Low-level laser therapy (LLLT) is a form of alternative medicine that applies low-level (low-power) lasers or light-emitting diodes (LEDs) to the surface of or in orifices of the body. Whereas high-power lasers are used in laser medicineto cut or destroy tissue, it is claimed that application of low-power lasers relieves pain or stimulates and enhances cell function.
Despite a lack of consensus over its validity, some studies suggest that LLLT may be modestly effective, in relieving short-term pain for rheumatoid arthritis, osteoarthritis, acute and chronic neck pain, tendinopathy, and possibly, chronic joint disorders. The evidence for LLLT being useful in the treatment of low back pain, dentistry, and wound healing is unclear.
Variations of LLLT have gone by a variety of alternate names including low-power laser therapy (LPLT), soft laser therapy, low-intensity laser therapy, low-energy laser therapy, cold laser therapy, bio-stimulation laser therapy, photobiomodulation, photo-biotherapy, therapeutic laser, and monochromatic infrared light energy (MIRE) therapy. When LLLT is administered to so-called “acupuncture points“, the procedure may be called laser acupuncture. When applied to the head, LLLT may be known as transcranial photobiomodulation, transcranial near-infrared laser therapy (NILT) , or transcranial low level light therapy.
Various LLLT devices have been promoted for use in treatment of several musculoskeletal conditions including carpal tunnel syndrome (CTS), fibromyalgia, osteoarthritis, and rheumatoid arthritis. They have also been promoted for temporomandibular joint (TMJ) disorders, wound healing, smoking cessation, and tuberculosis. While these treatments may briefly help some people with pain management, evidence does not support claims that they change long term outcomes, or that they work better than other, low tech ways of applying heat.
Research is ongoing about the mechanism of LLLT. The effects of LLLT appear to be limited to a specified set of wavelengths of laser, and administering LLLT below the dose range does not appear to be effective. Photochemical reactions are well known in biological research; it may be that the light applied in low level laser therapy might react with the respiratory enzyme cytochrome c oxidase which is involved in the electron transport chain in mitochondria.
Hungarian physician and surgeon Endre Mester (1903-1984) is credited with the discovery of the biological effects of low power lasers, which occurred a few years after the 1960 invention of the ruby laser and the 1961 invention of the helium–neon (HeNe) laser. Mester accidentally discovered that low-level ruby laser light could regrow hair during an attempt to replicate an experiment that showed that such lasers could reduce tumors in mice. The laser he was using was faulty and wasn’t so powerful as he thought. It failed to affect the tumors, but he noticed that in the places where he had shaved the mice in order to do the experiments, the hair grew back more quickly on the treated mice than on those among the control group. He published those results in 1967. He went on to show that low level HeNe light could accelerate wound healing in mice. By the 1970s he was applying low level laser light to treat people with skin ulcers. In 1974 he founded the Laser Research Center at the Semmelweis Medical University in Budapest, and continued working there for the remainder of his life. His sons carried on his work and brought it to the United States.
By 1987 companies selling lasers were claiming that they could treat pain, accelerate healing of sports injuries, and treat arthritis, but there was little evidence for this at that time. By 2016 they had been marketed for wound healing, smoking cessation, tuberculosis, and musculoskeletal conditions such as temporomandibular joint disorders, carpal tunnel syndrome, fibromyalgia, osteoarthritis, and rheumatoid arthritis, and there was still little evidence for these uses, other than a possible use in temporarily treating muscle or joint pain. Mester originally called this approach “laser biostimulation'”, but it soon became known as “low level laser therapy” and with the adaptation of light emitting diodes by those studying this approach, it became known as “low level light therapy”, and to resolve confusion around the exact meaning of “low level”, the term “photobiomodulation” arose.
In the US as of 2006 the Centers for Medicare and Medicaid Services did not provide coverage for LLLT, as of 2014 Aetna did not provide coverage, and as of 2016 Cigna did not provide coverage.
A 2008 Cochrane Library review concluded that LLLT has insufficient evidence for treatment of nonspecific low back pain, a finding echoed in a 2010 review of chronic low back pain. A 2015 review found benefit in nonspecific chronic low-back pain.
LLLT may be useful in the treatment of both acute and chronic neck pain. In 2013, however, a systematic review and meta-analysis of LLLT for neck pain indicated that the benefit was not of significant importance and that the evidence had a high risk of bias.
There are tentative data that LLLT is useful in the short-term treatment of pain caused by rheumatoid arthritis, and possibly chronic joint disorders. While it does not appear to improve pain in temporomandibular disorders, it may improve function. Evidence for usefulness in osteoarthritis is poor.
