Facts and benefits of red light therapy

Red and near-infrared light are absorbed by the skin at different depths and may influence the activity of the mitochondria, the structures that produce
energy in cells. This may contribute to increased production of ATP, which cells use
in their natural processes, including the production of collagen and elastin, two important proteins that give skin its firmness, structure and elasticity.

A laboratory study using red and near-infrared LED light showed increased production of ATP, collagen and elastin in skin cells and skin tissue. The findings support
the mechanism behind how these wavelengths may influence the skin's
structure and elasticity.

Lee et al. (2007) conducted a randomised, placebo-controlled, double-blind split-face study using red and near-infrared LED light. The study showed
improvements in, among other things, fine lines, wrinkles, skin elasticity and markers
linked to collagen production.

A systematic research review of 31 randomised controlled trials shows the breadth of clinical research on LED light in dermatology. The review describes promising results in several areas, while the effect is influenced by factors such as wavelength, dose and
treatment protocol.

In summary

Research shows that red light therapy may contribute to:

• Smoother, more elastic skin
• Reduction of fine lines and wrinkles
• Prevention of sagging skin over time
• Increased skin density and a strengthened skin barrier

With age, the body's natural production of collagen and elastin declines, while the skin's ability to renew its cells weakens.

In a randomised controlled study with 136 participants, Wunsch and Matuschka examined the effect of red and near-infrared light on the appearance of the skin. After 30 treatments, increased collagen density, smoother skin and improvements in fine lines and wrinkles were measured compared with the control group.

Light at specific wavelengths can penetrate deep into the skin and may help to reduce visible signs of ageing such as fine lines, wrinkles, sagging skin and uneven skin tone. It also has an anti-inflammatory effect, which is important because inflammation accelerates skin ageing.

A study using pulsed LED red light therapy (660 nm) showed a 31% increase in type 1 procollagen levels and an 18% reduction in MMP‑1, an enzyme that breaks down collagen. Clinical assessments also showed a significant reduction in both wrinkle depth and skin roughness after 12 treatments.

Several studies have also shown that LED light treatment stimulates the skin to produce more fibroblasts, which in turn leads to increased production of collagen and elastin.

Overall, the research supports that red and
near-infrared light may influence processes that are important for the skin's collagen production and structure. With regular use, this may over time help the skin feel smoother, firmer and more elastic.

In summary:

Research shows that red light therapy may contribute to

• Reduced lines and wrinkles
• More even skin tone and texture
• More glow and vitality
• Increased firmness and elasticity

Research suggests that red light therapy (photobiomodulation) may influence inflammatory processes in the skin and modulate local immune activity.

In a study with 28 participants, red and blue light therapy were compared in the treatment of acne. The improvement rate for inflammatory and non-inflammatory lesions was 51.5% and 17.3% respectively in the group receiving red light therapy, versus 26.4% and 10.0% in the blue light therapy group.

Another study documented that red and near-infrared light reduce inflammation in the skin by activating the body's own defence mechanisms.

These findings have made photobiomodulation an active area of research for several inflammatory skin conditions, including acne, eczema and psoriasis. The results are promising, but the clinical evidence varies between the different conditions.

With regular use, red light therapy may help reduce acne breakouts by calming inflammation and supporting the skin's natural healing processes. It may also ease symptoms of eczema and psoriasis by reducing irritation and itching, while strengthening the skin barrier.

In summary:

In short, research suggests that photobiomodulation may influence biological processes that are important for skin repair and the inflammatory response. Although the results are promising, the clinical evidence varies between different skin conditions.

Some studies suggest that red light therapy (photobiomodulation) may influence biological processes involved in the body's inflammatory response. Research suggests that PBM may affect the energy production of the mitochondria, reduce oxidative stress and modulate the production of signalling molecules involved in inflammation.

A number of experimental studies have shown that PBM may affect the levels of various cytokines and other signalling molecules that regulate inflammatory processes. In cell and animal studies, reduced production of several pro-inflammatory cytokines and increased activity in cellular defence systems have been observed, including signalling pathways linked to Nrf2.

