According to the U.S. Centers for Disease Control and Prevention (CDC), an estimated 900,000 people in the United States are affected by venous thromboembolism (VTE) each year, which includes both deep vein thrombosis (DVT) and pulmonary embolism (PE) [1]. These conditions are serious, potentially life-threatening manifestations of abnormal blood clotting, and they highlight the critical importance of maintaining healthy circulatory and coagulation functions.
As interest in non-invasive, biologically supportive therapies continues to grow, Red Light Therapy (RLT), also known as photobiomodulation (PBM), has gained attention for its wide-ranging effects on cellular metabolism, inflammation, and microcirculation. While commonly explored for benefits related to skin rejuvenation, muscle recovery, and chronic pain, one increasingly relevant area of focus is how red and near-infrared light may influence vascular function, blood flow, and the coagulation cascade.
This article explores the potential role of red light therapy in supporting hemostatic balance, particularly how it may contribute to healthy blood clot resolution, endothelial function, and vascular homeostasis, without promoting pathological thrombosis. By examining the photobiological mechanisms of action, we aim to clarify how RLT interacts with the circulatory system at the molecular and physiological level, and address common concerns related to its safety in individuals with clotting risks.
The Physiology of Blood Clotting (Hemostasis)
Blood clotting, or hemostasis, is the body’s natural process for stopping bleeding after a blood vessel is injured. This complex but essential function allows the body to prevent blood loss while also maintaining normal blood flow throughout the circulatory system. A healthy clotting process depends on balance, clots must form quickly when needed but also dissolve properly once healing is complete to avoid harmful blockages.
Hemostasis occurs in three main stages:
- Vessel Constriction (Vasoconstriction)
When a blood vessel is damaged, it quickly narrows to reduce blood flow to the area. This response is triggered by signals from the blood vessel lining (endothelium) and surrounding tissues. - Platelet Plug Formation
Special blood cells called platelets rush to the site of injury and stick to the exposed tissue. Once attached, they become activated, change shape, and release chemical signals that attract more platelets. This forms a temporary plug to seal the opening. - Coagulation and Fibrin Clot Formation
In the final step, a series of proteins in the blood (called clotting factors) work together in a chain reaction known as the coagulation cascade. This leads to the formation of fibrin, a strong, thread-like protein that reinforces the platelet plug, creating a stable clot.
After the blood vessel is healed, the body naturally breaks down the clot through a process called fibrinolysis, which helps restore normal blood flow.
How Red Light Therapy May Support Healthy Circulation and Clot Regulation
While Red Light Therapy (RLT) does not trigger blood clotting, it may support several key aspects of circulatory health that help maintain a healthy balance in the clotting system.
Red Light Therapy works by delivering specific wavelengths of red and near-infrared light to the body’s tissues. These wavelengths are absorbed by cellular structures, especially mitochondria, which are responsible for producing energy. One important mitochondrial enzyme, cytochrome c oxidase, responds to light by improving the production of ATP.
This cellular boost leads to several beneficial effects:
- Improved blood flow: RLT increases the release of nitric oxide, a molecule that helps blood vessels relax and widen. Better blood flow means oxygen and nutrients can travel more easily, while also reducing the chances of blood pooling or stagnating, two risk factors for clot formation.
- Healthier blood vessels: The light supports endothelial cells, which line the inside of blood vessels. Strong, healthy endothelium helps regulate clotting and prevents unwanted clot formation.
- Reduced inflammation: Chronic inflammation can damage blood vessels and increase the risk of clotting. RLT helps lower the levels of certain inflammatory molecules, creating a healthier environment in the blood vessels.
- Support for natural clot breakdown: By enhancing energy production and circulation, RLT may help the body more efficiently carry out fibrinolysis, the process that breaks down clots after they’ve served their purpose.
Red Light Therapy does not increase the risk of blood clots. On the contrary, it may help support healthy blood flow, reduce inflammation, and promote the body’s natural ability to manage clotting and healing, all without interfering with the body’s normal protective responses.
How Red Light Therapy Affects Blood Flow and Circulation
Red Light Therapy (RLT), or photobiomodulation (PBM), has well-documented effects on improving circulation and vascular function. These benefits are rooted in how specific wavelengths of red and near-infrared light interact with blood components and vascular tissues, leading to a cascade of physiological responses that support healthy blood flow, tissue oxygenation, and cellular metabolism.
