Light Therapy: A Comparison of Red and Blue Light

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Difference between red and blue light therapy
Frequently Asked

  1. What is the difference between red light and blue light therapy?

    • Red and blue light therapies differ in their wavelengths and therapeutic effects. Blue light (450-495 nm) is on the "short" end of the spectrum and treats conditions that are "skin-deep." Red light, which includes Red LED (600-700 nm), Near-Infrared (700-900 nm), and Infrared (900-1400 nm), penetrates deeper and stimulates changes at the cellular level.

    1. Red vs blue light therapy, which is more effective for:
      • Weight loss? Red light therapy is more effective for weight loss as it causes fat cells to expel lipids, stimulating the body's capacity to burn fat. 
      • Skin health / Deep Wrinkles / Face? Red light therapy is more effective for anti-aging due to its collagen-boosting properties. Blue light therapy is effective for treating acne, eczema, spider veins, and other near-surface skin conditions. Combining both may offer potent therapeutic results. 
      • Acne / Spider Veins? Blue light therapy is effective for treating acne, as it targets bacteria causing acne.
      • Eczema? Blue light therapy is effective for eczema. 
      • Eye issues? Red light therapy is appropriate for treating eye conditions like dry eye syndrome, vitreous floaters, and other diseases. Blue light therapy is not recommended for the eyes. 
      • Reducing cellulite? Both red and blue light can effectively reduce cellulite, but red light therapy can also impact weight loss. 
      • Brain? Blue light therapy can improve alertness and reduce symptoms of SAD.
        Red light therapy improves cognitive function, aids in healing after TBI, and offers benefits for degenerative brain diseases. 
      • Face? Both are used for facial treatments: red light for anti-aging and healing, and blue light for acne.

    2. Can you use both red and blue light therapy on the same day?
      • The data suggests that combining blue and red light might provide potent therapeutic results, implying they can be used together.

      1. What are the specific wavelengths used in red and blue light therapy?
        • Blue light: 450-495 nm, Red LED light: 600-700 nm, Near-Infrared: 700-900 nm, Infrared: 900-1400 nm.

        1. Are there at-home devices available for red and blue light therapy?
          1. When comparing PDT (photodynamic therapy), which is more effective: red or blue light?
            • The provided data does not specifically discuss PDT in relation to red or blue light.

            Light therapy is a relatively new concept in the world of healing. Various forms of light therapy are becoming increasingly popular for treating a wide range of health and appearance concerns.

            But, is all light therapy equal? In a word, no. Wavelengths and their positions on the electromagnetic spectrum make a big difference in their therapeutic effects for any given purpose.

            The two most prevalent forms of at-home light therapy today are blue and red.
            In this article, we will compare the efficacy of blue and red light as it applies to several common therapeutic uses. 

            Table of Contents

            An Overview of the Properties of Blue and Red Light Wavelengths

            Blue Light Therapy

            Blue light resides on the visible range of the electromagnetic spectrum, with wavelengths measuring approximately 450 to 495 nanometers (nm).
            Because blue light wavelengths are on the “short” end of the spectrum, they can only penetrate your body to a shallow level, just beneath your skin. Since light therapy can only treat conditions that it can reach, blue light is effective only in treating conditions that are “skin-deep”.
            Blue light is part of our everyday lives. Commonly used electronics and home lighting sources emit blue light; we encounter it regularly. In fact, we experience so much of it that it can cause adverse side effects if our exposure to it is not mitigated. Blue-blocking glasses serve this purpose.
            Negative effects from overexposure to blue light include sleep disturbances, headaches, concentration problems, decreased attention span, and a feeling of malaise.
            Blue light, however, is not always bad. While we need to be cautious about overexposure to blue light, it also provides benefits that we will explore later in this article.

            Red Light Therapy

            Red light is longer in wavelength than blue, and consists of three types:

            Red Light-Emitting Diode (LED)

            Red LED light is the shortest type of red light; however, all red light is on the “long” end of the spectrum. Red LED light ranges in wavelength from approximately 600 to 700 nm, is visible, and penetrates to about eight to 10 millimeters (mm) beneath your skin. Red LED light is commonly utilized as an at-home therapy option.

