Product pages for LED masks are full of numbers: 630nm, 660nm, 850nm, "7 colors". Here is what those numbers mean in plain English, and what they don't tell you.
What "nm" means
Light is described by its wavelength, measured in nanometers (nm). Different wavelengths look like different colors to us. Roughly speaking, about 450nm looks blue, about 520nm looks green, and 620 to 700nm looks red. Above about 750nm you are in near-infrared, which the human eye cannot really see.
630nm vs 660nm: both red
630nm and 660nm are both visible red light; 660nm is a slightly deeper red. Masks and panels pick different red wavelengths, and both are common in at-home LED devices. LumaMask uses 630nm red. Our body device, LumaBelt, uses 660nm red.
850nm: near-infrared is different
850nm is near-infrared. It is invisible (you may see a faint glow from the LED itself) and is often marketed for body devices rather than face masks. Here is the honest part: LumaMask does not include near-infrared. If a product page doesn't clearly list an infrared wavelength in its specs, assume it doesn't have one. LumaBelt combines 660nm red with 850nm near-infrared.
What about the other colors?
Many masks, LumaMask included, offer extra modes such as blue, green, purple, yellow, cyan and white. These are additional light settings you can choose from. Most people build their routine around red light and treat the others as options.
What the wavelength doesn't tell you
- Coverage: how many LEDs, and do they cover the neck?
- Fit: a flexible mask stays closer to the skin than a rigid shell that floats above it.
- Session design: is there a timer, and how long are sessions?
- Honesty: does the brand clearly say which wavelengths are and aren't included?
The bottom line
A wavelength number tells you the color of the light, nothing more. Look for clear specs, a comfortable fit and a routine you'll enjoy. LED masks are cosmetic wellness devices, not medical treatments, and experiences vary.
Curious about the difference on the body side? Read 660nm vs 850nm: Red Light vs Near-Infrared, Explained Simply.