Dr Jenna Macciochi Discusses the Science Behind Red Light Therapy

Red light therapy, also known as photobiomodulation (PBM) is a non-invasive treatment that uses low-level light in the red (660nm) and 850nm invisible near-infrared (NIR) spectrum. If we break that down, ‘photo’ refers to light, ‘bio’ refers to your biology and ‘modulation’ is to modulate your biology with light. Although it may sound sci-fi, it’s actually based on the profound science of sunlight. We already know that UV wavelength in sunlight is super important for vitamin D production. But UV is only one wavelength in sunlight that’s beneficial. This article will discuss the role of red light (the visible red part of the spectrum that humans can see with our eyes) and near-infrared light which is just outside of the visible light spectrum that humans can see with our eyes, so it’s actually invisible to us.

PBM therapy has been studied for it's benefits on a wide range of health conditions including improving tissue healing, reducing pain and unwanted inflammation, and enhancing cognitive function.

Shining red light on parts of your body sounds a bit sci-fi! But, before you click away, let’s keep an open mind. This article will cover the science of PBM, how it works, what it treats and why it might just be what you need right now.

How does red light therapy work?

Red and near-infrared light have a very, very special, very unique set of mechanisms by which they act on our cells. they can penetrate below the skin, even when we have light clothes on. Red light penetrates more shallowly, just under the top layer of the skin and the longer infrared light penetrates several centimetres below the surface of our skin reaching our internal organs and tissues. The light should be around 3 inches away from the skin and a session on the affected area is usually between 10 - 20 minutes, 1 time per day.

The benefits are thought to be down to several different molecular pathways. With an evolving field of science such as this, it’s important to state that we haven’t got the mechanism of action fully worked out yet. Here is what we know so far...

PBM stimulates the production of adenosine triphosphate (ATP) in the mitochondria of cells. ATP is the primary energy source for cells, and increased ATP production can lead to improved cellular function and metabolism. This increase in mitochondrial activity also comes with a downside because this increased mitochondrial activity consequently leads to an increase in the production of reactive oxygen species (ROS). ROS have the potential to cause oxidative stress. But here is the cool thing - when ROS react with a molecule called serotonin, which is produced by the mitochondria, it results in sub-cellular melatonin production. Melatonin is a hormone that is primarily produced by the pineal gland in the brain. It plays a key role in regulating the sleep-wake cycle and has antioxidant and anti-inflammatory properties. However, recent research has shown that melatonin is also produced in the mitochondria of our cells, known as sub-cellular melatonin. Unlike sleepy pineal melatonin, this actually happens when we are out in the infrared light produced by the sun, not when it gets dark. The evolutionary origins of this are hypothesised to be down to our need for the antioxidant effects of melatonin at the mitochondria of our cells during the day. Sub-cellular melatonin produced in the mitochondria has been shown to have several benefits. It can scavenge ROS and protect cells from oxidative stress, tissue damage and inflammation.

Exposure to infrared light via PBM can increase the production of this sub-cellular melatonin. Mitochondrial sub-cellular melatonin production is therefore an important mechanism by which PBM exerts its therapeutic effects.

Other proposed mechanisms include:

  • Activate cellular signaling pathways, such as the PI3K/Akt and MAPK/ERK pathways, which can promote cell survival and proliferation.
  • Reduce inflammation by inhibiting the production of pro-inflammatory cytokines and promoting the release of anti-inflammatory cytokines.
  • Promote the formation of new blood vessels, which can improve blood flow to damaged tissues and promote healing.
  • Increase the release of nitric oxide (NO) from cells. NO is a signalling molecule that plays a role in vasodilation, immune function, and neurotransmission, among other functions.
  • Promote DNA repair in cells, which can help to prevent mutations and cellular damage that can lead to disease.
  • Modulate neural activity by promoting the release of neurotransmitters and improving the function of neural mitochondria. This can be beneficial for conditions such as neuropathy, stroke, and traumatic brain injury.

Some of the conditions that PBM has been shown to be useful for include:

Pain Management

One of the most studied applications of PBM is pain management. Numerous clinical trials have shown that PBM can effectively reduce pain and inflammation in various conditions, including osteoarthritis, rheumatoid arthritis, low back pain, and fibromyalgia. PBM has also been shown to have a positive effect on nerve function, which can be beneficial in conditions such as neuropathy.

Wound Healing

PBM has been shown to accelerate wound healing and reduce scarring. It works by increasing blood flow to the affected area, promoting the formation of new blood vessels, and stimulating the production of collagen, which is essential for tissue repair.

Skin Health

PBM has been shown to have a positive effect on skin health, including reducing the appearance of wrinkles and fine lines, improving skin tone and texture, and promoting the healing of acne and other skin conditions.

Sports Performance and Recovery

PBM has been shown to enhance athletic performance and speed up recovery from sports-related injuries. It can improve muscle strength, endurance, and recovery time, as well as reduce muscle soreness and inflammation.

Neurological Conditions

PBM has been studied for its potential use in treating a range of neurological conditions, including traumatic brain injury, stroke, and Parkinson's disease. It has been shown to promote nerve regeneration, reduce inflammation, and improve cognitive function.

Oral Health

PBM has been shown to have a positive effect on oral health, including reducing pain and inflammation associated with periodontal disease and promoting the healing of oral wounds.


Not a replacement for the sun.

Many of us have jobs or life circumstances that keep us indoors for large parts of the day so we do not benefit from the red and infrared produced by the sun. While PBM offers targeted benefits and holds huge therapeutic potential, it is not a replacement for getting outside in the sunshine (safely).

We all tend to feel better after going outside and that’s no coincidence. Strong observational evidence shows that avoiding sun exposure is a risk factor for all-cause mortality. We have, broadly speaking, a light deficiency in our modern lifestyles which is impacting us on various biological levels from vitamin D deficiency, to circadian disruption, mitochondrial health and more.

In summary

PBM is a non-invasive therapy that uses low-level light to modulate cellular function and is shaping up to be a promising therapy with a wide range of potential health benefits. The scientific literature and evidence supporting the use of PBM for health are growing. While more research is needed to fully understand its mechanisms of action and potential applications, PBM has been shown to be a safe, non-invasive, and effective treatment option for a range of health conditions.

Should you try PBM?

So there you have it, a comprehensive look at PBM. While PBM is becoming more common in clinical settings, it is also possible to use it at home. I have been using PBM for many years and I have found it helpful to keep on hand for so many aspects of my health such as targeted injuries, skin issues and infections. Dosing red light therapy will depend on the device you are using and the tissue that you are targeting. Always refer to the safety information and guidance provided by the manufacturer.

Immunologist | Fitness Instructor | Health Coach

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