Photobiology of Red Light Therapy: How Wavelengths Affect Skin Healing and Anti-Aging


The healing properties of sunlight were first discovered and employed by the Ancient Egyptians and Greeks. However, researchers had not considered the potential effects of various light frequencies on cellular processes before the 20th century. Low-level laser treatment, otherwise called photobiomodulation or red light treatment, is a new improvement in skin health management that utilizes the impacts of light.

 The basis of this type of treatment is in the area of photobiology, which is characterized as "the logical investigation of the safe or harmful interactions between light and living organisms, especially if the light is in the frequencies of infrared or visible light." It is an especially intriguing field which concentrates on the mechanism behind the effects of light on the metabolic processes occurring inside the cell. This includes processes such as the synthesis of vitamin D from sunlight or photosynthesis in plants, as well as processes that we are simply starting to comprehend, such as how red light treatment affects complexion and how it affects collagen. Before we look into what red light treatment means for the skin, understanding the science behind it is significant.

 The science behind Photobiology:

 Light is made of photons, which are essentially energy packets. During the interaction between light and an organism, photons are absorbed into the cells of the body through special molecules, which are called chromophores. These are found in a variety of cellular structures, including proteins, enzymes, and pigments. They possess a differentiated ability to absorb light of specific wavelengths, which is particularly helpful because light of different wavelengths possesses different levels of energy. This enables them to absorb lights of different energies to trigger a series of biochemical processes which cause changes in cellular function.

 Depending on their wavelengths, different lights can penetrate the skin to different extents. Lights of longer wavelengths can penetrate deeper into the skin, e.g. red light, which possesses a wavelength in the range of 630-700 nm, can penetrate the skin to a moderate depth. Near-infrared light in the range wavelength 800-900 nm penetrates even deeper, and this range of wavelengths provides skincare professionals with the option to target specific chromophores within the skin as needed.

Understanding Wavelengths and Skin Penetration:

Red light therapy uses wavelengths ranging from 630-700 nm while near-infrared light uses between 800-900 nm. These have been selected for their particular properties and their capacity to impact the skin cells of various layers. The skin has three layers which interact with light in various ways. 

  • The epidermis: This is the skin's outermost layer, which serves as a barrier against the environment. It is relatively transparent and enables light to pass through it, albeit some frequencies are more retained than others, for example, UVB beams. UV rays, which have shorter wavelengths, are mostly absorbed by the epidermis, where they cause DNA damage and sunburn. However, longer ones such as red light can reach deeper layers of the skin.
  • The dermis: Present beneath the epidermis, the dermis is rich in the following: collagen, elastin and blood vessels. This layer, which provides structural support to the skin, is the primary target of red light therapy. The particular wavelengths used in this therapy reach the dermis where they interact with cells to influence various metabolic processes.
  • The hypodermis: It contains blood and lymph vessels, nerves, sweat glands, and sebaceous glands which regulate the sebum (oil) of skin. It also contains fat cells which are important to insulate the body and regulate body temperature. Red light therapy increases nitric oxide (NO) resulting in increased blood circulation.

 Understanding light-cell interactions is very important to know if one is to tailor the most effective treatment for their skin issues. By selecting specific wavelengths, one can easily target the desired depth of the skin to correct their problems. Let us look into the advantages of red light therapy and its impact on the skin’s health.

Advantages of Red Light therapy:

  • Cellular Energy Production and Red Light Therapy:

Often described as the “powerhouse” of the cell, mitochondria are tiny organelles which float around in the cytoplasm. Their main purpose is to use nutrients to produce ATP, thereby enabling the cell to remain operative. This is done through a process known as “oxidative phosphorylation”. ATP production is vital for maintaining cellular health and carrying out various physiological functions of the cell. Thus, we must understand the influence of red light therapy on ATP synthesis and consequently on skin healing and rejuvenation.

 Red light therapy operates on the principle of the ability of light to interact with mitochondria to stimulate and enhance the process of ATP synthesis. By exposing the skin to red or near-infrared light, a series of metabolic reactions is initiated which usually culminates in a boost of ATP synthesis. This happens in the following way: 

  • Photobiomodulation begins when mitochondrial chromophores absorb light's wavelengths.
  • Enzymes and proteins involved in electron transport chains are activated as a result.
  • Hence electron flow is stimulated.
  • Subsequently, more ATP is synthesized.

 Some more ways in which red light affects ATP synthesis include:

  • activating the transcription enzymes that play a role in the production of ATP by encouraging the mitochondria to produce reactive oxygen species, which are molecules that serve as cell signaling.
  • Boosting the expression of the proteins and enzymes that are needed to make adenosine triphosphate.

