Last updated: July 2026 · Written by the Dermfix phototherapy team
Short answer: After reviewing 68 in vitro and animal studies, researchers found that LED light produces the same core biological effects on wound healing as laser light — less inflammation, more fibroblast activity, more collagen, and better blood vessel formation. The property that makes a laser a laser (coherence) doesn't appear to be what makes low-level light therapy work. Wavelength and dose matter far more than whether the light source is a laser or an LED.
The review
A team from the Universidade Federal de Minas Gerais and Pontifícia Universidade Católica de Minas Gerais in Brazil — Maria Emília de Abreu Chaves, Angélica Rodrigues de Araújo, André Costa Cruz Piancastelli, and Marcos Pinotti — set out to settle a long-running debate in low-level light therapy: does it actually matter whether you use a laser or an LED? The review was published in the Anais Brasileiros de Dermatologia in 2014.
The team searched Medline, PubMed, Science Direct and SciELO for studies published between 1992 and 2012, using combinations of terms like “low level laser therapy,” “LED,” “phototherapy,” “wound healing,” “fibroblast,” “collagen” and “angiogenesis.” They ended up analyzing 68 studies: 48 on laser light alone, 14 on LED light alone, and 6 that directly compared the two on the same wounds.
What both light sources actually do
Across the laser studies, wavelengths ranged from 532 to 1064nm, with 632.8–830nm being the most commonly used band, and doses mostly falling between 1 and 5 J/cm². The LED studies used a similar range, 456–880nm, most often clustering around 627–670nm, with 4 J/cm² as the most common dose.
Despite coming from different light sources, both produced the same list of biological effects: fewer inflammatory cells at the wound site, more fibroblast proliferation, more collagen synthesis, and increased angiogenesis and granulation tissue formation — the core building blocks of wound repair. The six studies that tested laser and LED head-to-head on the same wound models reported no meaningful difference between them.
Why coherence turns out not to matter
Laser light's defining physical property is coherence — its photons travel in the same frequency, direction, and phase. Some researchers have argued this gives lasers an edge that non-coherent LED light can't match. This review pushes back on that idea directly: coherence is lost almost immediately once light interacts with biological tissue, and the reviewed evidence shows the cellular response to light doesn't depend on whether that light started out coherent. In practical terms, once the light hits skin, a laser and an LED at the same wavelength are behaving similarly at the cellular level.
What actually does matter: wavelength and dose
If coherence isn't the deciding factor, what is? The review points squarely to two parameters: wavelength and dose.
On wavelength, the majority of effective studies — 59 of the 68 reviewed — used light within what the authors call the “optical therapeutic window,” roughly the red-to-near-infrared range, where hemoglobin and melanin absorb the least and light penetrates tissue most efficiently. A smaller number of studies used blue or green light and still saw effects, but red and near-infrared remain the dominant, best-supported choice for wound applications.
On dose, the review references the Arndt-Schultz curve — the same biphasic dose-response principle seen elsewhere in this literature — where very low doses produce little effect, effects build toward a peak around the 1–5 J/cm² range, and doses pushed too high (10–16 J/cm² in several studies) actually inhibited the biological response rather than enhancing it. Getting the dose right, in other words, matters more than which device delivered it.
The proposed mechanism
The review outlines a two-stage model (attributed to researcher Tiina Karu) for how this works at the cellular level. First, a “primary reaction”: light is absorbed by cytochrome c oxidase in the mitochondria, altering its redox state and speeding up electron transport in the respiratory chain — happening within seconds to minutes. This is followed by “secondary reactions” that unfold over hours to days, where that initial signal is amplified and transmitted throughout the cell, ultimately affecting calcium levels, metabolism, DNA and RNA synthesis, and fibroblast proliferation — the downstream effects that actually drive visible wound healing.
Frequently asked questions
So is LED just as good as laser for wound healing?
Based on this review of 68 studies, yes — the biological effects were consistently similar, and the six head-to-head comparisons found no significant difference between them.
Why did people think lasers were better in the first place?
Mainly because of coherence — the theory that laser light's uniform phase gives it a therapeutic edge. This review found that assumption doesn't hold up once light actually interacts with tissue.
What matters more than the light source?
Wavelength (red-to-near-infrared performed best) and dose (with effects peaking around 1–5 J/cm² and higher doses becoming counterproductive).
Does this mean any wavelength or dose works equally well?
No — the review is explicit that effects are highly dependent on getting both parameters right, which is why the authors call for more standardized clinical protocols.
Sourced from: Chaves, M.E.A., Araújo, A.R., Piancastelli, A.C.C. & Pinotti, M. “Effects of low-power light therapy on wound healing: LASER x LED.” Anais Brasileiros de Dermatologia, 89(4), 616–623 (2014). DOI: 10.1590/abd1806-4841.20142519.
Disclaimer: this article summarises published research for general information. It is not medical advice and does not describe the intended purpose of any Dermfix product.