            Near-Infrared (NIR) 

            NIR light wavelengths measure about 700 to 900 nm. NIR light is visible; however, because it borders on infrared light, it may become invisible at wavelengths near the top of its range. It penetrates to a depth of about 1.25 to 2 centimeters (cm). NIR light is also commonly utilized in at-home red light therapy, frequently in conjunction with red LED light.


            The longest form of red light, infrared is invisible. Infrared wavelengths range from about 900 to 1400 nm. Unlike red LED and NIR light, infrared light is thermal, which means it produces heat and is capable of burning your skin. It penetrates your body to a level of around 2.5 centimeters (cm).

            There are some treatment uses for infrared light; however, due to its potential safety risks, at-home red light therapy is typically administered in the forms of red LED and NIR light. It is important to note that the blue and red wavelength ranges are approximate. This is because the spectrum is continuous and there is no fixed beginning or ending point for any “color” of light. Like looking at a rainbow, the colors blend.

            The wavelength ranges specified here are generally accepted approximations of each light form, but they are not hard and fast. This is why NIR light is visible at the short end of its range but approaches invisibility at the top of its range.
            As opposed to blue light, red light stimulates your body to change at its cellular level due to its propensity to penetrate more deeply. 

            Side by Side Comparisons by Treatment Use: Which Works Better, Blue or Red Light Therapy?

            Given their different properties, which works best for which applications – red or blue light? Now we will delve into some common uses of light therapy and discuss the pros and cons of red versus blue light for each.

            Skin Health


            The appearance of wrinkles and fine lines, crepey eyelids, and saggy skin are all common signs of aging. Your skin’s elasticity is maintained primarily by collagen, an essential structural protein. Collagen is the most plentiful protein in your body, making up about one-third of your total protein content and about 75 percent of your skin’s protein content. Red light therapy stimulates your body’s cellular energy, boosting your natural collagen production and restoring your skin to a smoother, firmer, more youthful appearance. [1] Blue light’s shorter wavelengths do not activate this biochemical process.


            Red light therapy is more effective than blue for anti-aging purposes.

            Acne, Sun Damage, Eczema, Psoriasis, Rosacea, and Other Skin Conditions

            Because most acne is caused by bacteria residing directly under the skin and clogging hair follicles, blue light therapy is effective for acne treatment and prevention. [2] [3] [4]

            Blue light is also effective at treating skin conditions such as psoriasis [5] (caused by an overproduction of skin cells) and eczema [6] [7] (characterized by itchy, rough, red, and inflamed skin). This is because such conditions have root causes directly beneath the skin.

            Blue light can help with any condition that resides or has a root cause on your skin’s surface or directly beneath it. Spider veins, varicose veins, and sun damage are other examples.

            While studies prove the efficacy of blue light in treating acne and other skin conditions, other studies also prove the effectiveness of red light therapy as a stand-alone treatment. [8] [9]

            One study, in particular, demonstrates that blue and red light are more effective when used conjunctively. This study treated patients with a combination of 415 nm (blue), 633 nm (red LED), and 830 nm (NIR) light and reported better results than with either blue or red light alone. [10]


            Blue light is a highly effective treatment for acne, eczema, spider veins, and other near-surface skin conditions. Red light, however, has also been proven effective for the same uses. Either can be used, but a combination of blue and red light might provide the most potent therapeutic results.


            The type of light best suited to treating scars depends upon the type of scar. Surface scars that are superficial in nature (such as stretch marks, mild acne scars, and fine line scars) can derive some benefit from blue light therapy. Thicker, deeper scars will require red light therapy to heal.

