“Light therapy” describes several different treatments. You may encounter the term in discussions about wrinkles, acne, inflammatory skin conditions, newborn jaundice, or seasonal depression.
These treatments do not all use the same wavelengths, devices, or biological mechanisms. Understanding the differences helps you evaluate claims and choose an appropriate treatment for your concern.
Why the type of light matters
Light exists across a spectrum of wavelengths. Ultraviolet radiation, visible light, and infrared radiation interact with tissues differently.
The effect also depends on the amount of energy delivered, the duration of exposure, and the tissue being treated. A beneficial result from one carefully controlled protocol does not establish that another light source will produce the same effect.
More exposure is not automatically better.
Red and near-infrared photobiomodulation
Photobiomodulation uses selected light exposures to influence biological activity without intentionally burning or removing tissue.
Red and near-infrared wavelengths are used in many devices studied for skin appearance, tissue responses, and other applications. Researchers have investigated mechanisms involving cellular signaling and mitochondrial activity.
However, a proposed mechanism is different from a demonstrated patient benefit. Evidence should be relevant to the specific device, protocol, and treatment goal.
Blue light for acne
Some acne-treatment devices use blue light to act on molecules produced by acne-associated bacteria. Certain systems combine blue and red light.
This is different from red light therapy alone and different from ordinary screen exposure. A device designed for wrinkle treatment should not automatically be assumed to treat acne.
Other medical uses of light
Dermatologists may use ultraviolet phototherapy for selected conditions, including psoriasis and vitiligo. These treatments require appropriate dosing and medical supervision.
Photodynamic therapy combines a photosensitizing medication with a light source for specific medical indications.
Blue-light treatment for newborn jaundice and bright-light treatment for seasonal affective disorder are additional examples with distinct purposes. They should not be listed as evidence that an aesthetic LED device provides the same benefits.
Light therapy does not replace sun protection
A controlled therapeutic exposure is different from unprotected sunlight. Red light treatment does not provide sunscreen protection or cancel out ultraviolet damage.
Continue appropriate sun protection and follow the instructions for any medications or procedures that affect light sensitivity.
Choosing a treatment
Ask which wavelengths the device uses, what it is intended to treat, and what evidence supports that use. Confirm the recommended schedule, eye protection, and any precautions relevant to your health history.
At Modern Aesthetics in San Jose, I consider red light therapy as one possible part of an individualized skin plan. The goal is to select a treatment with a clear purpose and realistic expectations.
Schedule a consultation to discuss whether it has a useful role for your skin.
Updated October 23, 2026.