At the core of these effects is the stimulation of mitochondrial function, particularly the enzyme cytochrome c oxidase, which plays a key role in producing adenosine triphosphate (ATP). Enhanced ATP availability allows cells, including those in blood vessels, immune cells, and red blood cells, to function more efficiently, especially under stress or injury.
Improved Red Blood Cell Function and Deformability
Red Light Therapy has a significant impact on red blood cell (RBC) physiology, which is critical for oxygen transport and overall circulatory efficiency. A review titled Narrative Review of Russian, Ukrainian and English-Language Publications Investigating the Effects of Photobiomodulation on Red Blood Cell Physiology noted:
“The majority of articles indicated beneficial changes in RBC structure and function following exposure to PBM, including increased osmotic resistance, normalization of membrane permeability, decreased free radical oxidation and concentration of intermediate products of lipid peroxidation, reduced phospholipase A2 membrane activity, and normalization of the viscoelastic properties of RBCs and erythrocyte deformability index.” [2]
These changes help red blood cells travel more easily through the smallest capillaries, improving microcirculation and reducing the likelihood of blood cell aggregation, a factor that can contribute to clot formation in compromised vascular environments.
Protection Against Oxidative Stress in the Bloodstream
During medical procedures such as extracorporeal circulation (ECC), where blood is routed outside the body through machines, red blood cells are often exposed to mechanical and oxidative stress, which can lead to cellular damage. However, a study titled Low-Level Light Therapy Protects Red Blood Cells Against Oxidative Stress and Hemolysis During Extracorporeal Circulation found that:
“We presented the applicability of the LLLT with R/NIR radiation to blood trauma reduction during ECC.” [3]
This suggests that Red Light Therapy may protect blood cells from damage, potentially extending their functional lifespan and improving oxygen-carrying capacity even in high-stress scenarios.
Stabilizing Blood Glucose and Supporting Vascular Health
Beyond red blood cells, RLT has also demonstrated systemic metabolic effects. In a study titled Light Stimulation of Mitochondria Reduces Blood Glucose Levels, researchers found that:
“Consequently, PBM with 670 nm light can be used to reduce blood glucose spikes following meals. This intervention may reduce damaging fluctuations of blood glucose on the body.” [4]
Stable blood glucose levels are essential for vascular health, as frequent spikes and crashes can cause oxidative damage to blood vessels and promote a pro-inflammatory, pro-thrombotic environment. By reducing post-meal glucose fluctuations, Red Light Therapy may indirectly protect the vascular system and support healthier circulation over time.
In combination, these effects illustrate how Red Light Therapy supports circulation at multiple levels:
- Enhances red blood cell flexibility and oxygen transport
- Reduces oxidative stress in the bloodstream
- Promotes vasodilation via nitric oxide release
- Stabilizes metabolic function, reducing vascular strain
- Supports the health and repair of the endothelial lining
Together, these mechanisms help ensure that blood flows freely and efficiently throughout the body, while also minimizing the risk of unwanted clot formation. For individuals concerned with cardiovascular health, poor circulation, or clot-related conditions, Red Light Therapy offers a non-invasive way to support the body’s natural vascular regulation systems.
Benefits of Red Light Therapy for Circulatory Health
Red Light Therapy (RLT), through its targeted delivery of red and near-infrared wavelengths, offers a range of scientifically supported benefits for the circulatory system. While RLT does not promote coagulation or clot formation, it plays an important supportive role in vascular health by enhancing the physiological mechanisms that maintain proper blood flow, prevent stasis, and aid in the resolution of clots when appropriate.
The circulatory benefits of RLT include:
Enhanced Endothelial Function
The endothelium, which lines the interior surface of blood vessels, plays a central role in regulating vascular tone, blood flow, and anti-thrombotic signaling. Red Light Therapy stimulates nitric oxide (NO) release from cytochrome c oxidase (CCO) in the mitochondria of endothelial cells. This NO release promotes vasodilation, improves oxygen delivery, and inhibits unnecessary platelet adhesion and aggregation, supporting a balanced hemostatic response.