 The increased accessibility of ATP significantly affects the different cell processes required for skin rejuvenation. Adenosine triphosphate is a cell's primary energy source which powers different processes like DNA repair and protein production, hence it helps the skin heal by allowing the cells to regenerate and function more effectively.

 In addition, the production of collagen, a skin protein that is necessary for maintaining elasticity and rigidity, requires adenosine triphosphate. The collagen-producing fibroblast cells gain sufficient energy to produce new collagen fibers by stimulating ATP production. This leads to a reduction in wrinkles, restoring skin structures and promoting a youthful complexion.

 The impact of red light therapy extends beyond wound healing and collagen synthesis. Due to higher levels of ATP, cellular metabolism is enhanced, which not only allows cells to function optimally but also aids the process of skin rejuvenation by promoting cellular detoxification and supporting the removal of waste products and cellular debris.

  •  Effect of Red Light Therapy on Skin Collagen:

Collagen, which is the most abundant protein in the body, acts as a structural foundation. It provides firmness, strength, and elasticity to the skin. Understanding its role and production is crucial to comprehend and appreciate the influence of red light therapy in promoting its production.

 Our skin is supported by the extracellular matrix. This is primarily a complex mesh of proteins and other molecules which not only support but also nourish the skin cells. It also provides a basic framework which allows the skin to resist stretching and be able to maintain its shape. Collagen fibers, however, act like scaffolding by providing support to the two primary layers of the skin, the dermis, and epidermis. The key purpose of collagen is to contribute to the skin’s youthfulness by giving it smoothness and suppleness. The development of collagen normally diminishes with age, which might be accelerated by natural and extraneous elements, like genetic disposition, pollution, lifestyle choices, and sun exposure.

 Red light therapy has rapidly emerged as a promising approach to stimulate collagen production and rejuvenate the skin. When fibroblasts are exposed to light, they respond by increasing their activity and producing more collagen fibers, which leads to increased elasticity and firmness of the skin, helping to restore the skin’s youthfulness.

 Red light therapy further aids in the remodeling of existing collagen fibers as it activates enzymes known as MMPs (matrix metalloproteinases). These play a role in breaking down and rebuilding collagen. Red light therapy can help regulate MMP activity, therefore causing a balanced collagen turnover which not only prevents unrestricted collagen degradation but also supports the production of healthy collagen fibers.

 Another positive impact that red light therapy can have on collagen production is its influence on the cross-linkages within the protein. Large numbers of collagen cross-linkages lead to strengthened and more organized fibers being produced which further increases the resilience of the skin.

 Additionally, the treatment also causes the production of other crucial components of the extracellular matrix, such as hyaluronic acid and elastin. While elastin provides elasticity to the skin, hyaluronic acid hydrates the skin and maintains skin plumpness. By promoting the synthesis of these components, the treatment boosts skin rejuvenation.

 Clinical studies have proved red light therapy to be an effective and promising treatment in terms of collagen synthesis and boosting skin integrity. For instance, a study published in the Journal of Clinical and Aesthetic Dermatology demonstrated that red light therapy enhances collagen density and also causes a significant improvement in the skin texture of the participants. Other studies have reported similar findings. This further highlights the potential of red light therapy as a non-invasive method for promoting collagen production.

 It is also worthwhile mentioning that the effectiveness of collagen synthesis through red light therapy is dependent on factors such as wavelength used, treatment duration, and individual response. Typically, consistency in treatment is advised for maximum results.

  •  Enhancing Blood Circulation for Skin Healing:

 Our blood can be thought of as a tissue, as it contains cells that have important roles in protecting our body. Among these are red blood cells (which transport respiratory gasses), white blood cells (which circle our body to protect it against microbes and infections), and platelets (cells that are involved in clotting our blood and mending wounds). Moreover, the blood conveys nutrients to our cells and removes metabolic waste products from the cells leading to detoxification of the body hence healthy skin.

 Sluggish blood circulation can have a detrimental impact on the skin, leading to the accumulation of toxins and oxygen depletion. This hinders the healing processes, leads to acne breakouts, and causes overall lackluster skin.

 Red light therapy utilizes specific wavelengths of red and near-infrared light to interact with blood vessels to initiate beneficial responses: 

  • Angiogenesis:

This refers to the formation of new blood capillaries. Capillaries are the smallest blood vessels which are responsible for the exchange of nutrients, respiratory gasses, and toxins with surrounding tissues. The treatment promotes the creation of proteins which are responsible for encouraging the growth and proliferation of new capillaries. This improves blood supply to the skin.

