The anchor category
How do you choose a red light therapy device? The five specs that decide it.
Wavelengths in nanometres, diode count, irradiance at contact, fit, and session timer. Everything else on the box, including the number of colours and the price, tells you nothing about whether it will work.
Every listing in this category uses the same words. These five specifications are what separate the devices that deliver a dose from the ones that deliver a glow.
1. Wavelength
Red 630 to 660 nm for surface skin, near-infrared 810 to 850 nm for depth, blue about 415 nm for acne. Stated in numbers or it does not count. A colour wheel with no nanometres is a lamp.
2. Diode count and spacing
More diodes, evenly spread, means more energy per minute and no dark patches. A mask with 100 LEDs is a different device from one with 700, whatever the marketing says about 'medical grade'.
3. Irradiance at the distance you will use it
Milliwatts per square centimetre, measured at skin contact for a mask or at 15 cm for a panel. Trials sit roughly in the 20 to 100 mW/cm² range. A number quoted at 'zero distance' with no method is a number someone made up.
4. Fit
Light falls off fast with distance. A silicone mask on the skin delivers far more than a rigid shell that floats a centimetre away, and a belt that wraps beats a panel you have to hold. Fit beats specifications more often than people expect.
5. Timer and eye protection
A device with a fixed session length was designed to a dose. One with no timer was designed to a photo shoot. Eye shields or a documented eye-safety note come with anything bright enough to matter.
Red Light Therapy · Questions people actually ask
Straight answers
Does FDA clearance mean it works?
It means the maker showed the device is as safe as a similar cleared device. It is a safety and marketing threshold, not proof of efficacy, and plenty of good devices skip it.
Is a panel better than a mask?
For the body, yes, more area and more power. For the face, a mask that sits on the skin usually delivers a better dose than a panel across the room.
How much should I spend?
Enough for published specs and a fit that suits your face. Past roughly $200 you are buying build quality and brand, not biology.
Updated 2026-09-06. Nothing here is medical advice. A device is never a substitute for a dermatologist.