Light Therapy FAQs
Questions about light therapy?
Keep reading for answers to the most frequently asked questions about light treatments. We’ll cover everything on your mind about red light therapy, blue light therapy, light therapy at home, and the benefits of light therapy.
Q: What is red light therapy?
A: Red light therapy devices shine specific wavelengths of red and sometimes near infrared (NIR) light on the body to produce positive biological effects. Red light therapy is widely used for skin health benefits and for treating skin conditions like cold sores, acne, mouth sores, and genital sores.
Red light therapy is also popular for muscle recovery treatments after workouts, and for helping heal injuries and wounds. Red light therapy has been tested in thousands of peer-reviewed clinical trials, with overwhelmingly positive results for efficacy and safety.
Q: How does light therapy work? Why does the body respond to light therapy?
A: In short, light therapy works by improving cellular function. Every living thing needs light to produce energy and power itself. The mitochondria in our cells absorb wavelengths of light from the sun and use it to make energy and power the body with adenosine triphosphate (ATP). [1,2]
Light therapy treatments supplement natural sunlight with concentrated wavelengths of light. When your cells consistently get an abundance of this kind of natural light, your body performs better.
Light therapy treatments with red wavelengths have been shown to enhance blood circulation, reduce pain, and help the body process inflammation. [3,4] This leads to widespread health benefits, like better skin, improved sleep, more energy, faster healing, and stronger performance.
Q: What does red light therapy do?
A: Light therapy devices deliver concentrated wavelengths of light to the body and cells. When your cells take in an abundance of light, they’re able to produce energy more efficiently. Red light therapy has been shown to reduce inflammation and improve blood flow, which leads to numerous skin and healing benefits, as well as better muscle recovery and sleep. It can even improve hair growth.
Q: What are the benefits of red light therapy?
A: Light therapy improves cellular health and energy production, and has an anti-inflammatory effect on the body. With consistent usage, these are among the most commonly reported benefits of light therapy:
- Improved skin
- Quicker healing of cold sores and genital sores
- Improved healing of acne, wounds, and burns
- Better sleep
- Enhanced muscle recovery
- Stronger physical performance
- Hair growth
- Fewer SAD symptoms
Q: How often should I use red light therapy?
A: For the best results, use light therapy every day, or at least five times per week. Consistency is crucial for effective light therapy. The more regularly you use light therapy, the better your results will be.
For people treating skin conditions, do two to three short light therapy sessions per day as soon as you feel symptoms emerging. Check out this article for more details on how often you should use light therapy.
Q: How should I use light therapy?
A: With an LED device, you can use light therapy at home. It’s best to be consistent with your treatments and do them every day or at least five times per week.
The type of device you should buy depends on which type of health benefits you’re looking for. If you want to treat a specific skin condition like cold sores or acne, look for a handheld device that targets skin blemishes. If you want to improve hair growth, numerous companies make low-level laser helmets and combs. If you want general light therapy benefits, like improved energy production, you can purchase a larger device that uses panels of LEDs to deliver light across the body.
Q: How do I use red light therapy at home?
A: Light therapy is a quick and simple treatment you can use in the comfort of your home. Numerous light therapy brands sell LED panels or handheld devices designed for regular personal use at home. At-home light therapy treatments are more effective and affordable than going to a doctor or spa, allowing you to be more consistent in your treatments after the one-time cost of purchasing the device.
Q: What is blue light therapy?
A: Blue light therapy uses wavelengths of blue light in the 450 to 490 nanometer range. Blue light therapy treatments are primarily used to treat acne, with many brands selling personal blue light therapy masks and wands.
Q: How long does it take for light therapy to work?
A: Everyone’s body is different. Many people using light therapy experience acute benefits, like a boost in energy, focus, or mood. People treating skin conditions like cold sores may see improvements within a few days. For longer-lasting benefits like reduced inflammation, improved skin health, or better sleep, it usually takes a few weeks of consistent light therapy sessions to see results.
Q: What is light therapy for skin?
A: Light therapy is a popular skin and beauty treatment among dermatologists and estheticians. Blue light therapy is mostly used for acne treatments. Red and NIR light treatments are used to improve complexion and treat skin conditions like cold sores, canker sores, acne, wounds, burns, and genital herpes.
Q: Is light therapy supported by clinical research?
A: Yes, light therapy is backed by science and research. Light therapy, especially red light therapy, is widely researched and studied around the world for its clinical applications. Light treatments are supported by over 2,000 peer-reviewed clinical studies, and more research is always emerging. The data has shown that light therapy is well-tolerated by patients of all ages, and almost completely free of side effects and complications. [5,6]
Q: When did light therapy start? How long has light therapy been a treatment?
