Red light and near-infrared are neighbouring bands of the same spectrum. Red is visible, and LED masks usually list it at about 620 to 660 nm; near-infrared starts just past what the eye can see, and masks usually list it at about 800 to 880 nm. In practice the differences are that you can see one and not the other, and that the longer wavelength travels further below the surface of the skin.
Where they sit on the spectrum
Visible light runs from violet at roughly 380 nm to deep red at roughly 700 to 750 nm. Past that, the eye stops responding, and the light is called infrared. The part closest to visible red is near-infrared. LED masks use a few narrow bands within this range, and each band is named by its peak wavelength in nanometres.
| Band | Range masks commonly list | Visible? | Absorbed |
|---|---|---|---|
| Blue | About 405–470 nm | Yes | Closest to the surface |
| Amber / yellow | About 585–595 nm | Yes | Near the surface |
| Red | About 620–660 nm | Yes, deep red | Further below the surface |
| Near-infrared | About 800–880 nm | Little or none | Furthest of the four |
A mask's listing should give a number for each mode. "Red light" or "infrared" without a figure is a description, not a specification.
What "deeper" means, and what it doesn't
Light that reaches the skin is partly scattered and partly absorbed. The pigments near the surface absorb shorter wavelengths more strongly, so blue is used up close to the surface. Red gets further. Near-infrared gets further still, because less of it is absorbed on the way.
That is the whole of the physical difference, and it is easy to overstate. Depth is a property of the light, not a result. A wavelength that travels further does not do more because of it, and no mask can show you what is happening below the surface. If a listing turns "deeper" into a promise about what will change, it has moved from physics to marketing.
Why near-infrared LEDs look switched off
Switch a mask to a near-infrared mode and many of the LEDs will look dark, or show a dull red glow. That is expected. LEDs around 850 nm usually leak a little visible red at the edge of their output, so you see a faint glow. LEDs at longer near-infrared wavelengths may show nothing at all.
This catches people out in two ways. Some assume the mask is faulty. Others assume a dim LED is a harmless one. Neither is a safe assumption. Some phone cameras pick up near-infrared as a pale glow, which is a reasonable way to check the LEDs are on: point the camera at the inside of the mask, with the mask facing away from you, rather than looking into it yourself.
Why eye care is different for each
Bright visible light triggers a reflex. You squint, blink or look away, and that reflex limits how much light reaches the eye. Red triggers it. Near-infrared does not, because you cannot see it. So with near-infrared, "it doesn't look bright" tells you nothing about how much light is reaching your eyes.
The rules are the same for both: keep your eyes closed for the whole session, wear the included eye protection, and do not look into the LEDs, including when the mask is switched on and off your face. The reasons behind each rule are in LED mask eye safety, and the full list, including who should ask a doctor first, is on the safety page.
Why masks pair them
Many masks run red and near-infrared together in one mode. The practical reason is simple: one session covers both wavelengths, so the routine stays the same length. Pairing them does not double anything. It lights two sets of LEDs at the same time.
Near-infrared is also often confused with heat. Heat lamps and infrared saunas run at far higher power than an LED mask. A mask's near-infrared LEDs are low-power light sources, and the mild warmth you feel comes from the LEDs themselves and from the mask resting against your skin. A mask should never feel hot; if it does, stop and take it off.
What to check on a spec sheet
- A number for every mode. Red at a stated wavelength, near-infrared at a stated wavelength. If near-infrared is listed without a figure, ask for one.
- How near-infrared is offered. On its own, combined with red, or not at all. All three exist, and the listing should say which.
- Session length and auto-off. The manufacturer sets these for the mask's LEDs. A mask without auto-off leaves the timing to you.
- Eye protection in the box. Goggles or eye shields, not just a cut-out.
- A manual that states frequency and warnings. If the warnings are missing, the rest of the documentation is worth questioning too.
For reference, the Folliqen LED Mask lists red 620–630 nm, green 520–525 nm, blue 440–465 nm and near-infrared 850 nm, with these modes: red, near-infrared, blue, green, yellow, purple, cyan and white. The mode guide sets out what each one is designed for, and what the colours on an LED mask are for covers the other colours you will see on masks.
Questions people actually ask
Is near-infrared the same as infrared heat?
No. Heat lamps and infrared saunas run at far higher power. The near-infrared LEDs in a mask are low-power light sources. Mild warmth is normal; heat is a reason to stop.
Should I use red or near-infrared?
If the mask has a combined mode, that is the simplest choice, because one session covers both. Otherwise start with red, keep to it for a few weeks, and follow the frequency in the manual; there is more on that in how often to use an LED mask. Neither mode is designed for a skin condition; for that, see a dermatologist.
Is one safer for the eyes than the other?
Both need the same care: eyes closed and eye protection on. Near-infrared needs more attention, not less, because your eyes do not react to it.
If you want to try one: Folliqen LED Mask, $99, 10 minutes a session, 30 days to decide.