There is tentative evidence of benefit in tendinopathy. A 2014 review found benefit in shoulder tendinopathy. A 2014 Cochrane review found tentative evidence that it may help in frozen shoulders.
Similarly, the use of lasers to treat chronic periodontitis and to speed healing of infections around dental implants is suggested, but there is insufficient evidence to indicate a use superior to traditional practices. There is tentative evidence for dentin hypersensitivity. It does not appear to be useful for orthodontic pain LLLT might be useful for wisdom tooth extraction (complications) and oral mucositis.
LLLT has been studied as a treatment for hair loss; a review in 2012 found little evidence to support the use of lasers to treat hair loss. A 2014 review found tentative evidence for benefit for lasers, while another 2014 review concluded that the results were mixed, had a high risk of bias, and that its effectiveness was unclear. A 2015 review found tentative evidence of benefit.
LLLT has been studied for traumatic brain injury (TBI) and stroke among other conditions. When applied to the head it is known as transcranial photobiomodulation or transcranial low level light therapy.
LLLT has been studied as a way to reduce pain and swelling in breast-cancer related lymphedema. Stephen Barrett, writing for Quackwatch, concluded in 2009 there was evidence to support LLLT use for temporary pain relief, but “there’s no reason to believe that they will influence the course of any ailment or are more effective than other forms of heat delivery.” Barrett’s position was unchanged as of 2017.
Veterinary clinics use cold laser devices to treat a wide variety of ailments, from arthritis to wounds, on dogs and cats. Very little research has been done on the effects of this treatment on animals. Currently, laser therapy equipment is aggressively marketed to veterinarians as a supposedly powerful therapeutic tool and revenue generator. Brennen McKenzie, president of the Evidence-Based Veterinary Medicine Association, has stated that “research into cold laser in dogs and cats is sparse and generally low quality. Most studies are small and have minimal or uncertain controls for bias and error”. While allowing that some studies show promising results, he reports that others do not. While believing that there is enough evidence to warrant further study, he concludes that there is not enough evidence to support routine clinical use of cold laser in animals.
- Bjordal, J. M.; Lopes-Martins, R. A.; Joensen, J. .; Couppe, C. .; Ljunggren, A. E.; Stergioulas, A. .; Johnson, M. I. (2008). “A systematic review with procedural assessments and meta-analysis of Low Level Laser Therapy in lateral elbow tendinopathy (tennis elbow)”. BMC Musculoskeletal Disorders. 9: 75. doi:10.1186/1471-2474-9-75. PMC 2442599. PMID 18510742.
- Bjordal, JM; Couppé, C; Chow, RT; Tunér, J; Ljunggren, EA (2003). “A systematic review of low level laser therapy with location-specific doses for pain from chronic joint disorders”. The Australian Journal of Physiotherapy. 49 (2): 107–16. doi:10.1016/s0004-9514(14)60127-6. PMID 12775206.
- Brosseau, L.; Welch, V.; Wells, G. A.; de Bie, R.; Gam, A.; Harman, K.; Morin, M.; Shea, B.; Tugwell, P. (2005). “Low level laser therapy (Classes I, II and III) for treating rheumatoid arthritis”. Cochrane Database of Systematic Reviews (4): CD002049. doi:10.1002/14651858.CD002049.pub2. PMID 16235295.
- Jamtvedt, G.; Dahm, K. T.; Christie, A.; Moe, R. H.; Haavardsholm, E.; Holm, I.; Hagen, K. B. (2007). “Physical Therapy Interventions for Patients with Osteoarthritis of the Knee: an Overview of Systematic Reviews”. Physical Therapy. 88 (1): 123–136. doi:10.2522/ptj.20070043. PMID 17986496.
- Chow, R.; Johnson, M.; Lopes-Martins, R.; Bjordal, J. (Nov 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”. Lancet. 374 (9705): 1897–1908. doi:10.1016/S0140-6736(09)61522-1. PMID 19913903.
- 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. doi:10.1089/pho.2008.2470. PMID 19708800.
- Yousefi-Nooraie, R.; Schonstein, E.; Heidari, K.; Rashidian, A.; Pennick, V.; Akbari-Kamrani, M.; Irani, S.; Shakiba, B.; Mortaz Hejri, S.; Mortaz Hejri, S. O.; Jonaidi, A. (2008). Yousefi-Nooraie, Reza, ed. “Low level laser therapy for nonspecific low-back pain” (PDF). Cochrane Database of Systematic Reviews(2): CD005107. doi:10.1002/14651858.CD005107.pub4. PMID 18425909.
