Short answer: 660nm (red) light works on the skin’s surface, while 850nm (near-infrared) penetrates deeper into muscle and joint tissue. Most people are best served by a panel that offers both, so you can target surface and deeper areas from one device.
What is 660nm red light?
660nm sits in the visible red part of the spectrum. It is absorbed close to the skin’s surface, which is why it is the wavelength most associated with skin and complexion uses. You can see it — it is the bright red glow.
What is 850nm near-infrared?
850nm is near-infrared, just beyond what the eye can see. It penetrates further into the body, reaching muscle and joint tissue, which is why it is the wavelength most associated with deeper, below-the-surface use.
Do you need both?
For most home users, yes — 660nm and 850nm together cover the widest range of uses from a single session. If a panel only offers one, you are limited to either surface or deeper coverage. This is why “660 + 850” is the baseline combination to look for.
What about the other wavelengths?
Some panels add more — 480, 630, 810, 830 and 1060nm. These give extra flexibility (Dermfix RLF panels offer all seven, selectable from the controller), but they are a “nice to have.” Strong, honest output at 660 and 850 matters more than a long wavelength list.
FAQ
Is 660nm or 850nm better?
Neither — they do different jobs. 660nm for the surface, 850nm for deeper tissue. The best setup uses both.
Can I see near-infrared light?
No. 850nm is invisible; panels usually add a faint visible red so you can tell it is on.
Do more wavelengths mean a better panel?
Not necessarily. Measured output and build quality matter more than the number of wavelengths.