Cold Laser Therapy (LLLT): Uses, Benefits, and What the Research Shows

Cold laser therapy, also called low-level laser therapy (LLLT) or photobiomodulation (PBM), uses red and near-infrared light between about 630 and 980 nm to ease pain, calm inflammation and support tissue repair without heating or cutting tissue. The best evidence covers neck pain, knee osteoarthritis, tendinopathy, oral mucositis and pattern hair loss: a 2009 meta-analysis in The Lancet pooled 16 randomized trials with 820 patients and found LLLT reduced neck pain for up to 22 weeks compared with placebo [7].

You have probably seen cold laser therapy mentioned alongside other regenerative treatments at physical therapy clinics, sports medicine offices, and integrative health practices. It has been around for decades, used everywhere from NASA research labs to professional sports training rooms. Separating the real science from the marketing hype can be tricky.

So what does cold laser therapy actually do? Which conditions does it help? And what does the published research say?

The sections below move from the cellular mechanism to the clinical evidence, the cost and regulatory picture, and what a course of treatment looks like, so you can make an informed decision about whether this therapy belongs in your recovery plan. When you are ready to compare providers, the directory of cold laser therapy clinics lists practices by city and state.

What Is Cold Laser Therapy?

Cold laser therapy, formally known as low-level laser therapy (LLLT) or photobiomodulation (PBM), uses specific wavelengths of light to stimulate healing and reduce pain and inflammation in damaged tissues [1]. The term “cold” distinguishes it from high-power surgical lasers that cut or ablate tissue. Cold lasers do not generate significant heat, and you typically feel nothing, or at most a mild warmth, during treatment.

The therapy uses light in the red (630 to 670 nm) and near-infrared (810 to 980 nm) wavelength ranges, delivered at low power densities. These wavelengths can penetrate skin and soft tissue to reach cells, where they trigger a chain of biological responses [2]. Red light is absorbed closer to the surface, while near-infrared light reaches deeper into muscle, tendon and joint tissue.

The first clinical applications of low-level laser therapy date back to 1967, when Hungarian physician Endre Mester observed that low-power laser light accelerated hair growth and wound healing in mice. Since then, thousands of studies have investigated its effects on pain, inflammation, tissue repair, and neurological conditions [3].

Other names for cold laser therapy

Clinics and studies use several names for the same family of treatments. You will see low-level laser therapy (LLLT), low-level light therapy, low-intensity laser therapy, soft laser, therapeutic laser, Class 3B or Class 4 laser therapy, and photobiomodulation therapy (PBMT). Photobiomodulation is now the preferred scientific term because it also covers light-emitting diode (LED) devices that deliver similar wavelengths without a laser. Our low-level laser therapy treatment guide collects these terms and the conditions each is used for.

Who provides cold laser therapy?

Cold laser therapy is delivered by physical therapists, chiropractors, sports medicine physicians, physiatrists (physical medicine and rehabilitation doctors), podiatrists, dentists, dermatologists, oncology supportive care teams and some acupuncturists, who sometimes call it laser acupuncture. The provider's training in dosing matters more than the title on the door, because the same device can be used well or poorly.

How Cold Laser Therapy Works: The Mechanism of Action

Understanding how photobiomodulation works at the cellular level helps explain both its benefits and its limitations.

The Mitochondrial Connection

The primary target of cold laser light is cytochrome c oxidase (CCO), an enzyme within the mitochondrial electron transport chain. When photons of the right wavelength are absorbed by CCO, several things happen [4]:

• Increased ATP production. The enzyme becomes more efficient, boosting the cell’s energy output. Cells with more ATP can repair themselves faster, reduce inflammation, and carry out normal functions more effectively.
• Release of nitric oxide. Nitric oxide bound to CCO is displaced by the photons, freeing it to act as a vasodilator and signaling molecule. This improves local blood flow and triggers downstream healing cascades [5].
• Reactive oxygen species (ROS) signaling. A brief, controlled increase in ROS activates transcription factors like NF-kB, which upregulate the expression of genes involved in cell survival, proliferation, and tissue repair [4].
• Reduced oxidative stress. Paradoxically, while a brief ROS burst initiates healing, the overall effect of PBM is a net reduction in oxidative stress and inflammatory markers over time [6].