- Middelkoop, M.; Rubinstein, S. M.; Kuijpers, T.; Verhagen, A. P.; Ostelo, R.; Koes, B. W.; Van Tulder, M. W. (2010). “A systematic review on the effectiveness of physical and rehabilitation interventions for chronic non-specific low back pain”. European Spine Journal. 20 (1): 19–39. doi:10.1007/s00586-010-1518-3. PMC 3036018. PMID 20640863.
- Cobb, C. M. (2006). “Lasers in Periodontics: A Review of the Literature”. Journal of Periodontology. 77 (4): 545–564. doi:10.1902/jop.2006.050417. PMID 16584335.
- Sculean, A.; Schwarz, F.; Becker, J. (2005). “Anti-infective therapy with an Er:YAG laser: influence on peri-implant healing”. Expert Review of Medical Devices. 2 (3): 267–76. doi:10.1586/174344220.127.116.117. PMID 16288590.
- Da Silva, J. P.; Da Silva, M. A.; Almeida, A. P. F.; Junior, I. L.; Matos, A. P. (2010). “Laser Therapy in the Tissue Repair Process: A Literature Review”. Photomedicine and Laser Surgery. 28 (1): 17–21. doi:10.1089/pho.2008.2372. PMID 19764898.
- Chung, Hoon; Dai, Tianhong; Sharma, Sulbha K.; Huang, Ying-Ying; Carroll, James D.; Hamblin, Michael R. (2011). “The Nuts and Bolts of Low-level Laser (Light) Therapy”. Annals of Biomedical Engineering. 40 (2): 516–533. doi:10.1007/s10439-011-0454-7. ISSN 0090-6964. PMC 3288797. PMID 22045511.
- American Cancer Society. Cold Laser Therapy Page archived April 24, 2015
- Lapchak, PA (December 2010). “Taking a light approach to treating acute ischemic stroke patients: transcranial near-infrared laser therapy translational science”. Annals of Medicine. 42 (8): 576–86. doi:10.3109/07853890.2010.532811. PMC 3059546. PMID 21039081.
- Barrett, S (February 6, 2017). “A Skeptical Look at Low Level Laser Therapy”. Quackwatch. Archived from the original on March 11, 2018.
- Migliorati, C; Hewson, I; Lalla, RV; Antunes, HS; Estilo, CL; Hodgson, B; Lopes, NN; Schubert, MM; Bowen, J; Elad, S; Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology, (MASCC/ISOO). (January 2013). “Systematic review of laser and other light therapy for the management of oral mucositis in cancer patients”. Supportive Care in Cancer. 21 (1): 333–41. doi:10.1007/s00520-012-1605-6. PMID 23001179.
- Oberoi, S; Zamperlini-Netto, G; Beyene, J; Treister, NS; Sung, L (2014). “Effect of prophylactic low level laser therapy on oral mucositis: a systematic review and meta-analysis”. PLOS One. 9 (9): e107418. Bibcode:2014PLoSO…9j7418O. doi:10.1371/journal.pone.0107418. PMC 4157876. PMID 25198431.
- Prindeze, Nicholas J.; Moffatt, Lauren T.; Shupp, Jeffrey W. (2012-11-01). “Mechanisms of action for light therapy: a review of molecular interactions”. Experimental Biology and Medicine (Maywood, N.J.). 237 (11): 1241–1248. doi:10.1258/ebm.2012.012180. ISSN 1535-3699. PMID 23239434.
- Perera, Judith (19 March 1987). “The ‘healing laser’ comes into the limelight‘“. New Scientist.
- Hamblin, MR (1 October 2016). “Shining light on the head: Photobiomodulation for brain disorders”. BBA Clinical. 6: 113–124. doi:10.1016/j.bbacli.2016.09.002. PMC 5066074. PMID 27752476.
- “Celebrating the 100th birthday of Professor Endre Mester”. Laser World. Swedish Laser-Medical Society. April 18, 2004. Archived from the original on March 3, 2016.
- “Decision memo for infrared therapy devices” (CAG00291N). Center for Medicare & Medicaid Services, Oct 24, 2006.
- “Infrared therapy”. Aetna clinical policy bulletin 0604, reviewed Oct 23, 2014. Aetna has additional information in its “Clinical Policy Bulletin on Cold Laser and High-Power Laser Therapies”.
- “CIGNA medical coverage policy: Low-level laser therapy”. Revised, July 15, 2016.
- Blue Cross and Blue Shield of Kansas City (Blue KC). “Low-Level Laser Therapy” (PDF). Policy No. 2.01.56. Retrieved 2 February 2019. (Policy reviewed each June; if link is dead try replacing “06-18” with a more recent year.)
