Photobiomodulation, also known as low-level laser light therapy (LLLT) and red light therapy, involves the application of focused red and near infrared light to the body to elicit a photochemical response. This has been shown to have a therapeutic effect that will promote healing and tissue repair, combat pain and reduce inflammation.

An Introduction to Photobiomodulation

If you break down the word photobiomodulation you have “photo” meaning light, “bio” relating to the body or living organisms, and “modulation” meaning the exertion of a modifying influence. So put very simply, photobiomodulation is the use of light to influence the function of cells within the body.

Photobiomodulation (PBM) therapy was first developed in 1967 when it was discovered that low-level lasers had therapeutic qualities. It was discovered that low powered lasers, not just the high powered thermal lasers used in surgery, had a place in medicine. Thus low-level laser treatment began to be studied and trialled alongside other forms of photomedicine and laser surgery.

The photobiomodulation process involves the application of focused light delivered by a low power laser or another light source, at a frequency that can be absorbed by the body. When photons are absorbed by cells they increase cellular energy and metabolism, triggering a number of photochemical reactions that have therapeutic outcomes including reducing pain and promoting wound healing.

Phototherapy was originally delivered by low power lasers, hence it was commonly known as Low Level Laser Light Therapy (LLLT). However, technological advances mean that phototherapy can now be delivered by different forms of light devices including light emitting diodes (LEDs) and broadband light. The term Photobiomodulation therapy covers the use of different sources of light energy for therapeutic outcomes, not just low power lasers.

How It Works. What Is The Photobiomodulation Process?

The effect of photobiomodulation comes from the interaction of photons (a massless particle of light carrying energy and momentum) with the mitochondria within our cells. In order for photobiomodulation to occur, light energy must be able to reach the damaged tissue.

Photobiomodulation or low level laser therapy utilizes red and near infrared light from non-ionizing light sources. The wavelength of light is important as different wavelengths on the electromagnetic spectrum penetrate the body to different levels. Visible red light (400 – 700 nm) and near infrared light (700 – 1100 nm) offer the deepest penetration and as such have the best therapeutic effects.

As well as needing the correct wavelengths of light, power density or irradiance is also an important factor in the effectiveness of photobiomodulation (PBM) therapy. In order for photobiomodulation to occur dose response studies have shown that a threshold level of photons must be delivered, otherwise there will be no significant therapeutic effect. Higher irradiance (power) allows more photons to be delivered to cells at any given wavelength. Thus increasing power can also reduce treatment times.

High quality devices are designed so that practitioners are able to utilize both the wavelength and irradiance to maximize the therapeutic effect.

Photons that enter the cells interact with the Cytochrome C complex found in the cell’s mitochondria. Mitochondria are cell-bound organelles that generate the energy needed to power a cell’s biochemical reactions. The energy created is stored in adenosine triphosphate (ATP) molecules. When cells are damaged ATP production is reduced, impairing cellular function and slowing the cell’s metabolism. When light is absorbed by the cell it stimulates the electron transport chain and ATP production resulting in reduced oxidative stress.

As well as increasing the production of ATP, low-level light therapy also regulates the production of nitric oxide (NO) and modulates levels of reactive oxygen species (ROS) both of which play an important role in cellular signaling pathways. Faster signalling reduces inflammation, improves healing and helps to prevent cell death within the target tissue.

What is Photobiomodulation Good For?

Although low-level laser therapy has been around for many years, significant progress has been made in recent years in understanding the mechanisms of action, and there is increased recognition that many different diseases and conditions could be treated with photobiomodulation therapy.

There are now thousands of clinical studies and scientific reports looking at the mechanism and effect of photobiomodulation therapy. PBM therapy can be used to treat neck pain, soft tissue damage, oral mucositis (a common side effect of cancer treatment), ulcers and depression. There are even studies looking at using transcranial photobiomodulation to treat neurological conditions such as traumatic brain injury, Alzheimer’s disease and Parkinson’s disease.

How do PBM treatments work for so many different conditions and diseases? The simple answer to this is that Photobiomodulation therapy takes cells from a state of low ATP and high oxidative stress to a state of high ATP and low oxidative stress. This enables the body’s natural healing process to take effect. Cells are taken from a proinflammatory state to an anti-inflammatory state helping the body and brain to repair itself.

So while suggesting a single medical device delivering something as innocuous as light could support healing in so many different ailments might sound like something out of a sci-fi movie. When you understand how that light impacts the cells it is easier to see how that could be the starting point for healing multiple conditions.

One of the benefits of photobiomodulation therapy is that it is painless, non-invasive and doesn’t interact with other treatments making it an attractive option as part of a combined therapy plan. For example, when looking to treat muscle or joint pain, PBM can be used alongside physical therapy and medication without adverse effects.

Is Photobiomodulation FDA Approved?

When considering the issue of FDA approval, whether photobiomodulation is FDA approved, it has been approved for the treatment of muscle and joint pain.