The Biphasic Dose Response

One of the most important concepts in cold laser therapy is the Arndt-Schulz principle, or biphasic dose response. Too little light has no effect. The right dose stimulates healing. Too much light can actually inhibit cellular function [2].

This is why proper dosing, including wavelength, power density, treatment time, and total energy delivered, matters so much. A poorly calibrated device or incorrect treatment protocol can produce underwhelming results, which partly explains the inconsistent outcomes seen in some older studies.

Dosing terms you may hear

Practitioners describe a dose with a few standard attributes. Knowing them makes it easier to ask useful questions during a consultation.

Conditions Treated with Cold Laser Therapy

Research has investigated cold laser therapy for a wide range of conditions. The areas with the strongest evidence are musculoskeletal pain, tendon problems, oral mucositis and pattern hair loss, while uses such as neuropathy and nerve injury rest on smaller studies.

Musculoskeletal Pain

Pain relief is the most common clinical application of cold laser therapy, and the evidence here is substantial. Clinics most often use it for chronic pain in the neck, back, knees and shoulders.

A 2009 systematic review in The Lancet by Chow and colleagues analyzed 16 randomized controlled trials involving 820 patients with chronic neck pain. LLLT significantly reduced pain immediately after treatment and up to 22 weeks later compared to placebo [7].

For osteoarthritis, a 2019 meta-analysis in BMJ Open by Stausholm and colleagues found that PBM significantly reduced pain and improved function in knee osteoarthritis, with effects that were sustained over follow-up periods of 4 to 12 weeks [8]. The benefit was clearest in trials that used doses within WALT recommendations.

Low back pain has also been studied. A 2015 meta-analysis in Arthritis Research & Therapy by Huang and colleagues reported that LLLT provided short-term pain relief in patients with nonspecific chronic low back pain, though the authors noted the need for more standardized protocols [9]. An earlier Cochrane review by Yousefi-Nooraie and colleagues (2008) found too little data to draw firm conclusions for low back pain, which shows how much the picture depends on study quality and dosing [17].

Tendinopathies

Tennis elbow (lateral epicondylitis), Achilles tendinopathy, and other tendon disorders respond well to cold laser therapy when proper dosing parameters are used. A 2010 systematic review with meta-analysis by Tumilty and colleagues found that LLLT can be effective for tendinopathy when recommended doses are used, and that combining it with exercise is a common and reasonable approach [10]. Patients with tennis elbow often receive laser alongside eccentric loading exercises, bracing, or shockwave therapy.

Inflammation

Cold laser therapy has anti-inflammatory effects that operate through multiple pathways. It reduces pro-inflammatory cytokines (including TNF-alpha, IL-1 beta, and IL-6), decreases edema, and modulates immune cell activity [6]. This makes it useful not only for musculoskeletal inflammation but also for inflammatory conditions affecting other tissues, though most of the mechanistic data comes from laboratory and animal work.

Wound Healing and Tissue Repair

PBM accelerates wound healing by stimulating fibroblast proliferation, increasing collagen synthesis, and promoting angiogenesis (the formation of new blood vessels) [3]. Clinical applications include:

• Diabetic ulcers
• Post-surgical wound healing
• Burns
• Oral mucositis (a painful side effect of chemotherapy and radiation)

For oral mucositis specifically, the evidence is strong enough that clinical guidelines from organizations including the Multinational Association of Supportive Care in Cancer (MASCC) and the International Society of Oral Oncology (ISOO) recommend PBM for prevention in selected patient groups, such as people receiving stem cell transplant conditioning or head and neck radiotherapy [11]. For chronic wounds such as diabetic foot ulcers, trials are smaller and laser is used alongside standard wound care, not instead of it.

Hair Loss

Endre Mester’s original 1967 observation about laser-stimulated hair growth has been supported by modern research. Low-level laser devices are FDA cleared for androgenetic alopecia (pattern hair loss) in both men and women.

A 2014 randomized, double-blind, sham-controlled trial by Jimenez and colleagues, published in the American Journal of Clinical Dermatology, found that a laser comb significantly increased hair density compared to sham devices over a 26-week treatment period [16]. Lanzafame and colleagues (2013) reported similar gains in hair counts in men using a red light laser and LED device [12]. The mechanism appears to involve stimulation of hair follicle stem cells, increased blood flow to the scalp, and a shift of follicles from the telogen (resting) to anagen (growth) phase. Laser caps and combs are often compared with minoxidil, finasteride and PRP in hair loss treatment plans.

