Laser or LED? What the science actually says.
For years, practitioners were taught that lasers are the gold standard for photobiomodulation. The peer-reviewed evidence tells a more interesting story. Here is what the research shows about how red and near-infrared light actually works, and why the light source matters less than most people were led to believe.
Same wavelengths, different delivery
Switch between the two sources. The coherence and the shape of the beam differ. The therapeutic wavelength that reaches the cell is the same.
Laser
- Single pure wavelength (monochromatic)
- Coherent, light waves in step with each other
- Collimated into a tight, focused beam
- Treats a small, concentrated spot
- Requires a laser safety class and protective eyewear
Both deliver the wavelengths cytochrome c oxidase absorbs. That absorption, not coherence, is what research associates with the therapeutic effect.
Where the idea that laser is better came from
Photobiomodulation began in the 1960s, just after the laser was invented, and for its first several decades nearly all of the research used lasers. The therapy was even named low level laser therapy.
Because the studies used lasers, the field assumed the benefit depended on laser-specific properties: a single pure wavelength, light waves in step with each other, and a tight focused beam. That assumption was reasonable at the time. It was also never really proven.
What actually drives the effect
Research indicates the primary target of red and near-infrared light in the body is cytochrome c oxidase, or CCO, an enzyme in the mitochondria, the part of the cell that produces energy. When light of the right wavelength reaches CCO, it is associated with promoting electron transport, which is associated with increased mitochondrial activity and ATP, the energy currency of the cell. This is the leading, most-studied explanation for how photobiomodulation works.
The key point is simple. What matters is that the right wavelength reaches the photoacceptor. That absorption is not exclusive to laser light. Non-coherent light from LEDs delivers the same therapeutic wavelengths and can initiate the same beneficial cellular response. The field adopted the broader name photobiomodulation in part to reflect that a laser is not essential to the benefit.
The coherence debate, presented fairly
For more than 30 years, researchers have debated whether coherence is required. Some argue that coherent laser light penetrates bulk tissue better, and that laser speckle patterns might stimulate mitochondria in a particular way. Others, and a growing body of work, conclude that photobiomodulation is fundamentally a photobiological effect driven by light absorption, so coherence is not required for therapeutic benefit.
Both sides deserve an honest hearing. The weight of current evidence supports the view that the effect does not depend on lasers or coherence.
What the comparison studies show
An honest caveat first. Many head-to-head comparisons are limited, because the laser and LED groups often used different wavelengths, power levels, or spot sizes, which makes a clean comparison difficult. With that stated, the referenced review looked at roughly 40 newer studies across animal models, cell cultures, and human trials. The overall pattern:
Animal studies
Wound healing, nerve and bone repair, inflammation, arthritis, burns
Both LED and laser were frequently effective. Most showed similar benefits, and where one had an edge in a specific context it went in both directions, including cases where LED performed better.
Cell culture studies
Fibroblast proliferation, wound closure, and related processes
Mixed results. Some favored laser in specific cases, others found laser and LED comparable, and both produced significant effects.
Human clinical trials
Jaw disorders, oral mucositis, knee osteoarthritis, orthodontic pain, post-surgical recovery
Outcomes varied, with many finding no significant difference between laser and LED, and some finding LED effective or more pronounced in specific cases.
Laser and LED, side by side
The physics differ. The therapeutic wavelength that reaches the cell does not.
| Property | Laser | LED |
|---|---|---|
| Wavelengths delivered | Single pure wavelength | The same useful wavelengths (quasi-monochromatic) |
| Coherence | Coherent | Non-coherent, which is not required for the effect |
| Beam | Collimated, tight focused spot | Broad, even coverage |
| Treatment area | A small spot at a time | A large area in one session |
| Safety class | Laser safety class, eyewear, restricted room | No laser safety class required |
| Cost per milliwatt | Higher | Far lower |
| Hands-free, delegated, at-home use | Limited | Practical |
| Effect on photobiomodulation | Effective | Effective |
Why LED makes practical sense for a practice
Beyond the science, LED offers concrete advantages that matter in a real practice.
- No laser safety class, no protective eyewear protocols, and no restricted-room requirements.
- Treats a large area at once instead of a small focused spot, so sessions are faster and more consistent.
- Far lower cost per milliwatt, which is what makes a strong return on investment possible.
- Practical for hands-free, delegated, and at-home use.
These are not small differences in a busy practice. They are the difference between a modality that is easy to run every day and one that is not.
The Source
Read the evidence yourself
Everything here is grounded in the peer-reviewed literature. Read the paper this page draws on.
The honest bottom line
The current weight of evidence supports a clear conclusion. Photobiomodulation is not dependent on lasers or on coherence. Quasi-monochromatic LED devices deliver the wavelengths the body responds to and can produce meaningful physiological effects.
The laser versus LED debate is not fully closed, and the research community rightly calls for more high-quality head-to-head studies. But the old assumption, that you need a laser to get the benefit, is not supported by the science. For a modern practice, clinical-grade LED offers the evidence base and the practical advantages that make photobiomodulation genuinely workable.
See it in a clinical-grade LED device
The FlashHeal puts this evidence to work in a practice, hands-free and verified. Talk it through with our team, or read the paper first.
Read the peer-reviewed paper