Cold Laser Therapy vs Red Light Therapy: Laser or LED?
Cold laser therapy and red light therapy are two names for the same kind of treatment: low-power red or near-infrared light used to affect tissue without heating it. "Cold laser" is the older term and usually means a clinician holding a small laser against a sore joint or tendon for a minute or so per spot. "Red light therapy" usually means LEDs lighting a large area, at home or in a studio. The main review comparing the two sources found that the effect does not appear to depend on the light coming from a laser. What does differ is the area covered, who operates the device, the cost, the eye-safety rules, and which uses have been tested with which source. This article explains what a cold laser is, how a laser differs from an LED, what each has been tested for, and what the laser classes on a label mean.
What is cold laser therapy?
It is low-level laser therapy: a low-power red or near-infrared laser applied to the skin over a painful or injured area. It is called cold because, unlike a surgical laser, it does not heat or cut tissue.
The dose tables published by WALT, the international laser therapy association, describe the typical clinic device: a laser with an output of 5 to 500 mW, held on each point for 20 to 300 seconds, delivering about 4 to 16 joules per point, daily for two weeks or every other day for three to four weeks. WALT. Wavelengths run from about 600 to 950 nm, with red used for surface tissue and near-infrared for deeper tissue. Healthline. Physiotherapists, chiropractors, some doctors and dentists, and many vets offer it.
Is cold laser therapy the same as red light therapy?
In principle, yes. Both are forms of what researchers now call photobiomodulation, and the Cleveland Clinic lists cold laser therapy as another name for red light therapy.
The field renamed itself in 2015. The researchers who proposed "photobiomodulation" said that "laser" no longer fitted, because LEDs and other light sources were being used for the same purpose. Anders 2015, Cleveland Clinic. In everyday use the two terms have drifted apart: cold laser means a clinic treatment for pain, and red light therapy means LEDs for skin and general use. One common mistake is to say that cold laser is near-infrared and red light is red. Wavelength and source are separate things: a laser or an LED can be made at either. What is red light therapy covers the names and the history.
What is the difference between a laser and an LED?
A laser produces light of almost a single wavelength in a beam that can be focused to a small spot. An LED produces a wider band of wavelengths and spreads its light over a wide angle.
| Property | Laser diode | LED |
|---|---|---|
| Band of wavelengths | A few nanometres or less | A few tens of nanometres |
| Beam | Can be focused to a small spot | Spreads over a wide angle |
| Coherence (light waves in step with one another) | High | Low |
| Area covered | One small spot at a time | Arrays light a large area at once |
| Cost per milliwatt | Higher | About a hundred times lower |
Sources: the RP Photonics Encyclopedia on laser diodes and LEDs, and Heiskanen and Hamblin 2018.
Is a laser better than an LED for light therapy?
It has not been shown to be. The main review of the question found that the evidence "appears to support the idea that photobiomodulation is not dependent on lasers or coherence".
That review, published in 2018, collected the animal and human studies that had tried both sources. In most of them the laser and the LED gave similar results. The authors added that the quality of the comparisons was low, because wavelength and dose were rarely matched, and that more head-to-head trials are needed. Heiskanen and Hamblin 2018. A 2022 review of 18 dental studies reached a similar view, finding diode lasers and LEDs equally effective, although most of the studies it covered tested only one of the two. Lesniewski 2022.
So the useful questions about a device are its wavelength and its dose, not whether it says laser on the box. Each source has practical strengths. A laser can put a measured dose into a small, exact spot and holds its wavelength tightly. LEDs cover a face or a back in one session, cost far less, and suit home use.
What has each been tested for?
Lasers have mostly been tested for pain in joints, tendons and the neck. LEDs have mostly been tested on skin.
| Study | Source | What it found |
|---|---|---|
| Chow 2009, Lancet, 16 trials, 820 people with neck pain | Low-level lasers | Pain fell by about 20 mm on a 100 mm scale, with benefit lasting up to 22 weeks in chronic neck pain |
| Stausholm 2019, BMJ Open, 22 placebo-controlled trials, 1,063 people with knee osteoarthritis | Low-level lasers | Pain at the end of treatment was 14 mm lower than placebo on a 100 mm scale, and 19 mm lower in the trials that used recommended doses |
| Lee 2007, 76 people, split-face, sham-controlled | 633 and 830 nm LEDs | Fewer wrinkles and more elastic skin after eight sessions in four weeks, with more collagen seen under the microscope |
| Jagdeo 2018, review of 31 randomised LED trials in dermatology | LEDs | The best-supported uses were acne, cold sores and shingles, and the healing of fresh wounds |
Sources: Chow, Stausholm, Lee, Jagdeo. Reviews do not all agree on how large the pain effect is, and the results depend on dose. The practical point is that the two bodies of evidence do not transfer automatically: a laser trial on knees says little about an LED mask, and a skin trial with LEDs says little about a clinic laser. Red light therapy for pain and inflammation and red light therapy for the neck go through the pain trials.