Neuropathy and Nerve Injuries

Emerging research suggests cold laser therapy may benefit peripheral neuropathy and nerve injuries. A 2012 study by Yamany and Sayed in the Journal of Advanced Research found that LLLT reduced pain and improved measures of neurovascular function in patients with diabetic peripheral neuropathy [13]. Animal studies have also demonstrated accelerated nerve regeneration after injury with appropriate laser parameters. The human evidence here is small and early, so neuropathy belongs in the promising rather than established column.

Temporomandibular Joint Disorders (TMJ)

Several systematic reviews support the use of LLLT for TMJ-related pain, with improvements in mouth opening capacity and reduction in pain scores [14]. Dentists and orofacial pain specialists use it for temporomandibular joint disorder alongside splints, jaw exercises and stress management.

Evidence at a glance

The table below summarizes how strong the published evidence is for each use discussed in this section, based on the reviews cited.

Cold Laser Therapy vs Red Light Therapy and Other Options

Cold laser therapy and red light therapy are both forms of photobiomodulation, and they share the same mitochondrial mechanism. The difference is the light source: cold lasers emit a narrow, focused, coherent beam aimed at a specific spot, while red light therapy usually uses LED panels that bathe a wider area in less concentrated light.

In practice, clinics use handheld lasers for a defined joint, tendon or trigger point, and LED panels or beds for skin, larger muscle groups, or general recovery. Our guide to red light therapy covers the LED side in more depth, and the red light therapy overview on the blog compares home and clinic devices.

Patients often combine laser with shockwave therapy clinics or physical therapy for stubborn tendon problems. Each option has its own evidence base, and none of them replaces a diagnosis.

What a Cold Laser Therapy Session Looks Like

A cold laser therapy session is short, painless and needs no recovery time. Here is what to expect from start to finish.

Before the Session

The practitioner will assess your condition, identify the treatment area, and select the appropriate device and protocol. No special preparation is needed on your part. You do not need to fast or avoid any activities beforehand.

Tell the practitioner about pregnancy, any history of cancer, seizure disorders, and medications that make you sensitive to light, because these affect where and whether the laser is used.

During Treatment

You will be positioned comfortably, usually sitting or lying down. The practitioner applies the laser device directly to the skin over the treatment area. Depending on the device, this might be a small handheld probe or a larger panel with multiple diodes.

A typical session lasts 5 to 20 minutes per treatment area. You will feel little to nothing during the treatment. There is no pain, no vibration, and usually no sensation at all. Some patients report a mild warmth, particularly with near-infrared wavelengths.

Eye protection is standard practice, as direct laser exposure to the eyes must be avoided.

After Treatment

There is no downtime. You can return to normal activities immediately. Some patients notice pain relief within the first session, while others require several treatments before noticing improvements. A typical treatment course consists of 8 to 12 sessions, often scheduled 2 to 3 times per week.

How many sessions does cold laser therapy take?

Most clinic protocols for pain and tendon problems run 8 to 12 sessions at 2 to 3 visits per week, so a full course usually spans about three to six weeks. Acute injuries may need fewer visits, while chronic conditions such as knee osteoarthritis sometimes continue with occasional maintenance sessions. Hair loss protocols are different: the home devices studied in trials were used several times a week for about six months before results were measured [16].

At-Home Devices

Consumer-grade cold laser and LED devices are available for home use. These range from handheld laser devices to wearable LED pads and helmet-style devices for hair loss. While some of these products are FDA cleared and backed by research, many are underpowered or use wavelengths that are not well supported by evidence.

If you are considering a home device, look for one that specifies its wavelength (ideally 630 to 670 nm or 810 to 980 nm), power output, and energy density. Consulting with a knowledgeable practitioner before purchasing can save you from wasting money on an ineffective device.

Is Cold Laser Therapy FDA Approved? Cost and Insurance

Cold laser devices are FDA cleared, not FDA approved, for a limited set of uses. The FDA regulates them as medical devices, and most reach the market through the 510(k) pathway by showing they are substantially equivalent to a device already on the market. Cleared indications include pattern hair loss and the temporary relief of minor muscle and joint pain, stiffness and muscle spasm.

