue and green.	Cyan wavelengths appear in optical, visual, lighting, photochemical, and emerging research contexts.	Consumer wellness claims for cyan light require wavelength-specific, device-specific, and outcome-specific evidence.
Green	Approx. 495–570 nm	Mid-visible-spectrum light with optical behavior distinct from both short blue wavelengths and longer red wavelengths.	Green-light research includes visual neuroscience, photophobia and migraine investigations, dermatology, illumination, and other experimental contexts.	Early or condition-specific research should not be converted into a claim that ordinary green LEDs universally treat migraine, pigmentation, inflammation, or neurological conditions.
Yellow / Amber	Approx. 570–600 nm	Visible wavelengths between green and orange-red regions.	Yellow and amber wavelengths appear in dermatology, cosmetic-device research, lighting, photobiology, and specialty illumination contexts.	Wavelength alone does not establish effects on redness, lymphatic function, pigmentation, inflammation, or post-procedure recovery.
Orange	Approx. 590–620 nm	Longer visible wavelengths approaching the red region.	Orange wavelengths appear in illumination, cosmetic-device, photobiology, and experimental optical contexts.	Orange light should not be assumed to produce pain relief, cognitive effects, blood-flow changes, sleep benefits, or other outcomes without evidence for the specific exposure.
Red	Approx. 620–700 nm Common device examples: 630, 633, 660 nm	Longer visible wavelengths used extensively in photobiomodulation and light-device research.	Red-light research includes dermatology, photobiomodulation, wound and tissue research, cosmetic applications, and other device-specific uses.	A red wavelength alone does not establish irradiance, fluence, treatment depth, collagen response, pain relief, wound healing, or clinical effectiveness.
Deep Red	Approx. 660–700 nm	Long visible-red wavelengths approaching the near-infrared boundary.	Frequently overlaps with photobiomodulation, tissue-optics, dermatology, and red-light device research.	“Deep red” is descriptive language, not proof that a consumer device reaches a defined anatomical depth or produces a particular biological effect.
Near-Infrared	Common PBM examples: 810, 830, 850 nm	Invisible near-infrared wavelengths commonly used in photobiomodulation and optical-tissue research.	NIR research includes photobiomodulation, tissue optics, rehabilitation research, musculoskeletal applications, neurological research, and other device-specific contexts.	General evidence involving one NIR wavelength, irradiance, fluence, device, or target tissue should not automatically be transferred to another NIR device.
Near-Infrared	Common consumer examples: 850, 880, 940 nm	Invisible NIR wavelengths whose tissue interaction differs according to wavelength and the complete exposure conditions.	Used across consumer LEDs, optical sensing, illumination, imaging, engineering, and selected wellness-device designs.	A larger wavelength number does not automatically mean greater power, deeper useful exposure, higher quality, more heat, or greater effectiveness.
Far-Infrared	Longer-wave infrared region	Commonly encountered in thermal and heat-focused applications rather than conventional red/NIR LED dose discussions.	Infrared saunas, sauna blankets, thermal emitters, heating systems, spectroscopy, sensing, and other infrared technologies.	Far-infrared terminology does not prove detoxification, disease treatment, superior circulation, weight loss, or another medical outcome. Heat exposure should be evaluated through temperature, duration, hydration, device design, and safety instructions.

Spectrum boundaries differ somewhat among references and industries. The wavelengths shown above are educational reference regions and examples, not universal definitions of every device class.

Why We Removed Exact “Penetration Depth” Numbers

It is tempting to build a chart saying one wavelength penetrates exactly 1 mm, another 10 mm, and another 40 mm.

That looks wonderfully precise. Unfortunately, biological tissue did not sign the spreadsheet.

Optical transport depends on more than wavelength. Relevant variables include:

wavelength
skin and tissue composition
pigmentation
water content
blood and other chromophores
absorption
scattering
device irradiance
beam geometry
distance
contact versus non-contact use
exposure duration

Red and near-infrared wavelengths are commonly investigated because their optical transport characteristics can differ from shorter visible wavelengths, but a wavelength should not be translated into one universal anatomical penetration depth for every device and every person.

Wavelength Is Not Irradiance

Wavelength is measured in nanometers.

Irradiance describes radiant power reaching an area under stated measurement conditions.

Two devices can both use 660 nm LEDs while producing substantially different irradiance.

For the dedicated explanation, see What Is Irradiance in Red Light Therapy? .

