There have been thousands of studies supporting the effectiveness of LED low level light therapy (LLLT), here are just a few examples.
Article: Mechanisms of Low Level Light Therapy
Author: Michael R. Hamblin of Harvard Medical School
Highlights: Mitochondria are thought to be a likely site for the initial effects of light, leading to increased ATP production, modulation of reactive oxygen species, and induction of transcription factors. These effects in turn lead to increased cell proliferation and migration (particularly by fibroblasts), modulation in levels of cytokines, growth factors and inflammatory mediators, and increased tissue oxygenation. The results of these biochemical and cellular changes in animals and patients include such benefits as increased healing of chronic wounds, improvements in sports injuries and carpal tunnel syndrome, pain reduction in arthritis and neuropathies, and amelioration of damage after heart attacks, stroke, nerve injury, and retinal toxicity. (from the 2nd paragraph)
In LLLT, the question is no longer whether light has biological effects, but rather how energy from therapeutic lasers and LEDs work at the cellular and organism levels, and what are the optimal light parameters for different uses of these light sources. (under section 1, History)
There are perhaps three main areas of medicine and veterinary practice where LLT has a major role to play (Figure 1). These are (i) wound healing, tissue repair and prevention of tissue death; (ii) relief of inflammation in chronic diseases and injuries with its associated pain and edema; (iii) relief of neurogenic pain and some neurological problems. (under section 3. BIOCHEMICAL MECHANISMS)
Article: Is light-emitting diode phototherapy (LED-LLLT) really effective?
Authors: Won-Serk Kim and R Glen Calderhead, their conclusion was:
Conclusion: Provided an LED phototherapy system has the correct wavelength for the target cells, delivers an appropriate power density and an adequate energy density, then it will be at least partly, if not significantly, effective. The use of LED-LLLT as an adjunct to conventional surgical or nonsurgical indications is an even more exciting prospect. LED-LLLT is here to stay.
Article: Effects of low-power light therapy on wound healing: LASER x LED
Authors: Maria Emília de Abreu Chaves,1 Angélica Rodrigues de Araújo, André Costa Cruz Piancastelli, and Marcos Pinotti
Conclusion: The reviewed studies show that phototherapy, either by LASER or LED, is an effective therapeutic modality to promote healing of skin wounds. The biological effects promoted by these therapeutic resources are similar and are related to the decrease in inflammatory cells, increased fibroblast proliferation, angiogenesis stimulation, formation of granulation tissue and increased collagen synthesis. In addition to these effects, the irradiation parameters are also similar between LED and LASER. Importantly, the biological effects are dependent on such parameters, especially wavelength and dose, highlighting the importance of determining an appropriate treatment protocol.
Article: Red (660 nm) and infrared (830 nm) low-level laser therapy in skeletal muscle fatigue in humans: what is better?
Authors: Patrícia de Almeida, Rodrigo Álvaro Brandão Lopes-Martins, Thiago De Marchi, Shaiane Silva Tomazoni, Regiane Albertini, João Carlos Ferrari Corrêa, Rafael Paolo Rossi, Guilherme Pinheiro Machado, Daniela Perin da Silva, Jan Magnus Bjordal, and Ernesto Cesar Pinto Leal Junior
Conclusion: We conclude that both red and infrared LLLT are effective in delaying the development of skeletal muscle fatigue and in enhancing skeletal muscle performance. The optimal parameters of application, as well as dose–response patterns for several wavelengths still need to be identified in further studies. Further studies are also needed to identify the specific mechanisms by which each wavelength acts.
Article: A Controlled Trial to Determine the Efficacy of Red and Near-Infrared Light Treatment in Patient Satisfaction, Reduction of Fine Lines, Wrinkles, Skin Roughness, and Intradermal Collagen Density Increase
Authors: Alexander Wunsch and Karsten Matuschka
Conclusion: The treated subjects experienced significantly improved skin complexion and skin feeling, profilometrically assessed skin roughness, and ultrasonographically measured collagen density. The blinded clinical evaluation of photographs confirmed significant improvement in the intervention groups compared with the control.
Article: 830 nm light-emitting diode low level light therapy (LED-LLLT) enhances wound healing: a preliminary study
Authors: Pok Kee Min, MD PhD and Boncheol Leo Goo
Conclusion: 830 nm LED-LLLT successfully brought about accelerated healing in wounds of different etiologies and at different stages, and successfully controlled secondary infection. LED-LLLT was easy and pain-free to apply, and was well-tolerated by all patients. The good results warrant the design of controlled studies with a larger patient population.
Article: Does Phototherapy Enhance Skeletal Muscle Contractile Function and Postexercise Recovery? A Systematic Review
Authors: Paul A Borsa, PhD, ATC, FACSM, Kelly A Larkin, PhD, CAT(C), and Jerry M True, DC, FIACN
Conclusion: Phototherapy administered before resistance exercise consistently has been found to provide ergogenic and prophylactic benefits to skeletal muscle.