Red and near-infrared wavelengths: what the numbers mean

Nanometres describe wavelength, not effectiveness

A nanometre (nm) is a unit of length used to describe light. On a product page, numbers such as 630, 660, 810, 830 or 850 nm identify nominal wavelengths emitted by the device. They do not tell you how much light reaches a target, how evenly it is distributed, or whether a studied clinical protocol has been reproduced.

Red and near-infrared

A 2024 clinical review describes the red region commonly used in photobiomodulation as 620–700 nm and near-infrared as 700–1440 nm. Red light is visible; near-infrared is not visible to the human eye.

These boundaries are practical conventions. A broad band label is not evidence that all wavelengths inside it are interchangeable, and a panel with more listed wavelengths is not automatically more effective.

Why wavelength still matters

Wavelength affects which molecules absorb light and how light behaves in tissue. Reviews discuss cytochrome c oxidase and ion-channel pathways among proposed mechanisms, but the biological response also depends on dose and context.

For a useful protocol, wavelength has to be read alongside:

• optical output and how it was measured;
• distance from the source;
• exposure time and treatment frequency;
• illuminated area and uniformity;
• pulse settings, if any;
• the tissue, outcome and population studied.

Reading a product specification

Treat a manufacturer wavelength list as an identity specification, not clinical proof. Then ask whether output data includes a distance and instrument. “Irradiance” values from a solar power meter and a spectroradiometer can differ materially, so numbers without matching conditions should not be ranked side by side.

PLT keeps each product’s wavelength list in canonical data with its source and checking date. We do not infer wavelength proportions or spectral output that the manufacturer did not publish.

Learn how PLT compares Australian panels →

Sources and references

1. Jalal Maghfour et al.. Photobiomodulation CME part I: Overview and mechanism of action. Journal of the American Academy of Dermatology. 2024-11. DOI: 10.1016/j.jaad.2023.10.073. PMID: 38309304. Accessed 2026-09-07.
2. Michael R. Hamblin. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophysics. 2017-05-19. DOI: 10.3934/biophy.2017.3.337. PMID: 28748217. Accessed 2026-09-07.