The technology
How LED light therapy works
LED light therapy is easier to understand than most marketing makes it sound. Here is the technology, described plainly — what it is, what it is not, and what to look for.
Light is measured in wavelengths
All light can be described by its wavelength, measured in nanometres (nm). The visible spectrum runs from roughly 400 nm at the blue end to around 700 nm at the red end. Anything longer than that — near-infrared — is largely invisible to the human eye, though it is still light.
When a skincare device describes itself as red, blue or near-infrared, it is describing which part of that spectrum its diodes emit. That is the entire claim being made by the colour on the box.
What an LED actually is
An LED — light-emitting diode — is a small semiconductor that produces light within a narrow band of wavelengths when current passes through it. LEDs are efficient, run relatively cool and can be arranged in large arrays, which is why they suit face masks and panels.
LED skincare devices do not use UV light, and they are not lasers. A laser concentrates light into a tight, coherent beam; an LED array spreads light broadly across a surface.
Why distance and time matter
Light spreads out as it travels. A device held further from the skin delivers less light to any given point than the same device held close. This is why mask-style devices, which sit at a fixed distance, are designed differently from handheld or panel devices.
Every device sets its own session length and recommended frequency, based on its own output. Those figures come from the manufacturer and, where confirmed, are shown on each product page — they are not interchangeable between devices.
What to check before you buy
A specification tells you far more than a marketing line. Look for the wavelengths emitted, how many diodes there are, the recommended session length and frequency, whether eye protection is supplied or required, and what the warranty covers.
Also check the practical details: how the device is powered, how it is cleaned, whether it fits comfortably, and whether there are conditions or medications that mean you should speak to a clinician first.
LED beauty devices sold by Ilumi London are cosmetic products. They are not medical devices and are not intended to diagnose, treat, cure or prevent any condition. If you have a skin or health condition, are pregnant, or take photosensitising medication, speak to a qualified clinician before use.