Clearance means the FDA accepted that a device is comparable to an existing one. It does not mean the agency reviewed proof that it works for every condition a clinic may offer it for. Uses such as neuropathy, wound healing outside of trials, or brain conditions are off label.

How much does cold laser therapy cost?

Cold laser therapy is usually a cash pay service, and the price per session varies by region, provider type, device class and whether laser is bundled with physical therapy or chiropractic care. Ask each clinic for the per session fee, the number of sessions in the proposed course, and whether package pricing is refundable if you stop early. The national LLLT clinic list lets you compare providers in your state before you call.

Does insurance cover cold laser therapy?

Most private insurers classify low-level laser therapy for pain as investigational or not medically necessary, so coverage is uncommon. When laser is part of a broader physical therapy plan, the other parts of the visit may be billed to insurance while the laser portion is not. Photobiomodulation for oral mucositis is sometimes provided within cancer centers as part of supportive care. Check your plan's medical policy before starting a course.

Safety and Side Effects

Cold laser therapy has a strong safety record in clinical studies. The most common “side effect” is simply no response, usually due to inadequate dosing.

Serious adverse events are rare. A 2015 review by Cotler, Chow, Hamblin and Carroll found that LLLT is well tolerated across a wide range of musculoskeletal conditions and patient populations [15]. There are a few precautions to know:

• Pregnancy. Cold laser therapy is generally avoided over the abdomen during pregnancy, though there is no direct evidence of harm.
• Cancer. Direct application over known tumors is typically avoided due to theoretical concerns about stimulating cell proliferation, though research in this area is evolving.
• Photosensitivity. Patients taking photosensitizing medications should discuss this with their practitioner.
• Eyes. Direct laser exposure to the eyes must always be avoided. Protective eyewear is standard.
• Epilepsy. Transcranial PBM should be used with caution in patients with seizure disorders.

There are no known drug interactions, and cold laser therapy can usually be combined with most other treatments, including physical therapy, chiropractic care, and medications. Higher-output Class 4 lasers carry a small risk of skin warming or burns if used incorrectly, which is one more reason to ask what device a clinic uses.

What the Critics Say

Despite a large body of supportive research, cold laser therapy still faces skepticism in some quarters. The main criticisms include:

Inconsistent study results. Early LLLT studies used widely varying parameters, making it difficult to compare outcomes across trials. Many negative studies used suboptimal doses or inappropriate wavelengths [2]. More recent research using standardized parameters has produced more consistent results.

Placebo effect. As with any therapy, some benefit may be attributable to placebo. Multiple sham-controlled trials have demonstrated statistically significant effects beyond placebo, particularly for pain and inflammation [7] [8].

Mechanism complexity. The biphasic dose response means that getting the parameters right is essential. This complexity means that not every practitioner achieves optimal results, even with a sound therapeutic modality.

Gaps in the evidence. Many trials are small, follow patients for weeks rather than years, and come from a limited number of research groups. The 2008 Cochrane review on low back pain is a reminder that some uses still lack firm conclusions [17]. Long-term benefit beyond a few months is not well established for most conditions.

How to Get the Most from Cold Laser Therapy

If you decide to pursue cold laser therapy, keep these points in mind:

• Choose a qualified practitioner. Look for providers who understand photobiomodulation dosing principles and use professional-grade equipment with documented wavelengths and power outputs.
• Ask about the protocol. A good practitioner should be able to tell you the wavelength, power density, energy density, and treatment time being used, and explain why those parameters were chosen for your condition.
• Be consistent. Like most regenerative therapies, cold laser therapy works best with consistent, repeated treatments. Skipping sessions reduces cumulative benefit.
• Combine with other therapies. Cold laser works especially well as part of a multimodal approach. Pairing it with exercise, manual therapy, or nutritional support can add to the benefit, and exercise is the usual partner in tendon studies [10].
• Set realistic expectations. Cold laser therapy is not a quick fix. It is a well-studied tool that can meaningfully reduce pain, support healing, and reduce inflammation when used correctly.

Questions to ask a cold laser therapy clinic

1. What wavelength and laser class will you use, and why for my condition?
2. How many sessions do you expect, and when will we check whether it is working?
3. What will each session cost, and is any part billed to insurance?
4. Who delivers the treatment, and what training do they have in photobiomodulation dosing?
5. What else is in the plan, such as exercise, manual therapy or bracing?