- Huang, ZeYu; Ma, Jun; Chen, Jing; Shen, Bin; Pei, FuXing; Kraus, Virginia Byers (2015-01-01). “The effectiveness of low-level laser therapy for nonspecific chronic low back pain: a systematic review and meta-analysis”. Arthritis Research & Therapy. 17: 360. doi:10.1186/s13075-015-0882-0. ISSN 1478-6362. PMC 4704537. PMID 26667480.
- Kadhim-Saleh, Amjed; Maganti, Harinad; Ghert, Michelle; Singh, Sheila; Farrokhyar, Forough (2013-10-01). “Is low-level laser therapy in relieving neck pain effective? Systematic review and meta-analysis”. Rheumatology International. 33(10): 2493–2501. doi:10.1007/s00296-013-2742-z. ISSN 1437-160X. PMID 23579335.
his systematic review provides inconclusive evidence because of significant between-study heterogeneity and potential risk of bias.
- Chen, J.; Huang, Z.; Ge, M.; Gao, M. (2015-04-01). “Efficacy of low-level laser therapy in the treatment of TMDs: a meta-analysis of 14 randomised controlled trials”. Journal of Oral Rehabilitation. 42 (4): 291–299. doi:10.1111/joor.12258. ISSN 1365-2842. PMID 25491183.
- Huang, Z.; Chen, J.; Ma, J.; Shen, B.; Pei, F.; Kraus, V. B. (2015-09-01). “Effectiveness of low-level laser therapy in patients with knee osteoarthritis: a systematic review and meta-analysis”. Osteoarthritis and Cartilage. 23 (9): 1437–1444. doi:10.1016/j.joca.2015.04.005. ISSN 1522-9653. PMC 4814167. PMID 25914044.
- Haslerud, Sturla; Magnussen, Liv Heide; Joensen, Jon; Lopes-Martins, Rodrigo Alvaro Brandao; Bjordal, Jan Magnus (2015-06-01). “The efficacy of low-level laser therapy for shoulder tendinopathy: a systematic review and meta-analysis of randomized controlled trials”. Physiotherapy Research International. 20 (2): 108–125. doi:10.1002/pri.1606. hdl:1956/17899. ISSN 1471-2865. PMID 25450903.
- Page, MJ; Green, S; Kramer, S; Johnston, RV; McBain, B; Buchbinder, R (Oct 1, 2014). “Electrotherapy modalities for adhesive capsulitis (frozen shoulder)”. The Cochrane Database of Systematic Reviews. 10 (10): CD011324. doi:10.1002/14651858.CD011324. PMID 25271097.
- Nampo, Fernando Kenji; Cavalheri, Vinícius; Ramos, Solange de Paula; Camargo, Enilton Aparecido (2016-01-01). “Effect of low-level phototherapy on delayed onset muscle soreness: a systematic review and meta-analysis”. Lasers in Medical Science. 31 (1): 165–177. doi:10.1007/s10103-015-1832-4. ISSN 1435-604X. PMID 26563953.
- Ferraresi, C; Hamblin, MR; Parizotto, NA (1 November 2012). “Low-level laser (light) therapy (LLLT) on muscle tissue: performance, fatigue and repair benefited by the power of light”. Photonics & Lasers in Medicine. 1 (4): 267–286. doi:10.1515/plm-2012-0032. PMC 3635110. PMID 23626925.
- Karlsson, M. R.; Diogo Löfgren, C. I.; Jansson, H. M. (2008). “The Effect of Laser Therapy as an Adjunct to Non-Surgical Periodontal Treatment in Subjects with Chronic Periodontitis: A Systematic Review”. Journal of Periodontology. 79 (11): 2021–2028. doi:10.1902/jop.2008.080197. PMID 18980508.
- Sgolastra, F.; Petrucci, A.; Severino, M.; Gatto, R.; Monaco, A. (2013-06-01). “Lasers for the treatment of dentin hypersensitivity: a meta-analysis”. Journal of Dental Research. 92 (6): 492–499. doi:10.1177/0022034513487212. ISSN 1544-0591. PMID 23609160.
- Eslamian, L.; Borzabadi-Farahani, A.; Hassanzadeh-Azhiri, A.; Badiee, M.R.; Fekrazad, R. (2013-01-20). “The effect of 810-nm low-level laser therapy on pain caused by orthodontic elastomeric separators”. Lasers in Medical Science. 29 (2): 559–564. doi:10.1007/s10103-012-1258-1. PMID 23334785.
