LED light therapy — known in the research literature as photobiomodulation (PBM) — uses specific wavelengths of visible and near-infrared light to influence skin cells. It is non-thermal, contains no UV, and has been studied for decades, originally in wound healing and later in skin rejuvenation.
How it works
The light is absorbed by cytochrome c oxidase, an enzyme in the mitochondria — the cell's power plants. This raises cellular energy (ATP) and modulates signalling, which in skin can support fibroblast activity and collagen synthesis. The mechanism is well described in the peer-reviewed literature.
The four wavelengths that matter
What counts is not how many colours a device has, but which wavelengths it delivers accurately, and how deep each one reaches:
~415–420nm · Blue
Stays at the surface (epidermis). Targets blemish-causing bacteria and helps regulate excess oil.
~580nm · Amber
Upper-to-mid dermis. Associated with redness, dullness and the visible signs of photo-ageing.
~630–637nm · Red
Reaches the deeper dermis. The most-studied band for collagen renewal, firmness and fine lines.
~830nm · Near-infrared
The deepest-reaching band. Drives elastin and collagen-fibre repair; useful for elasticity and thinner-skinned areas such as the neck.
Irradiance: the number to ask for
Irradiance (mW/cm²) is the power density actually delivered to your skin. Too low and a session does little; it is also the figure most brands omit, treating it as a trade secret. When comparing devices, ask for the treatment-plane irradiance — the dose at the skin — not just a component rating.
Is it safe?
LED light therapy is non-thermal and UV-free. Devices that meet recognised photobiological-safety classifications and biocompatibility testing have strong safety records. Follow the device's instructions and use any supplied eye protection. If you have a medical skin condition, are pregnant, photosensitive, or taking photosensitising medication, check with a qualified professional first.
Frequently asked
Does LED light therapy actually work?
For skin, red and near-infrared light have a substantial peer-reviewed evidence base for collagen, fine lines, firmness and healing; blue light for blemishes. Results build over a course of weeks and vary between individuals.
Which wavelength is best?
It depends on the goal: ~630–637nm red for collagen and firmness, 830nm near-infrared for deeper repair and elasticity, ~415–420nm blue for blemishes, ~580nm amber for redness and tone. Many devices combine several.
Is LED light therapy safe?
Devices meeting recognised photobiological-safety classifications and biocompatibility testing have strong safety records. It is non-thermal and does not contain UV. Always follow the device instructions and use eye protection.
How long until I see results?
Light therapy works as a course, not a single use. In controlled studies, measurable improvement builds week on week, with fuller results around four weeks of consistent use.