When you browse clinics offering low-level laser therapy on Regenerated.com, listing order is not paid ranking, Featured slots are labeled and capped, and Verified means the clinic completed credential checks, not that it paid. Regenerated.com is free for patients, and inclusion in the directory is not an endorsement. The guide to Featured, Verified and organic listings explains each label.

When to See a Doctor

Cold laser therapy is appropriate for many musculoskeletal and inflammatory conditions, but it is not a substitute for a proper medical evaluation. See a physician if you experience:

• Sudden, severe, or unexplained pain
• Signs of infection (redness, warmth, swelling, fever)
• Symptoms of nerve damage such as numbness, weakness, or loss of bowel or bladder control
• Pain that worsens despite treatment
• Any new or unexplained symptoms

If you have a diagnosed condition and are considering adding cold laser therapy to your treatment plan, discuss it with your primary care provider or specialist. Most physicians are open to complementary therapies that have a reasonable evidence base and good safety profile.

Frequently asked questions about cold laser therapy

Does cold laser therapy really work?

Cold laser therapy works for some conditions when the dose is right. Meta-analyses support short and medium-term pain relief for chronic neck pain, knee osteoarthritis and tendinopathy, and MASCC/ISOO guidelines recommend it to prevent oral mucositis in selected cancer patients. Evidence for low back pain is mixed, and uses such as neuropathy rest on small studies. Results depend heavily on wavelength, energy delivered and the number of sessions, which is why outcomes vary between clinics and between trials.

How many sessions of cold laser therapy do you need?

Most clinic courses for pain or tendon problems run 8 to 12 sessions, scheduled 2 to 3 times per week over roughly three to six weeks. Some people notice relief after the first visit, while others need several sessions before any change. Chronic conditions may need occasional maintenance visits afterward. Hair loss is the exception, since the devices studied in trials were used at home several times a week for about six months before results were measured.

Is cold laser therapy covered by insurance?

Cold laser therapy is usually not covered by insurance. Most private insurers classify low-level laser therapy for pain as investigational or not medically necessary, so patients typically pay out of pocket. When laser is delivered inside a physical therapy or chiropractic visit, other parts of that visit may still be billed to insurance. Ask the clinic for the per session fee and total course cost in writing, and check your plan's medical policy before you start.

Is cold laser therapy the same as red light therapy?

Cold laser therapy and red light therapy are related but not the same. Both are forms of photobiomodulation that use red and near-infrared light to act on mitochondria. Cold lasers deliver a focused, coherent beam to a small target such as a tendon or joint, while red light therapy usually uses LED panels that cover a wider area with less concentrated light. Clinics tend to choose lasers for specific injuries and LED panels for skin, hair or larger areas.

What are the side effects of cold laser therapy?

Side effects of cold laser therapy are uncommon and usually mild, such as brief warmth, tingling or temporary soreness in the treated area. The main safety rule is eye protection, because direct laser exposure can damage the eyes. Practitioners avoid treating over the abdomen in pregnancy, over known tumors, and they take extra care with photosensitizing medications and seizure disorders. Higher-power Class 4 lasers can warm or burn skin if used incorrectly.

Is cold laser therapy FDA approved?

Cold laser devices are FDA cleared rather than FDA approved. Most reach the market through the 510(k) pathway, which means the FDA accepted that a device is substantially equivalent to one already sold. Cleared uses include pattern hair loss and temporary relief of minor muscle and joint pain and stiffness. Clinics may also offer laser for other conditions, such as neuropathy, which are off label and supported by less evidence. Ask what a specific device is cleared for.