Wavelength Is Not Fluence

Fluence describes energy delivered per unit area over an exposure period under stated measurement assumptions.

A wavelength label does not tell you the fluence.

Useful exposure context includes irradiance, time, distance, treatment geometry, active wavelength channels, measurement method, and device operating mode.

See What Is Fluence in Red Light Therapy? and the Red Light Therapy Dose Chart .

Red Light vs Near-Infrared

Red light is visible. Near-infrared light is generally invisible to the human eye.

Both regions appear extensively in photobiomodulation research, but they should not be treated as interchangeable.

Device comparison should include:

wavelength
irradiance
fluence or exposure calculation context
distance
coverage area
beam angle or optical geometry
session duration
heat
eye-safety instructions
intended use

See 660 nm vs 850 nm Red Light Therapy .

850 nm vs 940 nm

Both 850 nm and 940 nm are near-infrared wavelengths.

Neither is automatically stronger, hotter, deeper-reaching, safer, or better merely because of the wavelength number.

See 850 nm vs 940 nm Near-Infrared Light .

Blue Light Needs Its Own Safety Context

Blue light is not simply a shorter version of red light.

Its optical behavior, biological interactions, device applications, and eye-safety considerations differ.

Research involving blue-light acne devices, photodynamic therapy, circadian exposure, or another blue-light application should not automatically be generalized to every consumer blue LED.

See:

Near-Infrared Is Not the Same as Far-Infrared Heat

Consumer wellness marketing often compresses all infrared technologies into one bucket.

That is not useful.

Near-infrared LED devices are commonly interpreted through optical variables such as wavelength, irradiance, distance, fluence, geometry, and time.

Infrared sauna blankets and other thermal devices are commonly interpreted through variables such as temperature, session duration, body contact, enclosure, hydration, and thermal tolerance.

See:

What a Transparent Light Device Should Disclose

A useful light-device listing should disclose as many of the following as practical:

nominal wavelength or wavelength range
all active wavelength channels
irradiance
measurement distance
measurement method or instrument where available
whether output is center-point or area-average
treatment or illumination area
device format
session instructions
operating modes
thermal behavior
eye-safety guidance
contraindications and warnings
whether specifications are measured, calculated, estimated, or manufacturer-reported

See the Holistix Wellness Device Transparency Standard .

Canonical Machine-Readable Light and Infrared Data

The canonical Holistix datasets remain version v1.2.

Project-Level Machine-Readable Context

Holistix Open Biohacking Data Project v1.5.0 adds interoperability and reproducibility infrastructure around the canonical subject datasets, including Data Package metadata, deterministic JSONL exports, Schema.org JSON-LD catalog metadata, RO-Crate 1.2, provenance records, release-lineage metadata, supersession metadata, and reproducible build tooling.

These project-level formats do not replace the canonical subject datasets and do not change their v1.2 dataset versions.

Related Holistix Light Reference System

Open Biohacking Data Resources

Sources and Research Context

Wavelength is an important light-therapy variable, but research interpretation also requires output, exposure, device, target-tissue, safety, and study-design context.

External research is included for scientific and measurement context. It does not establish that any specific Holistix consumer product reproduces the same exposure conditions or clinical outcomes.

Important Safety and Claim Boundary

This chart is provided for educational and informational purposes only.

It is not medical advice, diagnosis, treatment guidance, wavelength-prescription guidance, dosage guidance, eye-safety clearance, regulatory advice, or proof that a particular wavelength prevents, treats, cures, repairs, mitigates, or diagnoses disease.

Light-sensitive medical conditions, medications that increase photosensitivity, eye conditions, recent eye procedures, and device-specific contraindications may require additional professional guidance.

Follow the instructions and safety information for the specific device being used.

Explore Holistix Light Devices

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Open wellness technology data, educational references, and device transparency

Page History

August 10, 2026: Synchronized the Light Therapy Wavelength Chart with Holistix Open Biohacking Data Project v1.5.0; connected Red Light Dose Index v1.2, Blue Light Therapy Reference Index v1.2, and Infrared Therapy Reference Index v1.2; removed fixed universal tissue-penetration values; replaced broad treatment and benefit claims with research-context and interpretation-boundary language; removed unsupported detoxification claims; separated visible light, NIR optical exposure, and far-infrared thermal exposure; removed a non-sitemap chart-embed URL; added current authority-spine links and canonical machine-readable resources.

Last updated: August 10, 2026

Current Open Biohacking Data Project release: v1.5.0