Laser vs LED Red Light Therapy: Which Is Better?

Photobiomodulation, the umbrella term for therapeutic red and near-infrared light, is delivered in two quite different ways. Large LED arrays and beds treat broad areas at relatively low intensity. Laser probes deliver concentrated light to a small, specific point.

They are not competing versions of the same thing, and the choice between them is mostly determined by what you are treating and how deep it sits.

What is photobiomodulation therapy?

Photobiomodulation therapy, often shortened to PBM, is the use of red and near-infrared light at low intensity to influence how cells function. Light at these wavelengths is absorbed inside the cell, chiefly by the mitochondria. A 2017 review in AIMS Biophysics identifies cytochrome c oxidase as the primary chromophore and reports increased cellular energy (ATP) production, lower levels of reactive oxygen species in oxidatively stressed cells and an overall reduction in inflammation as among the most reproducible effects.

The important word is low. Photobiomodulation does not cut, burn or heat tissue to produce its effect. It is the term now preferred in the research literature, and it covers both of the delivery methods compared in this article.

Low level laser therapy and cold laser therapy: are they the same?

Yes. Low level laser therapy, usually abbreviated to LLLT, and cold laser therapy are older names for photobiomodulation delivered with a laser. "Cold" simply means the laser does not heat tissue, in contrast to the surgical lasers used to cut or ablate.

Photobiomodulation replaced both terms because "low level" was never clearly defined and because LEDs, which are not lasers, are now widely used too. A 2018 review in Photochemical and Photobiological Sciences notes that some authors once insisted lasers were essential, but that LED photobiomodulation is here to stay. If a clinic advertises LLLT, cold laser or PBM laser treatment, it is describing the same category of treatment. What distinguishes one provider from another is the device, the dose and the clinical reasoning, not the label.

The difference between LED and laser

Both deliver light at therapeutic wavelengths. The difference is in how that light behaves.

LEDs emit light that spreads as it travels and covers a wide area. Power is distributed across that area, so intensity at any one point is comparatively low. This suits treating large regions.

Lasers emit coherent, collimated light: the waves stay in step and the beam stays tight rather than spreading. That concentrates energy into a small area, allowing more to be delivered to a specific point, and generally achieving greater depth.

A useful analogy is a floodlight versus a torch beam. Both illuminate. One covers the garden, the other reaches the end of it.

Red light vs near-infrared: wavelengths explained

Light is measured by wavelength in nanometres (nm). A 2009 review in Dose-Response notes that low level light therapy almost exclusively uses red and near-infrared light of about 600 to 1,100 nm, within an optical window where tissue absorbs and scatters light less, and that water absorbs infrared light above about 1,100 nm.

• Red light sits at roughly 620 to 700 nm, with 630 to 670 nm common in therapy devices. It is visible as a deep red glow and is absorbed mainly in the skin and just below it.
• Near-infrared light sits beyond what the eye can see, from about 700 nm upwards, with 800 to 850 nm common in therapy devices. It passes deeper, towards muscle, tendon and joint tissue.

Neither is better in general. Red suits skin and superficial targets; near-infrared suits deeper ones. Many clinical systems combine both so that one session covers superficial and deeper tissue. Infrared light therapy in this sense is not the same as an infrared sauna, which works by heating the body.

Why depth matters

Light does not penetrate tissue uniformly. Different wavelengths reach different depths, and the amount of light reaching a given depth falls off sharply.

Red light is generally considered to be absorbed more superficially, which is why it is discussed in relation to skin. Near-infrared is generally considered to penetrate further, which is why it is used for deeper tissue.

This is the practical crux. A superficial target can be reached by a broad LED array. A deeper structure, such as a joint, generally requires the concentration a laser provides. Treating a deep target with a device that cannot reach it means the tissue you care about receives very little.

Where each fits

Full-body LED systems

Best suited to treating large areas at once: general recovery after training, widespread muscular soreness, or where the objective is broad coverage rather than one specific point.

The practical advantage is coverage and consistency. In a full-body system the distance between the LEDs and your skin is fixed by the design, so the dose is controlled rather than estimated. Sessions are short and passive.

Laser probes

Best suited to a specific, localised target, particularly a deeper one. A clinician places the probe directly over the structure being treated and delivers a defined dose to that point.

Treatment is hands-on and targeted, and typically forms part of a wider treatment session rather than standing alone.