Improved Red Blood Cell Integrity and Flexibility
Red Light Therapy positively influences erythrocyte deformability, allowing red blood cells to pass more easily through narrow capillaries. Research shows that RLT can normalize cell membrane permeability, increase osmotic resistance, and reduce oxidative damage, factors that contribute to better microvascular circulation and reduced risk of erythrocyte clumping, which can precede clot formation.
Support for Natural Clot Resolution (Fibrinolysis)
Once a clot has served its purpose in sealing a vessel injury, the body must break it down through fibrinolysis. RLT enhances mitochondrial ATP production, providing energy for cellular processes involved in tissue repair and remodeling. This may support the natural breakdown of fibrin clots and contribute to vascular recovery post-injury.
Reduction of Inflammation and Oxidative Stress
Chronic inflammation and oxidative damage are key contributors to endothelial dysfunction and thrombotic risk. RLT helps modulate reactive oxygen species (ROS) and downregulates pro-inflammatory cytokines such as TNF-α and IL-6, creating a more stable vascular environment that is less prone to abnormal clot formation.
Improved Capillary Perfusion and Blood Flow
By promoting vasodilation and reducing blood viscosity, RLT enhances capillary perfusion, ensuring efficient delivery of oxygen and nutrients while minimizing circulatory stagnation. This is particularly beneficial for individuals at risk of clotting due to a sedentary lifestyle, vascular disease, or metabolic dysfunction.
Red Light Therapy supports circulatory health through a multifaceted approach that includes improved endothelial performance, healthier red blood cells, balanced inflammatory signaling, and enhanced tissue oxygenation. Rather than promoting coagulation, RLT helps regulate the biological systems that prevent unwanted clot formation and support natural clot resolution, making it a valuable modality for those seeking non-invasive support for their vascular and cardiovascular well-being. Explore our Wavelength Benefits Guide for specific conditions.
Red Light Therapy (RLT) offers a scientifically supported, non-invasive method to enhance circulatory function and support the body’s natural regulation of blood clotting. Rather than initiating coagulation or posing a risk for thrombosis, RLT interacts with the body at the cellular and mitochondrial level, promoting physiological balance within the vascular system.
By stimulating cytochrome c oxidase in the mitochondria, Red Light Therapy enhances ATP production, increases nitric oxide availability, and improves redox signaling, all of which contribute to vasodilation, microvascular circulation, and endothelial integrity. These changes help reduce the risk of blood stasis, platelet hyperactivity, and inflammatory vascular damage, which are key contributors to pathological clot formation.
RLT improves the flexibility and resilience of red blood cells, supports capillary perfusion, and enhances the body’s capacity for fibrinolysis, the natural breakdown of blood clots after healing. These effects make RLT a valuable modality for individuals seeking to maintain optimal vascular health, particularly those managing risk factors such as metabolic dysfunction, inflammation, or impaired circulation.
Red Light Therapy plays a protective and regulatory role in the body’s clotting mechanisms by supporting endothelial health, improving blood flow, and aiding in tissue recovery. When used correctly, it complements the body’s natural systems to maintain a healthy balance between clot formation and clot resolution, without promoting harmful clot development.
References
[1] Data and Statistics on Venous Thromboembolism. (2025, 27 January). Venous Thromboembolism (Blood Clots). https://www.cdc.gov/blood-clots/data-research/facts-stats/index.html
[2] Liebert A, Pang V, Caagby D, Arshinikova L, Kiat H. Narrative Review of Russian, Ukrainian and English-Language Publications Investigating the Effects of Photobiomodulation on Red Blood Cell Physiology. Photobiomodul Photomed Laser Surg. 2022 Feb;40(2):98-111. doi: 10.1089/photob.2021.0069. Epub 2021 Dec 27. PMID: 34962147.
[3] Walski T, Drohomirecka A, Bujok J, Czerski A, Wąż G, Trochanowska-Pauk N, Gorczykowski M, Cichoń R, Komorowska M. Low-Level Light Therapy Protects Red Blood Cells Against Oxidative Stress and Hemolysis During Extracorporeal Circulation. Front Physiol. 2018 May 31;9:647. doi: 10.3389/fphys.2018.00647. PMID: 29904353; PMCID: PMC5991292.
[4] Powner MB, Jeffery G. Light stimulation of mitochondria reduces blood glucose levels. J Biophotonics. 2024 May;17(5):e202300521. doi: 10.1002/jbio.202300521. Epub 2024 Feb 20. PMID: 38378043.