Sources

1. Chung, H., Dai, T., Sharma, S. K., Huang, Y. Y., Carroll, J. D., & Hamblin, M. R. (2012). The nuts and bolts of low-level laser (light) therapy. Annals of Biomedical Engineering, 40(2), 516-533. PMID: 22045511 ↩
2. Huang, Y. Y., Chen, A. C., Carroll, J. D., & Hamblin, M. R. (2009). Biphasic dose response in low level light therapy. Dose-Response, 7(4), 358-383. PMID: 20011653 ↩
3. de Freitas, L. F., & Hamblin, M. R. (2016). Proposed mechanisms of photobiomodulation or low-level light therapy. IEEE Journal of Selected Topics in Quantum Electronics, 22(3), 7000417. PMID: 28070154 ↩
4. Karu, T. I. (2008). Mitochondrial signaling in mammalian cells activated by red and near-IR radiation. Photochemistry and Photobiology, 84(5), 1091-1099. PMID: 18651871 ↩
5. Hamblin, M. R. (2018). Mechanisms and mitochondrial redox signaling in photobiomodulation. Photochemistry and Photobiology, 94(2), 199-212. PMID: 29164625 ↩
6. Hamblin, M. R. (2017). Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophysics, 4(3), 337-361. PMID: 28748217 ↩
7. Chow, R. T., Johnson, M. I., Lopes-Martins, R. A., & Bjordal, J. M. (2009). Efficacy of low-level laser therapy in the management of neck pain: A systematic review and meta-analysis of randomised placebo or active-treatment controlled trials. The Lancet, 374(9705), 1897-1908. PMID: 19913903 ↩
8. Stausholm, M. B., Naterstad, I. F., Joensen, J., Lopes-Martins, R. A. B., Saebø, H., Lund, H., et al., & Bjordal, J. M. (2019). Efficacy of low-level laser therapy on pain and disability in knee osteoarthritis: Systematic review and meta-analysis of randomised placebo-controlled trials. BMJ Open, 9(10), e031142. PMID: 31662383 ↩
9. Huang, Z., Ma, J., Chen, J., Shen, B., Pei, F., & Kraus, V. B. (2015). The effectiveness of low-level laser therapy for nonspecific chronic low back pain: A systematic review and meta-analysis. Arthritis Research & Therapy, 17(1), 360. PMID: 26667480 ↩
10. Tumilty, S., Munn, J., McDonough, S., Hurley, D. A., Basford, J. R., & Baxter, G. D. (2010). Low level laser treatment of tendinopathy: A systematic review with meta-analysis. Photomedicine and Laser Surgery, 28(1), 3-16. PMID: 19708800 ↩
11. Zadik, Y., Arany, P. R., Fregnani, E. R., Bossi, P., Antunes, H. S., Bensadoun, R. J., et al., & Lalla, R. V. (2019). Systematic review of photobiomodulation for the management of oral mucositis in cancer patients and clinical practice guidelines. Supportive Care in Cancer, 27(10), 3969-3983. PMID: 31286228 ↩
12. Lanzafame, R. J., Blanche, R. R., Bodian, A. B., Chiacchierini, R. P., Fernandez-Obregon, A., & Kazmirek, E. R. (2013). The growth of human scalp hair mediated by visible red light laser and LED sources in males. Lasers in Surgery and Medicine, 45(8), 487-495. PMID: 24078483 ↩
13. Yamany, A. A., & Sayed, H. M. (2012). Effect of low level laser therapy on neurovascular function of diabetic peripheral neuropathy. Journal of Advanced Research, 3(1), 21-28. ↩
14. Maia, M. L., Bonjardim, L. R., Quintans Jde, S., Ribeiro, M. A., Maia, L. G., & Conti, P. C. (2012). Effect of low-level laser therapy on pain levels in patients with temporomandibular disorders: A systematic review. Journal of Applied Oral Science, 20(6), 594-602. PMID: 23329239 ↩
15. Cotler, H. B., Chow, R. T., Hamblin, M. R., & Carroll, J. (2015). The use of low level laser therapy (LLLT) for musculoskeletal pain. MOJ Orthopedics & Rheumatology, 2(5), 00068. PMID: 26858986 ↩
16. Jimenez, J. J., Wikramanayake, T. C., Bergfeld, W., Hordinsky, M., Hickman, J. G., Hamblin, M. R., et al. (2014). Efficacy and safety of a low-level laser device in the treatment of male and female pattern hair loss: A multicenter, randomized, sham device-controlled, double-blind study. American Journal of Clinical Dermatology, 15(2), 115-127. PMID: 24474647 ↩
17. Yousefi-Nooraie, R., Schonstein, E., Heidari, K., & Rashidian, A. (2008). Low level laser therapy for nonspecific low-back pain. Cochrane Database of Systematic Reviews, (2), CD005107. PMID: 18425909 ↩