One study showed that treatment with red and green light reduces the production of inflammatory cytokines in skin cells. The effect is mediated partly through activation of Nrf2, the body's main defence against oxidative stress and inflammation. At the same time, the light dampens the activation of the skin's immune cells and thereby helps calm local immune reactions.

A comprehensive scientific review also shows that photobiomodulation (PBM), of which red light therapy is a part, may reduce inflammation at cell level by affecting the energy production of the mitochondria, reducing oxidative stress and balancing immune activity in inflamed tissue. Documented effects have been seen in the skin, joints, muscles and nervous system.

A comprehensive review article published in Lasers in Medical Science in 2025 summarises research suggesting that photobiomodulation may modulate the immune response by influencing macrophages, T cells, dendritic cells and inflammatory signalling pathways, among other things.

Taken together, the research suggests that red light therapy may play a role as a supportive treatment for inflammation-related skin and tissue conditions.

In summary:

The existing research suggests that photobiomodulation may:

• modulate biological processes linked to inflammation
• affect the production of inflammatory signalling molecules
• reduce oxidative stress
• support normal tissue repair processes

Although the results are promising, the clinical evidence varies between different areas of use, and more large, well-controlled clinical studies are needed.

Research suggests that red and near-infrared light may affect microcirculation and biological processes involved in pain and inflammation.

When red light therapy is used locally on areas such as the back, neck, shoulders or joints, many people report less pain and better function. Studies have examined PBM in both acute and chronic pain conditions, including osteoarthritis, muscle pain and some forms of neuropathic pain.

A clinical study examined the effect and safety of high-intensity LED light treatment in 23 patients with hand osteoarthritis. Participants received eight treatments over four weeks, aimed at the most painful finger joints. The results showed a clear reduction in pain, and the researchers concluded that the treatment was both safe and effective.

A larger review study has gathered extensive evidence on how photobiomodulation (PBM), of which red light therapy is a part, with near-infrared light relieves pain and inflammation in joint conditions such as osteoarthritis and rheumatoid arthritis. Research suggests that PBM may affect biological processes in inflamed joints, including through modulation of inflammatory signalling molecules and cellular repair processes. The review also shows that PBM affects specialised cells in the joints and contributes to better function, without the side effects that often come with medication.

Several other studies support the effect:

• A randomised double-blind study with 18 participants showed significant pain relief (VAS) after LED treatment (red 660 nm + infrared 850 nm) three times a week for two weeks, compared with the control group.
• In a study of 30 young women who received cluster laser and LED treatment three times a week for four weeks, a significant reduction in pain and improved functional ability were reported.
• A pilot study with 10 participants also found a clear reduction in stiffness after LED treatment of the neck and shoulder.

A research review concludes that PBM, both low-intensity laser and LED light, appears to be a safe, effective and non-invasive supplement or alternative to traditional pain-relieving treatments for musculoskeletal complaints.

In summary:

• PBM may affect biological processes involved in pain and inflammation
• PBM may modulate the production of inflammatory signalling molecules
• PBM may reduce oxidative stress and support normal tissue repair processes
• PBM may contribute to reduced pain and better function in some musculoskeletal complaints

Red light therapy has been shown to accelerate the body's natural wound healing process by stimulating the energy production of cells, improving microcirculation and increasing the production of growth factors needed to build new tissue. The light increases the oxygen supply to the wound tissue and promotes the formation of new blood vessels and skin cells, while also reducing inflammation and the risk of infection.

A meta-analysis from 2024 shows that photobiomodulation (PBM), of which red light therapy is a part, gives a 13–38 % greater reduction in wound area and up to 16 times higher likelihood of complete healing compared with standard treatment.

Another meta-analysis from 2025, which included 11 studies with 657 patients with diabetic foot ulcers, found a nearly fivefold chance of complete healing, greater wound contraction and a lower infection rate when PBM was added to standard wound care.

A study of 100 patients showed that 66 % of superficial diabetic foot ulcers were completely closed after 15 days of 660 nm red light, while the control group made minimal progress.

In summary:

• PBM may support biological processes that are important for wound healing
• PBM may modulate inflammation and cellular repair processes
• PBM may promote the formation of new tissue and microcirculation
• PBM may contribute to faster wound healing in some patient groups and studies

Although the results are promising, the clinical evidence varies between different wound types and treatment protocols. More well-controlled studies will help clarify which patient groups benefit most from the treatment.

