Photobiomodulation (or PBM) is a form of light therapy that uses red or near-infrared light or a low-level laser over the brain, inside the nasal cavity, or over injuries or wounds (1). The light is used to heal, improve tissue repair in wounds, bones and tendons, reduce pain and inflammation and restore and stimulate multiple physiological processes which repair damage caused by injury or disease (1). The healing occurs wherever the beam is applied. The light stimulates the cell’s natural healing and pain relief processes.
Originally PBM was called “low level laser therapy or LLLT”. It has also been called red light therapy (RLT), low level light therapy (LLLT), soft laser therapy, cold laser therapy, bio stimulation and photonic stimulation. Actual lasers are not required because LEDs or light emitting diodes work equally well (2).
For much of the time since its discovery approximately 50 years ago, the mechanism of action or how PBM worked was not really known (2). It is now understood how PBM works on the cellular level.
PBM works by producing a biochemical effect in cells that strengthens the mitochondria (2). The primary site of light absorption in cells has been identified as the mitochondria and PBM works by increasing the mitochondria’s potential (3).
All cells in the body have mitochondria. Mitochondria are commonly called the powerhouses of the cells as they provide most of the energy of the cell. They produce ATP (adenosine triphosphate), which is the chemical responsible for energy release within cells which promote cellular and physiological functions including injury repair and pain relief.
When a cell is damaged through injury or trauma, the mitochondria’s efficiency is impaired. As a result, less ATP will be produced. The reduction in ATP will decrease the cells’ healing time dramatically.
When exposed to infra-red light/low level laser at the right frequency and intervals, the mitochondria will be stimulated to immediately begin to increase the production of ATP (2). By increasing the function of the mitochondria using PBM, a cell can make more ATP (2). With more energy, cells can function more efficiently, rejuvenate themselves and repair damage.
How can it be used?
Photobiomodulation is used for a huge variety of health issues.
Cognitive performance or brain injury: PBM is being used to treat traumatic brain injury, stroke, neurodegenerative diseases (Parkinson’s, Alzheimer’s and dementia) and psychiatric disorders (4). PBM has anti-inflammatory effects on the brain which can help with brain injuries (4).
Wound healing: PBM has been used on both acute wounds and chronic non-healing wounds such as diabetic ulcers (4). What has been found is faster healing and reduced inflammation (4).
Arthritis: Arthritis involves significant inflammation of the arthritic joint. Sometimes this inflammation is systemic as well. Studies have found that swelling and inflammation is reduced with PBM (4). Both osteoarthritic and rheumatoid arthritis have been ‘successfully treated with PBM’ (4).
Muscles: PBM can work well on muscles; it helps to heal muscle injuries and reduce muscle soreness and pain after excessive exercise (4). Unsurprisingly, PBM has many applications in sports. Light delivered to muscles before exercise and after exercise can increase sports performance in athletes (5). Studies have found that PBM can increase muscle mass gained after training, and decrease inflammation and oxidative stress in muscles (5). PBM increases the amount of work and power that can be produced by muscles and can increase the speed of recovery after exercise. This is very helpful in the intense training regimens of top athletes. PBM can also be used for enhancement of performance in amateur and recreational athletes.
Inflammatory Pain: PBM can reduce inflammatory pain and decrease pro-inflammatory markers, chemicals produced at the site of pain and inflammation (4). In fact, PBM is perhaps most relevant in cases of inflammation and inflammatory disorders (4).
Lung inflammation and asthma: PBM has been found to reduce acute lung inflammation and lung edema (4). Another study concluded that in asthma, the reduced lung inflammation and the beneficial effects on lung airways of PBM seem to be a result of increased anti-inflammatory chemicals and less mucous in the airways (6).
Abdominal fat, obesity and type 2 diabetes: The use of PBM to fight one of the biggest health problems of the modern age; obesity, excess fat deposits and type 2 diabetes; is also starting to take off (2). A study on mice found that PBM reduced inflammation in abdominal fat and significantly reduced blood sugar (4).
Cancer: PBM has been found to be effective in reducing the side effects of cancer treatment therapy (7). For example, oral mucositis is a common side effect of cancer treatments, particularly chemotherapy and radiation (7). It is when the mucosal lining of the mouth begins to break down, which can lead to ulcers in the mouth. It results in several problems, including pain, an inability to eat causing poor nutrition, and increased risk of infection due to open sores in the mucus area of the mouth. PBM helps to reduce this issue as well as other complications with cancer treatment (8). An important concern was whether the use of PBM for relief of side effects might encourage the growth of malignant cells and cancerous tumors, given its healing and strengthening effect on cells in general (8). Research has shown that this is not the case and that light can directly damage the tumor, enhance other cancer therapies and stimulate the patient’s immune system (7). There are some clinical trials showing increased survival in cancer patients who received PBM therapy (7).
PBM has been shown in studies to improve Achilles tendinopathy (less pain and reduced inflammation) and thyroiditis (overall improved thyroid function, a reduction in autoimmune antibodies to thyroid and reduced inflammation of the thyroid) (4).
Psoriasis, a chronic autoimmune disease of the skin, is greatly improved with PBM because of its anti-inflammatory effects (4).
Hair loss: PBM is successful in treating the various types of hair loss; alopecia areata, male pattern baldness and chemotherapy induced alopecia (4). Stimulation of hair regrowth is now well established (2).
PBM can also improve cognitive performance, memory and mood (2). It is expected that further research in this area will be emerging soon.
PBM is also useful for cosmetic and aesthetic improvements (2). Improvement of fine lines and wrinkles in the face is growing in popularity, as some people seek aesthetic improvements (2).