How does a clinic cold laser compare with a home device?
A clinic laser treats one small spot at a time under a clinician's control. A home device lights a larger area at lower precision, on your own schedule.
| Clinic cold laser | Home LED panel | Home face mask | |
|---|---|---|---|
| Who operates it | Physiotherapist, chiropractor, vet or other clinician | You | You |
| Area | One spot at a time | A large area of the body | The face |
| Time | 20 to 300 seconds per point | 10 to 15 minutes per area | 10 to 15 minutes |
| Course | 8 to 30 visits | Ongoing, several times a week | Ongoing, several times a week |
| Cost | Per visit | One purchase | One purchase |
| Eye protection | Goggles for patient and operator | Goggles | Depends on the design; follow the manual |
| Main evidence | Pain in joints, tendons and the neck | Skin and recovery trials with LEDs | Skin trials, mostly with LED masks |
How much does cold laser therapy cost, and how many sessions?
WebMD gives a figure of up to $200 a session and a course of between 8 and 30 treatments. Health insurance often does not cover it.
Sessions are short, with the light on each spot for 30 to 60 seconds, and are usually booked two to four times a week. WebMD, Spine-health. Vets use the same treatment on dogs; the American Kennel Club puts it at $30 to $70 a session, with at least six sessions. AKC. Red light therapy for dogs covers pets, and how much red light therapy costs compares clinics, studios and home devices.
What do the laser classes mean?
The class tells you how hazardous the beam is to the eyes and skin. The higher the class, the more powerful the laser.
| Class | Power | Hazard | Everyday example |
|---|---|---|---|
| 1 | Very low | Considered non-hazardous | Laser printers, disc players |
| 2 | Up to 1 mW, visible | Hazardous only if stared at | Barcode scanners |
| 3R (IIIa) | 1 to 5 mW | Can be hazardous for a moment if viewed directly | Laser pointers |
| 3B (IIIb) | 5 to 500 mW | An immediate eye hazard if viewed directly | Most cold lasers in clinics |
| 4 (IV) | Above 500 mW | A hazard to eyes and skin, from the direct or reflected beam | High-power therapy lasers |
Sources: FDA, OSHA. This is why clinics and vets hand out goggles: therapy lasers are Class 3B or 4, and much of their light is invisible near-infrared, which gives the eye no warning. A "Class IV laser" in an advertisement means a laser above half a watt. Veterinary sources describe the higher class as faster, needing a few minutes where a lower-power laser might need twenty, not as more effective. VCA.
LED devices are assessed under a separate lamp-safety standard. On any device, read the label and the manual for its eye instructions, and follow them. Do you need goggles for red light therapy covers eye protection at home.
Can you do cold laser therapy at home?
Home devices deliver the same kind of light, mostly from LEDs and in a few cases from small laser diodes. They are not the same as a clinician placing a measured dose on a chosen point.
What a home device offers is regular use without appointments, over a larger area. What it does not offer is the clinician's choice of point and dose, which is how the pain trials were run. If you are being treated for an injury or a painful joint, a home device is something to raise with the person treating you, not a replacement for them.
Which should you choose?
Match the tool to the job and to the evidence.
- A sore tendon, joint or neck, and you want what the trials used: a clinician with a therapy laser.
- Skin on the face: the trials used LED panels and masks, at home or in a clinic. Do red light masks work has the numbers.
- Large areas at home, several times a week: an LED panel.
- Either way: check the wavelengths in nanometres, the output, the timer and the eye instructions before the word laser.
Kivorla: one device with laser diodes, one with LEDs
Our mask uses laser diodes and our panel uses LEDs. We do not claim that either source gives better results than the other.
The 4-Wavelength Red Light Therapy Mask produces its red and near-infrared light with VCSEL laser diodes: 72 at 665 nm, 72 at 850 nm and 20 at 1064 nm. A VCSEL, or vertical-cavity surface-emitting laser, is a small laser that emits from the surface of its chip; the same family of component is used in the face-recognition sensors of phones and in computer mice. RP Photonics. What they bring is an engineering property: a laser diode holds its wavelength tightly, within 3 nm of the stated figure on our mask, and 1064 nm is hard to produce efficiently with an LED. Deep near-infrared at 1064 nm explains that wavelength. The mask is not a clinic cold laser. Its diodes are spread across the face instead of aimed at one point, it has an opening at the eyes with no diodes over them, and its precautions say not to stare directly at the light source.
The 9-Spectrum Red Light Therapy Panel uses LEDs at nine wavelengths from 480 to 1060 nm, each dimmable, and comes with goggles. Neither device has been through its own clinical trial.
Read the precautions before ordering, since returns are accepted within 30 days, less a 10% restocking fee if the device is unopened with its seals intact, or 20% if it is opened but undamaged and complete. Standard shipping to the US, UK and Germany is free.
Kivorla devices are general wellness devices, not medical devices, and are not a substitute for treatment from a clinician. If you have pain or an injury, speak to your doctor or physiotherapist.