            All scars, however, will likely benefit more from red light therapy. Because red light therapy increases cellular energy, its restorative and rejuvenating capabilities are greater than those of blue light. [11]

            Red light offers another treatment element that blue light lacks: the activation of stem cell production. [12] Stem cells are “cellular building blocks” that can divide and produce new cells with specialized purposes as needed. Cells located close to each other tend to take on one another’s characteristics. New stem cells at a skin injury/scar site prompt the damaged cells to take on the properties of healthy skin cells, thus aiding the scar healing process.

            While blue light can have some effect on mild, superficial scarring, red light therapy provides better overall skin restoration and scar healing.  

            Eye Health and Conditions

            Eye conditions like dry eye syndrome and vitreous floaters can be treated with red light therapy. Because red light therapy enhances hydration, dry eyes can be relieved. Vitreous floaters occur when bits of collagen detach from the retina of your eye. Because red light therapy increases collagen production and quality, the occurrence of floaters is reduced.

            Blue light, conversely, is thought to be one of the potential causes of dry eyes. Prolonged “screen time” in front of a television or computer can cause your eyes to lose lubrication and become irritated.

            Cellular and mitochondrial functions factor into most eye diseases. For this reason, the following eye diseases can benefit from red light therapy:

            • Glaucoma
            • Macular Degeneration
            • Retinitis Pigmentosa
            • Amblyopia (Lazy Eye)
            • Cataracts

            The blue light used in therapy is typically more intense than that which is emitted from electronic devices. Blue light therapy is useful for skin treatment but not eye treatment. Blue light can damage your optic nerve, harm the lens of your eye, cause corneal or retinal damage, and even damage your DNA. Eye protection from blue light is recommended.


            Red light therapy is appropriate and effective for treating eye conditions and diseases. Blue light therapy is not safe or recommended for this purpose.  

            Weight and Cellulite Concerns

            For purposes of comparing red and blue light therapy, weight loss and cellulite reduction must be considered separately.

            Weight Loss

            Red light causes fat cells to expel lipids, effectively burning fat. Your body’s capacity to kill fat cells is stimulated and your metabolic rate is heightened. You burn more calories naturally. [13] Blue light therapy does not cause cellular change; thus, it has no impact on weight loss.

            Cellulite Reduction

            Cellulite is fat stored immediately beneath your skin and typically has a dimpled, cottage-cheese-like appearance. Because it is so close to your skin’s surface, blue light can effectively reduce cellulite. This, however, is a more superficial effect than the power of red light to burn fat more efficiently by activating natural cellular processes.


            Both red and blue light can effectively reduce cellulite. Red light therapy can have a profound effect on weight loss, but blue light cannot.

            Pain Management

            Because red light therapy stimulates better circulation, reduces inflammation (a leading cause of many types of pain), and activates the production of new, healthy stem cells, pain relief is achieved.

            Red light therapy can relieve acute pain, neuropathic pain, and chronic pain resulting from conditions such as fibromyalgia [14], osteoarthritis [15], and back injury.

            Blue light therapy cannot penetrate deeply enough to cause any of these biochemical reactions; thus, it is not an effective form of pain management.


            Red light therapy beats blue light for pain management and relief.

            Wound and Injury Healing

            The stem cell proliferation resulting from red light therapy sends damaged cells at an injury site the message to adapt to the properties of healthy cells. This reduces the likelihood of infection and promotes faster recovery. Even bone marrow stem cells are affected, giving rise to the deepest level of healing. [16]

            Blue light therapy can have some effect on superficial wounds; however, for deep tissue healing, red light therapy is the more effective option. [17]


            Other than surface injuries, the greatest healing potential comes from red light therapy as opposed to blue.


            Sleep patterns are tied to your “circadian rhythm”; the internal biological clock that determines when your body naturally wants to sleep and wake. Blue light is known to disrupt your circadian rhythm because it stimulates your brain rather than relaxing it. Melatonin production is suppressed, causing wakefulness. [18]

            Red light, on the other hand, soothes and calms your mind and body and supplements your natural circadian rhythm, promoting healthy sleep patterns.


            Red light therapy helps to maintain a peaceful, regular sleep pattern.

