Low Level Laser (Cold Laser) Therapy


Low level laser therapy (LLLT), also known as cold laser therapy, is a well researched, evidence-based intervention that has long been used in pain management. Some of its uses include reducing inflammation, decreasing edema, promoting healing of wounds, reducing joint pain, and treating neurological disorders as well as nerve pain.

LLLT is a non-invasive, pain-free, light-based therapy that uses infrared light to assist the body’s healing process. Some of its uses include reducing inflammation, decreasing edema, promoting healing of wounds, reducing joint pain, and treating neurological disorders as well as nerve pain.

History of Laser Treatment

In the early 1960, the ruby and helium-neon laser was invented. Some time after this, Endre Mester at the Semmelweis University in Budapest showed that apply laser light to the back of shaven mice accelerated the return of hair growth.  Mester latter applied his findings to human patients, showing that lasers could assist with healing skin ulcers. This was the beginning of low level laser therapy, which is also called photobiomodulation because of the way it interacts with the body. The broader field, called photobiology, is the study of how light affects living things, and includes studies of single-celled organisms, plants, animals and humans.

In the 1970s serious research began both in Russia and in the USA. By the 1980s, due to numerous positive reports, laser started to gain recognition as an effective pain management methodology.

How Does Laser Therapy Work?

LLLT involves exposing cells or tissues to low levels of near infrared light – most often red colored light. It is called low level or cold laser because the light involved does not cut or burn like lasers used in surgery. Despite decades of research, the mechanism of action concerning how LLLT works physiologically is poorly understood. This is not uncommon in medicine. Many drugs, such as anti-depressants, Acetaminophen, Metformin, Pyrazinamide, and even aspirin, are also poorly understood in terms of their mechanism of action.

Four major effects of LLLT, based on current research, are:

aerobic respiration image
  1. Wound Healing and Tissue Regeneration
  2. Pain Reduction
  3. Inflammation Management
  4. Immune System Enhancement

What is known is that LLLT acts on an important part of the cell called the mitochondria. This is the “power center” of the cell that produces energy. The mitochondria absorb photons from the laser, which results in the production of energy in a form called adenosine triphosphate or ATP. This energy can then be used by the tissue to perform important cellular tasks. LLLT also influences the cell in other ways, which help to decrease inflammation and modulate pain. Another way to say this is that LLLT induces a photochemical reaction in the cell, which is called biostimulation or photbiomodulation.

By increasing energy available in this readily accessible form, laser light is able to greatly stimulate the biological function of cells, tissue, and systems and even raise overall vital energy throughout the individual. This is particularly true if the laser therapy is focused on stimulating acupuncture points.

How is LLLT Used in Therapy?

LLLT is often used in physical medicine on an anatomical basis. This means that the laser is applied over a specific region of the body to help with problems and issues in that area.

Laser therapy can also be used in a different way: to stimulate acupuncture points. In this application, a very low level laser (5mW) in the near infrared range (600-1070nm) is applied to various acupuncture points in order to optimize physiological functions. In Chinese medicine theory, it is believed that the life force or “qi” is carried in special channels or meridians in the body. Problems with the flow of qi in the body leads to disease, according to the Chinese medical model. Appropriately stimulating acupuncture points assists in diminishing disordered or dysfunctional qi flow.  Needles, tuning forks, or even fingers can be used to stimulate acupuncture points. Research indicates that lasers can also successfully stimulate these points, leading to positive therapeutic outcomes.

Recent studies on laser acupuncture have included advanced brain imaging, as well as several other modern protocols for measuring various physiological effects to the body. These studies show that laser acupuncture has physiological effects, not only locally, but also in the central nervous system. The effects were only detected when the laser was actually working, similar to the effects of acupuncture needles.

Multiple research studies have shown good effects of laser acupuncture for the following conditions: traumatic brain injury/concussion, carpal tunnel syndrome, musculoskeletal conditions including trigger points,  joint pain, and stroke-related issues.


  • Wound healing was one of the first applications of LLLT, when HeNe lasers were used by Mester et al. to treat skin ulcers. LLLT is believed to affect all three phases of wound healing. LLLT is believed to promote wound healing by inducing the local release of cytokines, chemokines, and other biological response modifiers that reduce the time required for wound closure, and increase the mean breaking strength of the wound. Not all studies have had a positive outcome, however, so research is ongoing in this area.
  • LLLT has had some success with neck pain. A review of 16 randomized clinical trials including a total of 820 patients found that LLLT reduces acute neck pain immediately after treatment, and up to 22 weeks after completion of treatment in patients with chronic neck pain.
  • LLLT has been successful with alleviating pain and treating chronic joint disorders.  A study of 88 randomized controlled trials indicated that LLLT can significantly reduce pain and improve health in chronic joint disorders such as osteoarthritis, patellofemoral pain syndrome, and mechanical spine disorders. However, the authors of the study urge caution in interpreting the results because of the wide range of patients, treatments, and trial designs involved.
  • LLLT is hypothesized to be beneficial in the treatment of traumatic brain injury (TBI). In addition to its effects in increasing mitochondrial activity and activating transcription factors, LLLT could benefit TBI patients by inhibiting apoptosis, stimulating angiogenesis, and increasing neurogenesis. Experiments carried out with two mouse models indicated that LLLT could reduce the brain damaged area at 3 days after treatment, and treatment with a 665 nm and 810 nm laser could lead to a statistically significant difference in the Neurological Severity Score (NSS) of mice that had been injured.
  • One of the most commercially successful applications of LLLT is the stimulation of hair regrowth in balding individuals. The photobiomodulation activity of LLLT can cause more hair follicles to move from telogen phase into anagen phase. The newly formed hair is thicker and also more pigmented. In order to make the application of light to the head more user-friendly and increase patient compliance, companies have developed “laser caps.”

Other Effects

  • The immune response is stimulated
  • Lymphatic drainage is improved
  • The histamine response is positively altered
  • Production of growth hormone is increased

It should be noted that many other positive physiological activities are modulated and extensive research is currently in progress to fully explore these changes.