In plain terms, cold laser therapy is low-level laser therapy (LLLT), also called photobiomodulation (PBM). The “cold” in the name means the light is not intense enough to produce meaningful tissue heat, so nothing gets burned. It is a treatment category, not one standardized device or drug, and it is sometimes marketed as “red light therapy” even though that label can be misleading.
Other names you will see include low-power laser therapy and soft laser biostimulation. Clinical summaries most often describe wavelengths in the 600–1000 nm range, and a typical session simply places the probe on the skin or moves it over the treatment area.
How Cold Laser Therapy Works
Cold laser therapy works by delivering low-energy photons into tissue. Those photons are absorbed by natural photoreceptors and chromophores in cells, and that absorption triggers biochemical signaling changes associated with less pain, less inflammation, and sometimes improved tissue repair.
Because protocols vary by condition and device, there is no universal dose or session length. The right wavelength, power, and treatment plan come from the device’s cleared labeling or the clinician’s protocol, and most plans use a series of sessions rather than one visit.
Cold lasers are non-ablative and non-cauterizing. They do not cut, vaporize, or seal tissue, so they should not be confused with surgical lasers.
What Is Cold Laser Therapy Used For?
Cold laser therapy is used mainly for pain relief and inflammation, with additional applications in wound healing, hair loss, and oral mucositis. The common uses below come with realistic caveats because the evidence is not uniform across conditions.
| Common Use | What It’s Used For | Honest Caveat |
|---|---|---|
| Musculoskeletal and back pain | Joint, muscle, and low-back discomfort | Often used as adjunct therapy; results vary by condition and dose |
| Tendon disorders and trigger points | Tendonitis and localized muscle knots | May be part of physical therapy, not a proven stand-alone fix |
| Osteoarthritis | Knee and joint pain or stiffness | Some trials show relief; response depends on device and dose |
| Carpal tunnel syndrome | Mild to moderate hand and wrist pain | Evidence is supportive but not uniformly strong |
| Wound healing | Ulcers, burns, diabetic and post-surgical wounds | Evidence is mixed; standard wound care still comes first |
| Androgenetic alopecia | Pattern hair loss in men and women | FDA-cleared LLLT for this use; regrowth is modest and slow |
| Oral mucositis | Mouth sores from cancer treatment | MASCC guidelines support its use for prevention |
For any use, the practical question is not whether cold laser therapy works as a general idea. The real question is whether the specific device is FDA-cleared for your condition and dosed correctly. A PubMed review of low-level laser therapy describes many of these uses as adjunctive or complementary care, meaning they work with conventional treatment rather than instead of it.
Safety, Evidence, And Limits
- FDA clearance is device-specific. The NIH Bookshelf review of low-level laser therapy notes that the Erchonia FX 635, which emits 635 nm light, was the first LLLT device cleared by the FDA for lower back pain. The first cold laser clearance came in 2001. Neither fact means the entire category is cleared for the same claims.
- Class III and Class IV lasers are not cold lasers. Higher-power therapeutic lasers can heat or damage tissue if misused, so check the power, wavelength, and cleared indication of any device you consider.
- The evidence is mixed by condition. Some applications have strong support, while others are still viewed as adjunctive or complementary rather than definitive standalone treatment.
Also check whether the device is actually a laser. Some consumer products labeled “cold laser” use LEDs instead, and that distinction matters because FDA clearance, output power, and light delivery are not equivalent.
If you are comparing at-home units, our tested roundup of the best cold laser devices is a practical place to start.
FAQs
Does cold laser therapy hurt?
Is cold laser therapy the same as red light therapy?
Not exactly. The terms overlap in marketing, but cold laser therapy, LLLT, and PBM are not automatically interchangeable with every red light LED device. Wavelengths, power output, and FDA clearance differ, so check what a specific device is cleared to treat before assuming the results will be the same.
Does cold laser therapy actually work?
It depends on the condition. Evidence supports FDA-cleared uses such as lower back pain and pattern hair loss, but the research is mixed for other applications. Many clinical summaries describe cold laser as adjunctive care, meaning it works alongside physical therapy, medication, or standard wound care rather than replacing them.
References & Sources
- Aetna. “Clinical Policy Bulletin: Low-Level Laser Therapy.” Describes milliwatt range and minimal temperature rise for cold laser devices.
- NCBI Bookshelf. “Low-Level Laser Therapy (LLLT).” Overview of mechanisms, uses, and FDA-cleared device examples, including the Erchonia FX 635.
- PubMed. “Low-Level Laser (Light) Therapy.” Review covering evidence and applications of low-level laser therapy.