High-Intensity Laser Therapy (HILt)

Red LaserHigh-Intensity Laser Therapy (HILT) is a non-invasive and painless method of light therapy that, according to many studies, may be an effective therapeutic method for pain relief, healing, and cell regeneration. HILT is a form of light stimulation based on the Low-Level Laser Therapy (LLLT) principle. Studies in light therapy are showing that HILT may have the potential to offer a robust and non-addictive form of acute pain management. And that it can be effective, especially in the treatment of sports injuries, muscle injury or joint distortion, and lower back pain or disorders in the cervical region causing neck pain. Unlike Low-level Laser Therapy, the high power and choice of the right wavelength of the HILT allow for deep tissue penetration. Through a natural process of energy transfer, it shows that it may have a positive effect on healing and tissue regeneration. The main difference between HILT and Low-Level Laser Therapy (LLLT) is that the more powerful beams (power >500 mW) are irradiated to penetrate deeper, bringing a desired high amount of multi-directional energy to deep tissues in a short time. Also, application techniques, treatment time, and device cost differences between these two generations of laser therapy.


The start of the laser can be traced back to 1917 when Albert Einstein suggested the concept of stimulated emission. At first, there were operational lasers, the equivalent to lasers working in the microwave region of the spectrum, and after that, the optical laser was presented. Charles Townes, Aleksandr Prokhorov, and Nikolay Basov were awarded the 1964 Nobel Prize in Physics for their work on the development of lasers. Arthur Schawlow and Charles Townes, Bell Labs/Columbia University, are generally credited with ‘inventing’ the laser. However, Gordon Gould is considered by many to be its inventor as he coined the term LASER (Light Amplification by Stimulated Emission of Radiation) and eventually was awarded patents on many types of lasers. In 1960 Theodore Maiman at Hughes Research Laboratories, USA, demonstrated the first optical laser. This demonstration was a pivotal moment globally, and groups from around the world took up the challenge to develop laser systems leading to them being used in a broad range of applications.

Side effects

A therapeutic High-Intensity Laser is generally considered safe, but protective eyewear is obligatory throughout the therapy. With the increasing power of the High-Intensity Laser, caution is in place as to its thermic effects, which on the one hand, provide delightful treatment, but, if not monitored and used by a trained operator, can damage the tissue. Other possible side effects from the therapy may occur in:

  • Pregnancy: Pregnant women are recommended not to undergo the procedure since its effects on unborn children are unknown.
  • Eyes: Everyone present should wear appropriate safety spectacles.
  • People with epilepsy: Be aware that light might trigger a seizure in photosensitive epileptic patients.


High-Intensity Laser Therapy has been used more recently in the therapeutic protocols of pain management. Physiotherapists use HPLT basically on the presumption that the laser’s energized cells increase the healing rate. The research indicates that HILT may have positive incomes, such as:

  • Reduces pain
  • Speeds Tissue Repair and Cell Growth
  • Softens Scar Tissue
  • Resets Chronic Pain Cycle
  • Reduces Swelling
  • Improved Blood Flow
  • Improves Nerve Function


Nineteen studies were included for qualitative and quantitative assessment. The average power of the lasers used in the reviewed studies was between 0.6 to 25 W. Most studies (68%) used a pulsed laser with energy density varying from 0.25 to 150 J/cm2. Approximately 94% of the included articles (n=18) revealed positive effects of HILT on pain. The management of acute and chronic pain is based on different mechanisms, and we should apply more irradiance of laser therapy in chronic pain conditions. From the results, adding thermal and non-thermal agents to HILT may enhance the effects of laser therapy.

The results in one study regarding the efficacy of HILT in reducing pain in knee osteoarthritis demonstrated an immediate solid, cumulative, and long-lasting (for three months) effect of High-Intensity Laser Therapy on pain management. The results of this study indicate that HILT could be a promising new possibility in treating knee osteoarthritis. Although the results are very optimistic, more tests are needed to fully acknowledge the possible therapeutical effects of HILT.

Source: “Effectiveness of High-Intensity Laser Therapy for Reduction of Pain in Knee Osteoarthritis

Frequently Asked Questions

What is the difference between LLLT and HILT?

The output power of fewer than 0.5 Watts is called Low-Level Laser Therapy (LLLT), whereas lasers with an output power >500 mW are HILT.

chrome firefox IE edge safari opera android appleinc