At-home skin devices come with a lot of technical vocabulary. This glossary explains terms you will see on product pages and in LEDFacialMask.org guides about LED face masks, red light therapy and microcurrent tools.
The definitions describe what words mean, not what a device does for any person. This site makes no claims about results, and specifications vary by manufacturer, so check the maker’s published details for a particular product.
- Auto shut-off
- A feature that turns a device off automatically after a set time. It is usually tied to the session timer.
- Blue light
- Visible light in roughly the 400 to 495 nanometer range. Some LED masks include blue diodes alongside other colors, and manufacturers list which wavelengths a device uses.
- Conductive gel
- A water-based gel that some microcurrent devices ask users to apply between the device and the skin. Manufacturers state whether a particular product needs it.
- Continuous mode
- An output setting where the light stays on steadily for the whole session. It contrasts with pulse mode, where the output switches on and off.
- Diode
- A small electronic component that lets current flow in one direction. In an LED mask, the diodes are the individual light-emitting parts, and listings often state how many there are.
- FDA clearance
- A regulatory status the U.S. Food and Drug Administration grants to certain devices after review. It is a classification, not a promise about what a device will do for a particular user.
- Fitzpatrick scale
- A six-type classification of how skin reacts to sun exposure, developed for dermatology. Some product instructions refer to it when describing who a device is intended for.
- Fluence
- The amount of light energy delivered to a surface over a period of time, usually measured in joules per square centimeter. It combines power density with session length.
- Handheld device
- A compact tool held by the user and moved or placed on the face. Many microcurrent tools and some light devices are handheld rather than worn.
- Irradiance
- The power of light reaching a surface, expressed in milliwatts per square centimeter. Listings sometimes give it as power density.
- LED
- Short for light-emitting diode, a semiconductor that produces light when current passes through it. LEDs can be built to emit a narrow range of colors.
- Microcurrent
- A very low level of electrical current, measured in millionths of an ampere. Microcurrent tools deliver current through metal contacts, and each manufacturer publishes its own specifications.
- Milliamp (mA)
- A thousandth of an ampere, a unit used to describe electrical current. Microcurrent figures are normally a small fraction of one milliamp, so the unit shown on a spec sheet matters.
- Nanometer (nm)
- One billionth of a meter, the unit used to state a light’s wavelength. Red light is often listed around 620 to 700 nm.
- Near-infrared (NIR)
- Light just beyond the red end of the visible spectrum, invisible to the eye. Devices that include it list the wavelength in nanometers.
- Patch test
- A small trial of a product or device on a limited area before wider use, often recommended in manufacturer instructions. Follow the guidance that came with your device.
- Power density
- The amount of light power per unit of surface area, often given in milliwatts per square centimeter. It is another name for irradiance in many product listings.
- Pulse mode
- A setting where the light switches on and off in a repeating pattern. Manufacturers describe the pattern in their manuals.
- Rechargeable battery
- A battery that can be recharged many times instead of being replaced. Cordless masks and handheld tools commonly use one, with charge time and use time listed by the maker.
- Red light
- Visible light in the red part of the spectrum, usually about 620 to 700 nanometers. It is among the colors most often found in LED masks.
- Red light therapy
- A term for using red and sometimes near-infrared light on the body. It is a name for a type of device use, and this site makes no claims about outcomes.
- Session timer
- A built-in countdown that sets how long a device runs once started. Timer lengths differ between products.
- Silicone mask
- A flexible mask whose LEDs are set into soft silicone so it can curve around the face. Rigid masks use a hard shell instead.
- USB-C
- A common connector type used for charging and power. Many rechargeable skin devices charge through a USB-C port.
- Wavelength
- The distance between peaks of a light wave, which determines its color. It is measured in nanometers and is among the most frequently listed specifications for LED masks.
If you need a term that isn’t listed, email editorial@ledfacialmask.org. The FAQ answers common questions about the site.