Red light therapy (also known as photobiomodulation) is often thought of as simply another skin treatment. Carefully selected wavelengths of red and near-infrared light interact with your cells, supporting natural repair processes, energy production and healthy cellular function. While many of these biological effects begin within minutes of treatment, the greatest benefits are achieved through regular, repeated sessions over time.
1. Light Penetrates the Skin and Reaches Your Cells
Different wavelengths of light penetrate to different depths within the skin. Red light (approximately 620–700 nm) primarily targets the skin and superficial tissues. Near-infrared light (approximately 760–900 nm) penetrates deeper into muscles and connective tissue. These wavelengths are absorbed by structures inside the mitochondria—the "power stations" of our cells. One important target is an enzyme called cytochrome c oxidase, which plays a key role in cellular energy production.
2. Mitochondria Produce More Cellular Energy
When light is absorbed by the mitochondria, it can temporarily improve the efficiency of cellular respiration. This allows cells to produce more:
ATP (Adenosine Triphosphate)
ATP is the body's energy currency and is required for almost every cellular process, including:
- Cell repair
- Protein synthesis
- Collagen production
- Skin renewal
- Wound healing
- Immune function
Rather than adding energy to the body, red light helps your own cells produce energy more efficiently.
3. Nitric Oxide is Released
Red light also helps release nitric oxide that is temporarily bound within the mitochondria. Nitric oxide is a natural signalling molecule that:
· Relaxes blood vessels
· Improves microcirculation
· Enhances oxygen delivery
· Improves nutrient transport
· Supports removal of cellular waste products
Many people notice a gentle warming sensation after treatment, reflecting these changes in local circulation.
4. Cell-to-Cell Communication Increases
As cells become more metabolically active, they begin communicating more effectively with neighbouring cells through biochemical signalling pathways.
These signalling molecules help coordinate:
- Tissue repair
- Immune responses
- Cellular maintenance
- Recovery following injury or inflammation
- This improved cellular communication helps maintain healthy tissue function.
5. Beneficial Cellular Signalling is Activated
A common misconception is that all reactive oxygen species (ROS) are harmful. In reality, very small amounts are produced naturally by healthy mitochondria.Following red light therapy, these small increases in ROS act as important signalling molecules that activate the body's own protective mechanisms.
These pathways support:
- Cellular repair
- Antioxidant defence systems
- Stress resistance
- Healthy ageing of tissues
This process is known as hormesis, where a small biological stimulus encourages the body to become stronger and more resilient.
What Happens Inside the Skin?
One of the most important effects occurs in specialised cells called fibroblasts.
Fibroblasts are responsible for producing:
- Collagen
- Elastin
Components of the extracellular matrix that provide skin with structure and strength. Research suggests that photobiomodulation can increase fibroblast activity, which may help support:
- Improved collagen synthesis
- Better skin firmness
- Enhanced elasticity
- Improved wound healing
- Healthier skin architecture
These changes develop gradually with repeated treatments rather than after a single session.
Reducing Inflammation
Photobiomodulation also appears to influence the body's inflammatory response.
Studies suggest it may help regulate inflammatory signalling molecules, supporting a healthier tissue environment.
This may contribute to improvements in:
- Redness
- Skin recovery
- Irritation
- Healing after procedures
- General skin resilience
Rather than simply "switching inflammation off," red light helps the body regulate inflammation more effectively.
Improved Blood Flow
Improved microcirculation is one of the most consistently observed effects.
Better circulation helps deliver:
- Oxygen
- Nutrients
- Growth factors
- Immune cells
while also assisting with the removal of metabolic waste products.
This creates a favourable environment for tissue repair and regeneration.
Why 10 Minutes Can Be Enough
Photobiomodulation follows what scientists call a biphasic dose response (sometimes called the Arndt-Schulz principle).
This means:
Too little light produces little effect. The correct dose produces the greatest benefit. Excessive exposure does not necessarily improve results and, in some cases, may reduce the therapeutic response. For many clinical LED devices, around 10 minutes delivers an effective dose of light energy to activate cellular processes. The exact treatment time depends on the wavelength, power output and total energy delivered (measured in J/cm²), so different devices may require different treatment durations. Consistency is far more important than longer sessions.
The Take-Home Message
During a 10-minute red light therapy session:
Red and near-infrared light penetrate the skin. Mitochondria absorb the light. Cellular ATP production becomes more efficient. Nitric oxide is released, supporting healthy blood flow. Cell signalling pathways are activated. Fibroblasts are stimulated to support collagen production. Inflammatory signalling becomes better regulated. Microcirculation improves, helping deliver oxygen and nutrients. The body's natural repair mechanisms begin to respond. While many of these biological processes begin within minutes, visible improvements in skin quality, wound healing and collagen remodelling occur gradually through repeated treatments over weeks and months.
Key Point: Red light therapy does not force the skin to change. Instead, it supports the body's own natural repair systems, helping cells function more efficiently and creating an environment that promotes healthier, stronger and more resilient skin over time.