Preliminary research suggests that red light therapy may have a positive effect on gut health by reducing inflammation and supporting mitochondrial function in the cells of the intestinal lining. Increased mitochondrial activity is thought to support the function of the gut barrier and normal repair processes.

Animal models of ulcerative colitis show that daily irradiation of the abdomen with red LED light reduces damage to the intestinal lining, reduces pro-inflammatory cytokines and preserves tight junctions between cells in the gut lining. Other animal studies report, among other things, lower disease scores and higher levels of the anti-inflammatory signalling molecule IL-10 after light treatment.

A smaller study in humans also showed increased diversity of beneficial gut bacteria after 11 weeks of 904 nm laser treatment over the abdomen, which suggests a light-induced improvement of the gut microbiome. The results are interesting, but need to be confirmed in larger clinical studies.

This review article found that red light therapy has potential as a therapeutic approach for improving gut health by reducing inflammation, strengthening the epithelial barrier and modulating the gut microbiome. However, further research is needed to establish effective treatment protocols and understand the underlying mechanisms.

Photobiomodulation is also being investigated as a possible approach for IBS and other gastrointestinal disorders, but the clinical evidence is currently limited.

In summary:

• PBM may influence biological processes that are important for the function of the gut barrier
• PBM may modulate inflammatory signalling molecules in experimental studies
• PBM may support normal cellular repair processes in the gut lining
• PBM may influence the composition of the gut microbiome in some studies

Although the results are promising, much of the research is currently based on animal studies and smaller clinical studies in humans. More large, well-controlled clinical studies are therefore needed before firm conclusions can be drawn about the effect on various stomach and gut disorders.

Red light therapy has received increased attention in recent years as a natural way to support better, deeper sleep. Unlike blue light from screens and modern lighting, which suppresses the sleep hormone melatonin, research is looking at how
photobiomodulation with red and near-infrared light may affect sleep quality.
Preliminary results suggest that PBM may support biological processes that are
relevant to sleep, rest and recovery.

Research suggests that red and near-infrared light may help to activate the brain's "cleaning system", the glymphatic system, which during deep sleep removes "waste products" that could otherwise build up and be linked to neurological diseases such as Alzheimer's and Parkinson's.

A systematic review and meta-analysis published in 2026 included five randomised, placebo-controlled studies with a total of 240 participants. The pooled analysis showed better perceived sleep quality in participants who received photobiomodulation, compared with placebo treatment.

A small but promising study of patients with mild to moderate Alzheimer's showed that 12 weeks of near-infrared light treatment led to better sleep, reduced restlessness and improved cognitive function, with no side effects.

Although more research is needed, the findings suggest that red light therapy, with regular use, may support both sleep and brain health.

The findings support further research into red and near-infrared light as a possible supplement to good sleep routines. The effect may be influenced by factors such as wavelength, light intensity, treatment area and time of use.

In summary:

With regular use, red light therapy may
have the potential to:

• Contribute to better perceived
  sleep quality
• Support a calmer transition to
  rest
• Be part of a
  relaxing evening routine
• Contribute to increased well-being and a
  feeling of being more rested

Some studies suggest that red light therapy (photobiomodulation) may support the cells' energy production by affecting the mitochondria, the cells' "power plants". The mitochondria produce ATP (adenosine triphosphate), which acts as the cells' main source of energy and is necessary for a wide range of biological processes.

Research suggests that red and near-infrared light may affect mitochondrial function through the absorption of light energy in cellular chromophores, including cytochrome c oxidase, which is part of the electron transport chain. This may contribute to increased mitochondrial activity and ATP production.

Animal studies have shown increased muscle endurance and higher ATP levels after treatment with LED light. An animal study from 2015 showed that red and near-infrared LED therapy increased ATP production in muscle cells and significantly improved physical endurance, with maximum effect about 6 hours after treatment. There was a strong correlation between ATP level and performance, which suggests that the light treatment provides a real energy boost in the cells. Although such results cannot yet be directly transferred to humans, they support the biological mechanism behind the treatment.

