Red light therapy (RLT), also known as photobiomodulation (PBM), is a non-invasive treatment that uses specific wavelengths of light, typically ranging from 660 to 850 nanometers (nm), delivered by low-level lasers or light-emitting diodes (LEDs). This light stimulates biological processes in the body, leading to beneficial effects. This article evaluates the scientific evidence regarding RLT’s potential to treat or prevent symptoms associated with the common cold, medically referred to as an Acute Upper Respiratory Infection (URI).
How Red Light Interacts with Cells
The fundamental mechanism of red light therapy begins at the cellular level within the mitochondria. Photons of red and near-infrared light are absorbed by a specific molecule called Cytochrome c Oxidase (CCO). This enzyme plays a significant part in cellular respiration, the process by which the cell generates energy.
When the light stimulates CCO, it helps release inhibitory molecules like nitric oxide that may be temporarily binding to the enzyme. This action increases the efficiency of the electron transport chain. The result is an increase in the production of Adenosine Triphosphate (ATP). This boost in cellular energy allows cells to perform functions of repair, regeneration, and defense more effectively.
Modulating the Body’s Immune Response
The enhancement of cellular energy translates into potential benefits for the body’s defense systems, which are highly energy-dependent. Immune cells, such as macrophages and lymphocytes, require substantial amounts of ATP to replicate, move, and function optimally when fighting an infection. By improving mitochondrial function, RLT may help these immune cells mount a more efficient and stronger defense against viral invaders like those causing the common cold.
Red light therapy is also known for its anti-inflammatory effects, which can directly address cold symptoms. Inflammation is a primary driver of symptoms like sinus pressure, sore throat, and congestion in a URI. RLT can reduce inflammation by modulating the activity of pro-inflammatory markers, helping to shift the response toward an anti-inflammatory state.
Furthermore, the light can induce vasodilation (the widening of blood vessels), leading to improved circulation and blood flow in the treated areas. Enhanced circulation can more effectively deliver necessary immune cells and nutrients to affected tissues, such as the nasal passages and throat. This improved blood flow may also help clear cellular waste and reduce swelling, which contributes to congestion.
Clinical Findings Regarding Common Colds
While RLT is not a direct cure that eliminates cold viruses, the evidence suggests it may help manage symptoms and potentially shorten the duration of the illness. Studies focusing on the application of light directly to the nasal passages, a technique known as rhinophototherapy, have shown encouraging results for specific symptoms. For example, patients treated with light in the 660 nm range have experienced decreased nasal resistance and reported better airflow and reduced sneezing frequency.
The primary benefit appears to be in reducing inflammation in the mucosal tissues of the upper respiratory tract. RLT helps alleviate pressure and congestion in the sinuses and nasal cavity. Some trials involving external and intranasal light application for sinusitis have demonstrated significant improvement in symptoms like headache, nasal congestion, and overall quality of life.
Much of the existing research on RLT focuses on symptom management, such as sinus congestion, rather than eliminating the underlying viral infection. However, by enhancing cellular function and reducing inflammation, RLT supports the body’s natural processes, which can lead to a faster recovery. Consistent and early use, ideally within the first 24 hours of feeling symptoms, is suggested to maximize potential benefits.
Safe Use and Treatment Protocols
When using red light therapy for cold symptoms, the application is typically targeted to the areas experiencing discomfort. Common target zones include the sinuses, applying the light over the cheekbones and forehead, and the throat or neck for a sore throat or cough. For general symptoms, some protocols suggest applying the light to the upper chest to address deep-tissue inflammation.
Recommended treatment times range from five to 20 minutes per targeted area, performed once or twice daily during the active phase of the cold. The specific wavelength is often a combination of red light (around 660 nm) for surface tissues and near-infrared light (810 nm to 850 nm) for deeper penetration into the sinus cavities.
RLT is generally considered non-invasive and safe for home use. However, users must always wear eye protection when using high-powered light panels. It is also recommended to start with shorter sessions to allow the body to adjust and to consult a healthcare professional, especially if symptoms worsen or if there are any underlying health conditions.