 Capillary formation leads to improved oxygenation and nutrient delivery. Oxygen is vital for respiration and ATP synthesis while nutrients have an important role in aiding tissue repair and supporting cellular functions which speeds up the healing process in the skin. 

  • Vasodilation:

Vasodilation means an increase in the diameter of the blood vessels. When light is applied to the skin, nitric oxide is released which causes blood vessels to relax and expand. This leads to increased blood flow and aids in the enhanced delivery of oxygen and nutrients along with the removal of metabolic waste.

 A study published in the Journal of Investigative Dermatology conducted a study to observe the effects of red light therapy on blood circulation. The study concluded the positive impact of red light therapy on blood circulation, which has led to confirmation that red light therapy holds great promise as an invaluable tool in the perusal of skin rejuvenation by promoting blood circulation.

 Anti-inflammatory effects:

An added advantage of red light therapy is its anti-inflammatory effects. Inflammation is an automatic response of the body to wounds and infections, however, if persistent, it may impede healing. Red light therapy hinders the production of pro-inflammatory molecules and regulates the activity of immune cells to create a favorable environment for blood circulation and tissue repair. 

 Immune cells such as macrophages are crucial to the body’s protective mechanisms. This is partially due to the cell signaling molecules they release, which include pro-inflammatory cytokines. Red light therapy downgrades the production of these chemicals, such as tumor necrosis factor-alpha (TNF-α) thereby dampening the inflammatory response.

On the other hand, they also boost the production of anti-inflammatory cytokines e.g. interleukin-10, to counteract the pro-inflammatory signals. It also regulates the synthesis of cyclooxygenase enzymes, which in turn causes a decrease in the production of inflammatory mediators.

Red light therapy also stimulates the release of antioxidants within cells. Different antioxidants neutralize harmful free radicals. By enhancing the antioxidant defenses within cells, red light therapy helps to minimize inflammation.

 Effects of Red Light Therapy:

The effects of red light therapy vary from individual to individual. However, most individuals deem it a pleasant sensation, similar to basking in warm, gentle light. The treatment sessions are short as they last between 5 to 20 minutes depending on the protocol and device used. Users also report a mild sensation of warmth, however it is deemed tolerable whereas some users may notice a red glow to their skin. Another sensation reported is a feeling of well-being and relaxation, which adds to the pleasantry of the experience.

 A list of benefits reported by users include:

  • Reduction in the appearance of fine lines and wrinkles
  • Reduce Acne breakouts and redness
  • Improved skin tone
  • Accelerated wound healing
  • Relief from joint pain and muscle soreness

 It is important to note that the effects observed depend on factors such as individual skin concerns, skin type, treatment parameters, and overall health.

 Risks associated with Red Light Therapy:

While red light therapy is undoubtedly one of the most innovative treatments of its kind, it lags behind its counterpart, microcurrent therapy, due to more research being required to properly understand its risks and limitations. With that being said, the following are some of the risks associated with red light therapy that should be kept in mind while deciding to opt for the treatment: 

  • Skin sensitivity: Some individuals report skin sensitivity or have skin conditions that may be aggravated post-session. If you have a history of skin disorders, active infections, or open wounds, it is advised to consult a dermatologist before booking a session.
  • Eye Protection: Direct exposure to light can harm the eyes so it is crucial to wear appropriate eye gear such as goggles during the session.
  • Pregnancy or medical conditions: For pregnant women or people with medical conditions such as thyroid disorders or epilepsy, it is important to ask your healthcare provider before booking a treatment session.
  • Photosensitivity: Red light therapy uses visible red light or near-infrared light: both of these have low photosensitivity potential. However, it is advised to avoid simultaneous usage of other photosensitive creams and medications and to avoid treatments that may enhance sensitivity to light. If in doubt, consult your healthcare provider.

 There are a number of at-home red light therapy skin devices available in the market. The EvenSkyn Mirage: Pro LED Phototherapy Face Mask is one of the best at-home red light therapy devices. It is a premium anti-aging device that uses red light phototherapy at 630nm depth to directly help increase the natural production of collagen, resulting in smoother and more even skin texture. The mask is designed to provide users with a professional quality experience at home. The EvenSkyn Mirage has also been approved by FDA. However, it is always recommended to consult a dermatologist before using any such device.


Red light therapy is an emerging alternative to microcurrent therapy and has many appealing qualities such as painlessness, its non-invasive nature, and the myriad of benefits it offers. However, it should also be kept in mind that the avenue of red light therapy is relatively unexplored and the treatment should only be used if supported by your dermatologist.

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