            Brain Health

            Overall brain health encompasses an array of issues from cognitive function, ability to concentrate, depression and anxiety, seasonal affective disorder (SAD), traumatic brain injury (TBI), and even dementia and degenerative diseases like Alzheimer’s and Parkinson’s.

            Because blue light is known to help your brain stay awake and alert, it can help you focus and increase your attention span during the day. Cognitive function is heightened when it needs to be. [21] Before bed, however, blue light will continue to have these effects and distress your sleep patterns.

            Light therapy is a common treatment for depression, anxiety, and conditions like SAD. Blue light therapy, because of its ability to “wake up” and energize your brain, is proven to reduce fatigue and relieve symptoms of depression and SAD when used properly. [22] [23] [24]

            Concerning TBI and degenerative brain conditions, blue light therapy is not effective because it cannot penetrate to the level necessary to effect change. Red light therapy, however, can help. Increased cerebral blood flow is induced by red light therapy, thus reducing inflammation, revitalizing the production of stem cells, and affecting metabolic cell function. Neurogenesis (growth of new neurons within your brain) is stimulated. [25]

            Neurogenesis and the other results of red light therapy improve cognitive function, accelerate healing after TBI, and provide benefits for degenerative brain disease and dementia. Because your brain is functioning at a higher level with regard to forming neural connections, symptoms of brain degeneration are slowed and lessened. Problem-solving skills and overall mental acuity are heightened. [26] [27]


            Blue light therapy is effective for mood elevation, relieving fatigue, reducing daytime sleepiness, increasing alertness, and relieving SAD. For long-term concentration improvement, cognitive function, and the treatment of degenerative diseases such as Alzheimer’s and Parkinson’s, red light therapy is more effective.

            Physical Fitness, Athletic Performance, Muscle-Building, and Post-Workout Recovery

            The increased cellular energy and ATP provided by red light therapy boost your overall bodily energy. This leads to increased stamina, strength, and endurance, allowing you to perform at your optimal athletic level. [19] Muscle growth is another natural result.

            Better circulation and oxygenation allow you to work out harder while experiencing less exhaustion and tissue injury, thus leading to faster post-workout recovery times [20].

            Because blue light only works near the surface of your body, none of these biochemical changes are triggered. Deep tissue is not affected.


            Only red light therapy, not blue, is effective for building muscle mass, helping you reach your peak physical fitness and athletic performance levels, and allowing for quicker recovery after exercise.  

            Testosterone and Fertility

            Red light therapy has been shown to boost testosterone production in men and improve fertility. Testosterone is produced in the Leydig cells present in a man’s testicles. Because of the increased cellular energy produced by red light therapy, Leydig cells are prompted to elevate the level of testosterone production.

            Fertility is improved because ATP production stimulates greater sperm production and better sperm motility.

            Blue light has the opposite effect on testosterone and fertility. Blue light decreases cellular energy rather than increasing it. It inhibits ATP production, which is the opposite of what is needed for more testosterone production and better sperm quality. While these attributes can make blue light effective at killing bacteria and reducing acne, they are detrimental to the fertility process.


            Red light therapy is effective for boosting testosterone and fertility, but blue light therapy is not.  

            What Types of At-Home Devices Are Available for Blue and Red Light Therapy?

            Blue light therapy is mainly available in the form of wands, pens, and face masks. The wands or pens target very specific areas and can be used not only on your face, but elsewhere on your body to treat acne or other skin conditions, spider veins, and varicose veins.

            A broader range of red light therapy devices is available for at-home use. Similar pens, wands, hand-held devices, and masks come in a variety of singular wavelength or wavelength combination options. Panels in many sizes are also available since red light is more appropriate for less targeted, more generalized usage. Table-top panels, as well as full-body panels, offer additional treatment options to suit your personal needs.

            All devices offer light therapy that is easily and conveniently administered at home, on your own timetable.

            Whatever your specific treatment needs, light therapy is a revolutionary and safe new method of alleviating an array of health and appearance concerns. Red light therapy at home in particular offers this healing potential by tapping into your body’s natural, biochemical processes and stimulating cellular change.  