Using both

Where a person has both a specific local problem and a broader recovery need, the two are complementary. A laser addresses the particular structure; a full-body session addresses general recovery. Neither substitutes for the other.

What is LED light therapy? Face masks, panels and beds

LED light therapy is a broad label. It covers at least three quite different kinds of device.

• LED face masks and handheld devices. Low-powered, designed for the skin of the face, and used mainly for cosmetic goals such as skin tone and mild acne. They treat a small, superficial area.
• LED panels. Flat arrays used at home or in clinics for a region of the body. Output varies enormously between products, and the dose depends on how far you stand from the panel.
• Full-body LED beds. Clinical systems such as the NovoTHOR surround the body with a large array of LEDs at a fixed distance, delivering a controlled whole-body dose in a single short session.

All three use LEDs, but they are not interchangeable. A face mask will not do the job of a bed, and a bed is not the tool for treating one small patch of skin.

LED light therapy colours: red, blue, green and yellow

Cosmetic LED devices often offer several colours, and they do different things:

• Red and near-infrared: the wavelengths used in photobiomodulation, discussed for skin quality, tissue repair, pain and recovery.
• Blue (around 415 nm): used for acne at the skin surface. A 2023 systematic review in Photodermatology, Photoimmunology and Photomedicine found red and blue LED light effective for acne. Blue light does not penetrate deeply and is sometimes combined with red.
• Green and yellow: marketed for pigmentation and redness, but the evidence is much more limited.

Full-body photobiomodulation, such as the NovoTHOR bed, uses red and near-infrared light rather than blue. For skin concerns specifically, see red light therapy at Omnia.

Laser therapy for pain: class 3B and class 4 lasers

Lasers are classified by output power, and two classes are used for pain and tissue repair.

Class 3B lasers have an output of up to 500 milliwatts, according to UK Health Security Agency laser safety advice. They are the devices on which most low level laser therapy research was carried out, and they produce no meaningful heating. Low level laser probes of the kind used for photobiomodulation, including THOR probes, are typically in this class.

Class 4 lasers exceed 500 milliwatts, and the UK Health Security Agency notes that direct viewing of the beam and skin exposure are hazardous. They are sometimes marketed as high-intensity or high-power laser therapy. They deliver a dose faster and produce noticeable warmth, which means the operator has to keep the beam moving to avoid overheating the skin.

Higher power is not automatically better. Because photobiomodulation follows the dose-response curve described below, what matters is the total dose reaching the target tissue, not the class printed on the device. Knee osteoarthritis has some of the strongest evidence: a 2019 systematic review in BMJ Open found that low-level laser therapy reduced pain and disability, with larger effects at recommended doses. Effects are generally modest and build over a course of sessions.

Dose is the thing that determines whether it works

The most consequential principle in photobiomodulation, and the most frequently ignored.

Effects appear to follow a biphasic dose-response, described in reviews in Dose-Response (2009) and AIMS Biophysics (2017), in which low doses stimulate and high doses inhibit. There is a range in which effects are observed, and exceeding it does not increase the effect and may reduce it. Too little does nothing. Too much can be counterproductive.

This is why professional practice specifies wavelength, power, treatment area, distance and duration, rather than simply treating for as long as feels reasonable.

It also explains a common experience with consumer devices. A device whose real output is far below its advertised figure delivers a dose below the effective range, and the user concludes that photobiomodulation does not work, when what actually happened is that they never received a therapeutic dose.

On the size of the evidence base

Photobiomodulation has been studied extensively. A 2009 review in Dose-Response counted more than 100 randomised, double-blind, placebo-controlled trials and over 1,000 laboratory studies, alongside animal work.

Two honest caveats about that literature.

First, quantity is not quality. It includes a great deal of small, methodologically limited work alongside better-designed trials.

Second, and more practically: because dose parameters vary so widely between studies, results are genuinely inconsistent, and much of that inconsistency is thought to reflect differences in dose rather than the treatment failing outright. Studies delivering doses outside the effective range would not be expected to show an effect. The 2009 Dose-Response review notes that the complexity of choosing light parameters has led to a number of negative studies as well as many positive ones.

The applications with the more established evidence include certain musculoskeletal pain presentations, such as knee osteoarthritis. Photobiomodulation is also used in some oncology settings, under specialist supervision, to manage side effects of cancer treatment: 2019 MASCC/ISOO guidelines support specific protocols to prevent oral mucositis in some patients.