- Ren, Chong; McGrath, Colman; Yang, Yanqi (2015-09-01). “The effectiveness of low-level diode laser therapy on orthodontic pain management: a systematic review and meta-analysis”. Lasers in Medical Science. 30 (7): 1881–1893. doi:10.1007/s10103-015-1743-4. ISSN 1435-604X. PMC 4562996. PMID 25800534.
- He, W. L.; Yu, F. Y.; Li, C. J.; Pan, J.; Zhuang, R.; Duan, P. J. (2015-08-01). “A systematic review and meta-analysis on the efficacy of low-level laser therapy in the management of complication after mandibular third molar surgery”. Lasers in Medical Science. 30 (6): 1779–1788. doi:10.1007/s10103-014-1634-0. ISSN 1435-604X. PMID 25098769.
- Oberoi, Sapna; Zamperlini-Netto, Gabriele; Beyene, Joseph; Treister, Nathaniel S.; Sung, Lillian (2014-01-01). “Effect of prophylactic low level laser therapy on oral mucositis: a systematic review and meta-analysis”. PLOS One. 9 (9): e107418. Bibcode:2014PLoSO…9j7418O. doi:10.1371/journal.pone.0107418. ISSN 1932-6203. PMC 4157876. PMID 25198431.
- Rangwala, Sophia; Rashid, Rashid M. (Feb 2012). “Alopecia: a review of laser and light therapies”. Dermatology Online Journal. 18 (2): 3. ISSN 1087-2108. PMID 22398224.
Since then, a number of studies have suggested the use of lasers as an effective way to treat alopecia, particularly androgenetic alopecia and alopecia areata, but there is still a paucity of independent, peer-reviewed blinded clinical trials.
- Avci, Pinar; Gupta, Gaurav K.; Clark, Jason; Wikonkal, Norbert; Hamblin, Michael R. (February 2014). “Low-Level Laser (Light) Therapy (LLLT) for Treatment of Hair Loss”. Lasers in Surgery and Medicine. 46 (2): 144–151. doi:10.1002/lsm.22170. ISSN 0196-8092. PMC 3944668. PMID 23970445.
- Gupta, AK; Daigle, D (April 2014). “The use of low-level light therapy in the treatment of androgenetic alopecia and female pattern hair loss”. The Journal of Dermatological Treatment. 25 (2): 162–3. doi:10.3109/09546634.2013.832134. PMID 23924031.
- Zarei, Mina; Wikramanayake, Tongyu C.; Falto-Aizpurua, Leyre; Schachner, Lawrence A.; Jimenez, Joaquin J. (2015-12-21). “Low level laser therapy and hair regrowth: an evidence-based review”. Lasers in Medical Science. 31 (2): 363–71. doi:10.1007/s10103-015-1818-2. ISSN 1435-604X. PMID 26690359.
- Smoot, Betty; Chiavola-Larson, Laura; Lee, Jeannette; Manibusan, Hidelisa; Allen, Diane D. (2015-06-01). “Effect of low-level laser therapy on pain and swelling in women with breast cancer-related lymphedema: a systematic review and meta-analysis”. Journal of Cancer Survivorship: Research and Practice. 9 (2): 287–304. doi:10.1007/s11764-014-0411-1. ISSN 1932-2267. PMID 25432632.
- Barrett, S (June 17, 2009). “A Skeptical Look at Low Level Laser Therapy”. Quackwatch. Archived from the original on December 9, 2009.
- Borzabadi-Farahani, A. (2016-07-22). “Effect of low-level laser irradiation on proliferation of human dental mesenchymal stem cells; a systemic review”. Journal of Photochemistry and Photobiology B: Biology. 162: 577–582. doi:10.1016/j.jphotobiol.2016.07.022. PMID 27475781.
- “Doggone Joints: Laser Therapy for Pet Arthritis”. ABC News. 2011-02-23. Retrieved 2016-07-19.
- Robinson, Narda G. (2013), “Complementary and Alternative Veterinary Medicine: Laser Therapy”, The Merck Veterinary Manual, 11th edition.
- McKenzie, Brennen (2016), “The Laser Craze: What Is the Evidence for Low-level Laser Therapy?” [SA222]; Western Veterinary Conference, Proceedings of the WVC 88th Annual Conference, Mandalay Bay Convention Center, Resort and Casino, Las Vegas, NV, March 6–10, 2016.
- McKenzie, Brennen (2016), “WVC 2016: The Laser Craze”, The SkeptVet.
- McKenzie, Brennen (2015), “Evidence Update: Cold Laser Therapy for Dogs & Cats”; The SkeptVet.