            [1] A Controlled Trial to Determine the Efficacy of Red and Near-Infrared Light Treatment in Patient Satisfaction, Reduction of Fine Lines, Wrinkles, Skin Roughness, and Intradermal Collagen Density Increase (opens in a new tab)
            [2] Acne phototherapy with a high-intensity, enhanced, narrow-band, blue light source: an open study and in vitro investigation (opens in a new tab)
            [3] 420 nm intense continuous light therapy for acne (opens in a new tab)
            [4] A new targeted blue light phototherapy for the treatment of acne (opens in a new tab)
            [5] Efficacy of blue light vs. red light in the treatment of psoriasis: a double-blind, randomized comparative study (opens in a new tab)
            [6] Clinical efficacy of blue light full body irradiation as a treatment option for severe atopic dermatitis (opens in a new tab)
            [7] Prospective, Randomized Study on the Efficacy and Safety of Local UV-Free Blue Light Treatment of Eczema (opens in a new tab)
            [8] Red light phototherapy alone is effective for acne vulgaris: randomized, single-blinded clinical trial (opens in a new tab)
            [9] A clinical review of phototherapy for psoriasis (opens in a new tab)
            [10] Low-level laser (light) therapy (LLLT) in skin: stimulating, healing, restoring (opens in a new tab)
            [11] High-Fluence Light-Emitting Diode-Generated Red Light Modulates the Transforming (opens in a new tab)
            Growth Factor-Beta Pathway in Human Skin Fibroblasts (opens in a new tab)
            [12] Effects of low-level red-light irradiation on the proliferation of mesenchymal stem cells derived from rat bone marrow (opens in a new tab)
            [13] Low-level laser therapy for fat layer reduction: a comprehensive review (opens in a new tab)
            [14] Low-Level Laser Therapy for Fibromyalgia: A Systematic Review and Meta-Analysis (opens in a new tab)
            [15] The clinical efficacy of low-power laser therapy on pain and function in cervical osteoarthritis (opens in a new tab)
            [16] Effects of low-power light therapy on wound healing: LASER x LED (opens in a new tab)
            [17] Light therapy by blue LED improves wound healing in an excision model in rats (opens in a new tab)
            [18] Blue light has a dark side (opens in a new tab)
            [19] Improvement of Performance and Reduction of Fatigue With Low-Level Laser Therapy in Competitive Cyclists (opens in a new tab)
            [20] Photobiomodulation Therapy Improves Performance and Accelerates Recovery of High-Level Rugby Players in Field Test: A Randomized, Crossover, Double-Blind, Placebo-Controlled Clinical Study (opens in a new tab)
            [21] Effects of artificial dawn and morning blue light on daytime cognitive performance, well-being, cortisol and melatonin levels (opens in a new tab)
            [22] Randomized controlled trial of light therapy for fatigue following traumatic brain injury (opens in a new tab)
            [23] Light therapy for seasonal affective disorder with blue narrow-band light-emitting diodes (LEDs) (opens in a new tab)
            [24] Tailored lighting intervention improves measures of sleep, depression, and agitation in persons with Alzheimer’s disease and related dementia living in long-term care facilities (opens in a new tab)
            [25] Shining light on the head: Photobiomodulation for brain disorders (opens in a new tab)
            [26] Treating cognitive impairment with transcranial low-level laser therapy (opens in a new tab)
            [27] Transcranial low-level laser therapy improves brain mitochondrial function and cognitive impairment in D-galactose-induced aging mice (opens in a new tab)
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            1 comment

            Excellent comparisons. I own a red light/infrared device and am amazed by the improvements I have experienced. Thank you for so thoroughly delineating the differences and benefits, between blue and red light therapy. Outstanding assessment and post!

            Taffy Rice
            Thank you Taffy! I appreciate you taking the time to appreciate this post and chuffed to hear that you're experienced improvements through red light therapy.
            RLT Home Admin September 21, 2023

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