Guides / 660nm vs 850nm: red light vs near-infrared, explained
660nm vs 850nm: red light vs near-infrared, explained
Almost every panel lists wavelengths like 660nm and 850nm. What they mean, and which one you actually need.
660nm: visible red
660nm is visible deep-red light. It is absorbed close to the surface, which is why it is most often associated with skin - tone, fine lines, and surface tissue. You can see it clearly, so panels heavy in 660nm look bright red.
850nm: near-infrared
850nm is near-infrared and mostly invisible (you may see a faint glow). It penetrates deeper than red light, which is why it is marketed for muscles, joints, and deeper tissue. A panel can look dim yet still output a lot of 850nm.
Combined panels and other wavelengths
Most modern panels mix 660nm and 850nm to cover both surface and deep targets. Some add 630, 810, 830, or 940nm. More wavelengths are not automatically better - what matters is that the bulk of the output sits in the well-studied 630-680nm and 800-860nm ranges.
Which should you pick?
For skin-focused use, lean toward 660nm. For recovery and deeper targets, prioritise 850nm. Most people pick a combined panel. Filter the database by wavelength and irradiance to match your goal.
FAQ
Is 660nm or 850nm better?
Neither is universally better. 660nm targets the skin surface; 850nm penetrates deeper for muscles and joints. Combined panels cover both.
Why does 850nm look dim?
Near-infrared at 850nm is largely invisible to the eye, so a panel can output a lot of it while looking faint. Brightness is not a measure of NIR power.