By supporting the body's basic energy production, red light therapy may possibly be a tool for supporting health, something also seen in more recent studies on brain health and mitochondrial function.

Benefits of increased cellular energy:

The existing research suggests that photobiomodulation may:

• support the mitochondria's energy production (ATP)
• affect cellular processes that are important for normal cell function
• reduce oxidative stress in some tissues
• contribute to recovery after physical activity in some studies

Red light therapy can stimulate circulation, including microcirculation, by widening the blood vessels and increasing flow in both larger vessels and the smallest capillaries. This happens because the light energy activates nitric oxide, a signalling molecule that makes the blood vessels relax and open up.

In a study, 18 healthy people were exposed to red and near-infrared light on the skin. The researchers wanted to find out whether this could increase the level of nitric oxide (NO). After a short period of light exposure, they could measure a clear increase in NO levels from the skin. This shows that the light directly stimulates the body to release more nitric oxide, without medication or heat, which may explain why red light therapy often leads to better blood circulation and a feeling of warmth in the skin. The study suggests that red and near-infrared light prompts the body itself to release a substance that opens the blood vessels, which improves the flow of blood and nutrients to tissue and muscles.

A review has taken a closer look at how photobiomodulation (PBM), of which red light therapy is a part, actually affects the body's blood vessels. Researchers have identified several mechanisms through which light, especially red and near-infrared, contributes to better circulation. When the body is exposed to certain types of light, the following happens, among other things:

• Nitric oxide (NO) is released from enzymes in the cells (such as cytochrome c oxidase), which makes the blood vessels widen.
• Light also stimulates another enzyme (eNOS) that naturally produces NO in the walls of the blood vessels.

When the blood vessels become stiff or narrow, known as endothelial dysfunction, circulation is reduced. This is common with stress, ageing and certain lifestyle-related conditions, among other things. The study shows that light therapy may reverse this impairment, so that the blood vessels function normally again.

In other words, light treatment can help the body produce and release more nitric oxide (NO), a signalling molecule that makes the blood vessels relax and open up. This gives better blood circulation, and may be particularly useful in cases of poor blood flow or stiff arteries.

The result is better transport of oxygen and nutrients to tissue and organs, while waste products are removed more efficiently. Increased blood circulation therefore gives both faster healing and more energy in the body.

Benefits of better circulation:

• Increased oxygen supply to the cells
• Faster removal of waste products
• Better skin quality and glow
• Less swelling and stiffness

In short: better flow throughout the whole system, for a better-functioning body.

After physical activity, the body needs time and resources to repair and build up the muscles. Photobiomodulation (PBM), of which red light therapy is a part, may support this process. Research suggests that red and near-infrared light can influence biological processes that are important for recovery, including by supporting the energy production of the mitochondria, influencing microcirculation and modulating inflammatory processes.

The light penetrates deep into the tissue and activates the mitochondria, the cells' own "powerhouses", which produce ATP, the energy molecule that drives the function and repair of cells. The result may be faster tissue repair, less soreness and a reduced risk of overload.

Red light therapy may therefore be a valuable tool for both recreational exercisers and athletes who want better recovery and more consistency in their training.

A review of randomised controlled trials (RCTs) on athletes showed that low-level laser therapy (LLLT), a form of red light therapy, may promote faster recovery after exercise. The athletes who received light treatment had lower levels of inflammatory markers such as creatine kinase (CK) and interleukin-6. They also showed better strength and endurance in the days after exercise (24–96 hours).

Another review study showed that PBM used before exercise could improve performance by increasing the number of repetitions and extending the time to exhaustion. Lower levels of biochemical markers of muscle damage were also observed.

In a controlled study with young men, a single LED treatment with red light, given immediately after biceps training, was associated with reduced muscle soreness, loss of strength and restricted movement for up to four days after exercise.

Another study compared LED light therapy with both ice baths and active rest, and reported that the light treatment gave the greatest reduction in creatine kinase, blood lactate and perceived muscle soreness. This suggests that red light therapy may be an effective alternative for recovery.