Where you should be sceptical is the broad wellness marketing, which frequently cites the overall size of the literature as though it constituted proof for whatever specific claim is being made.

Red light therapy at home: how home devices compare

Home red light therapy devices have improved, and for some uses they are a reasonable choice. The main differences from clinical equipment are these:

• Output. Look for independent third-party measurements of irradiance rather than relying on the figure on the box.
• Dose control. With a panel, the dose changes with every few centimetres of distance. Clinical beds fix the distance, and laser probes are applied in contact with the skin.
• Coverage and depth. A small panel or mask treats a small superficial area. It cannot replicate a full-body session or reach a deep joint the way a laser probe can.
• Guidance. A home device comes with generic instructions. A clinic sets wavelength, dose and frequency for the problem being treated, and changes them if you are not responding.

A sensible approach is to use a clinic to establish whether photobiomodulation helps your particular problem, then decide whether a home device is worth buying for maintenance. The safety points below apply at home as well, particularly eye protection and photosensitising medication.

Questions worth asking any provider

• What wavelengths does your device use?
• What is the irradiance, and at what distance was it measured?
• What dose does your protocol deliver, and why that dose?
• Is the device certified, and for what?
• Do you have both broad-area and targeted options, and how do you decide?

A provider who can answer these understands what they are doing. One who answers only with claims about benefits does not.

Safety

Red and near-infrared light is non-ionising and does not carry the DNA-damaging risk associated with ultraviolet light, which Cancer Research UK links to skin cancer. Neither LED nor laser photobiomodulation is comparable to a sunbed.

Laser devices carry specific eye-safety requirements, and appropriate protective eyewear should be used with both. Contraindications include photosensitising medication, active cancer, photosensitive conditions and pregnancy.

Laser and LED questions, answered

Does LED light therapy work?

It can, for the right problem at the right dose. The evidence is strongest for some musculoskeletal pain with red and near-infrared light, and a 2023 systematic review found red and blue LED light effective for acne. Results build over a course and depend heavily on the device's real output, which is why low-powered or poorly made devices often disappoint.

Is laser stronger than LED?

More concentrated rather than simply stronger. It delivers more energy to a small area and generally reaches deeper. For treating a large area, that concentration is not an advantage.

Is it hot?

Therapeutic photobiomodulation operates at low intensity and is not primarily a heating treatment. Mild warmth is common. This is different from high-power surgical lasers, which are an entirely different category.

How many sessions?

Effects are generally cumulative rather than immediate, so a course is typical. A single session is not a fair test.

Can I get the same result at home?

For a small superficial area, a good home device used correctly may be reasonable. For depth, for large areas, or where dose accuracy matters, clinic equipment differs substantially.

Does it hurt?

No. Most people feel nothing, or mild warmth.

Getting the right device for your problem

Not sure whether your problem needs broad LED coverage or a targeted probe? At Omnia a clinician can help you decide between a NovoTHOR full-body session (£70 for 20 minutes) and a THOR Laser session (£80 for 30 minutes). Book online, phone 020 4515 0000 or visit 8 to 9 Bedford Corner, The Avenue, Chiswick W4 1LZ.

Sources

• AIMS Biophysics: Mechanisms and applications of the anti-inflammatory effects of photobiomodulation (Hamblin, 2017)
• Dose-Response: Biphasic dose response in low level light therapy (Huang and others, 2009)
• Photochemical and Photobiological Sciences: Photobiomodulation, lasers vs. light emitting diodes? (Heiskanen and Hamblin, 2018)
• UK Health Security Agency: Laser radiation, safety advice
• BMJ Open: Efficacy of low-level laser therapy on pain and disability in knee osteoarthritis, systematic review and meta-analysis (Stausholm and others, 2019)
• Photodermatology, Photoimmunology and Photomedicine: Utilization of light-emitting diodes for skin therapy, systematic review and meta-analysis (Ngoc and others, 2023)
• Supportive Care in Cancer: Systematic review of photobiomodulation for the management of oral mucositis in cancer patients and clinical practice guidelines (Zadik and others, 2019)
• Cancer Research UK: Sunbeds and cancer

This article is general information, not medical advice. If you have a medical condition or take regular medication, discuss photobiomodulation with your doctor first.