An extended review of clinical studies in untrained people, recreational exercisers and elite athletes showed that both pre- and post-exercise red light therapy with red or near-infrared light may offer several benefits. Improvements in muscle strength and number of repetitions, reduced inflammation and oxidative stress, lower creatine kinase levels and less perceived muscle soreness were documented.

In summary:

• PBM may support biological processes that are important for muscle recovery
• PBM reduces markers of muscle damage and oxidative stress in some studies
• PBM may contribute to less muscle soreness and faster recovery after physical activity
• PBM may improve muscle performance with certain treatment protocols

There are studies suggesting that red light therapy (photobiomodulation) may influence biological processes that are important for the immune response, including by supporting the energy production of cells, modulating the activity of certain immune cells and influencing inflammatory signalling pathways.

A comprehensive review article published in Lasers in Medical Science in 2025 summarises research suggesting that photobiomodulation may modulate the immune response by influencing macrophages, T cells, dendritic cells and inflammatory signalling pathways, among other things.

Some experimental studies (cell experiments, animal studies, smaller pilot studies on humans) suggest that PBM may influence the activity of immune cells such as monocytes and regulate the production of signalling molecules involved in the immune response.

In animal studies, it has been observed that PBM may influence the balance of signalling molecules that control inflammation (cytokines), and help reduce inflammation. Some studies have suggested that pulsed light may produce different biological responses from continuous light, but this is still an area of ongoing research.

PBM has also been shown to reduce oxidative stress and inflammation in the muscles after physical activity, which may contribute to faster recovery. Since intensive physical strain can temporarily affect the immune response, researchers are also investigating whether PBM may help regulate these processes.

In addition, the treatment may improve microcirculation, which may contribute to better oxygen supply and transport of nutrients to tissue. These biological effects have made photobiomodulation an active field of research within immunology and inflammation. Although the results are promising, the clinical evidence varies between different areas of use.

In summary:

In short, the existing research suggests that photobiomodulation may influence several biological processes linked to immune response and inflammation. Although the results are promising, more large clinical studies are needed to determine the effect in various conditions.

Current research is exploring whether photobiomodulation (PBM) may influence biological processes linked to the body's hormonal regulation. The results are promising in some areas, but the clinical evidence is still limited.

Among other things, researchers are looking at whether PBM may influence biological mechanisms involved in regulating the circadian rhythm and certain hormone systems. There are some indications that PBM affects the circadian rhythm and key hormone-producing glands such as the hypothalamus and the pituitary gland, and may possibly help to improve the balance of levels of, among others, cortisol, melatonin and sex hormones.

By stimulating the mitochondria, the cells' "power plants", production of ATP, the body's main energy molecule, increases. This improves cell function, reduces inflammation and oxidative stress, and may contribute to a more stable hormone balance. In addition, red light supports hormones that regulate collagen production and skin moisture, which may result in firmer, more balanced skin, including during periods of hormonal fluctuation.

Studies suggest that red light therapy may be beneficial for a range of hormonal challenges, particularly in women. The treatment appears to be able to ease symptoms of PMS and menstrual pain, support women with PCOS, and contribute to greater well-being during menopause. Red light therapy may also help with low testosterone levels. This hormone also plays an important role in women, especially after menopause, by influencing energy, muscle strength and libido.

A systematic review of studies in men shows that treatment with red and near-infrared light may have several positive effects on fertility and hormone health. The light treatment appears to be able to improve sperm quality and motility, increase testosterone production and strengthen mitochondrial activity, which together contributes to better cell function and general health.

With regular use, red light therapy, also known as photobiomodulation (PBM), may contribute to better sleep, reduced stress and support hormone balance in connection with PMS, menopause or low energy levels. The effect builds on improved cell function and reduced inflammation, two important factors for hormonal stability.

In summary:

• PBM may influence biological processes that are relevant to hormone regulation
• PBM may support normal cell function through increased mitochondrial activity
• PBM may reduce oxidative stress and modulate inflammatory processes
• PBM may be a promising area of research for certain hormone-related conditions

The clinical evidence is currently limited, and more large, well-controlled studies are needed before firm conclusions can be drawn about the effect on hormone balance and hormone-related conditions.