A: Light therapy has been used in medicine since the beginning of the 1900s. NASA experimented with red light therapy use in space in the 1980s and 1990s.  Since the 1990s, a proliferation of clinical research on the benefits of light therapy has led to more widespread use of light treatments in clinical settings. But light therapy has really taken off with the public in the last 5-10 years, as advances in LED technology have led to easy, affordable use of at-home light therapy devices.
Q: Can you treat cold sores with light therapy?
A: Yes, light therapy can treat cold sores. Numerous peer-reviewed clinical trials have shown light therapy treatments can improve healing results and limit outbreaks of herpes labialis.
One example of a light therapy device designed to treat cold sores is the Luminance RED Cold Sore Treatment Device. Check out this post to read more about light therapy and cold sores.
Q: Can you treat canker sores with light therapy?
A: Yes, light therapy treatments can treat canker sore outbreaks. More than 25 clinical studies have demonstrated that light therapy significantly reduces pain from canker sores, speeds the healing time of canker sores, and can make eating, drinking, and functioning normally easier during a severe canker sore outbreak.
One example of a light therapy device designed for canker sore treatments is the Luminance RED Mouth Sore Treatment Device. Read more about light therapy and canker sores here.
Q: Can light therapy help with wounds and burns?
A: Yes, light therapy is used in clinical settings to help patients heal from burns, wounds, and surgical incisions. Researchers in a 2018 review determined that light therapy with red wavelengths significantly increased tensile strength and wound contraction, leading to faster, more effective wound healing results across the body. 
One example of a light therapy device designed to improve the healing of canker sores is the Luminance RED Mouth Sore Treatment Device.
Q: Does light therapy work for genital herpes?
A: Yes, light therapy can treat and prevent genital herpes outbreaks. Clinical research indicates that light treatments may lessen the viral load of HSV-2 present in the body. 
One example of a light therapy device designed for genital herpes is the Luminance RED Genital Sore Treatment Device. Read this article to learn more details about light therapy as a genital herpes treatment.
Q: Does red light therapy reduce inflammation?
A: Inflammation relief is one of the major benefits of light therapy. Light treatments with red wavelengths have an anti-inflammatory effect, as shown in clinical trials.
Dr. Michael Hamblin of Harvard Medical School is a leading light therapy researcher who has demonstrated in numerous trials how wavelengths of red and NIR light has a significant effect on reducing inflammation. He has shown “an overall reduction in inflammation, which is particularly important for disorders of joints, traumatic injuries, lung disorders and in the brain.” 
Q: Does light therapy help with hair loss? Does light therapy help grow hair?
A: A growing base of clinical research is demonstrating that light therapy treatments with red wavelengths can stimulate hair growth, improve hair thickness, and help prevent hair loss from male and female pattern baldness. [10,11,12]
Red light therapy has also been shown to have a major stimulating effect on the dermal papilla cells, which play a big role in the regulation of hair cycling and growth.  Numerous light therapy products are sold specifically to prevent hair loss and to stimulate hair regrowth.
Q: Does light therapy help you sleep?
A: Many people struggle to sleep because they don’t get enough natural light during the day and overload their eyes and brains with bright, artificial blue light from screens at night. This throws off hormone production and the sleep cycle, and can lead to sleep disorders like insomnia.
Clinical research is showing that exposure to red light therapy can improve sleep quality and duration, and also help people produce more of their own melatonin.  Red light has a much lower color temperature than blue light or sunlight, so it’s a good choice for winding down in the evenings and transitioning into restful sleep. 
Q: Which colors are best for light therapy?
A: Red and NIR light are the most common wavelengths of light used for light therapy sessions. Red light in the 620-750 nanometer range is the most studied and tested, with over 1,000 clinical studies showing significant positive results with few risks or side effects.
Blue light therapy is primarily used in acne treatments. Green light therapy has shown early promise in select studies on migraines. Yellow light and orange light have not been widely used or studied for light therapy treatments. [16,17,18,19,20]
Learn more about the different colors and wavelengths of light therapy on this page.
Q: What are the best red light wavelengths?
A: Red light in the 620 to 750 nanometer range has shown the best results for light therapy treatments. Most consumer devices offering red light therapy use light within this range on the electromagnetic spectrum.
Q: Is light therapy safe?
A: Yes, light therapy has been tested and analyzed in thousands of peer-reviewed trials. The consensus among medical researchers and the clinical community is that natural light treatments are safe, well-tolerated, and produce little to no side effects. Research teams have concluded this in study after study. Dermatology researchers from Harvard Medical School conducted a review of red light therapy in 2013 and praised its “noninvasive nature and almost complete absence of side effects.” 
Q: What are other names for light therapy?
A: Light therapy is also called phototherapy, photobiomodulation (PBM), red light therapy (RLT), and LED therapy.
Q: What’s the difference between light therapy and infrared saunas?
A: Light therapy is different from infrared saunas and traditional saunas in that it doesn’t use heat to produce a biological response.
Q: Does light therapy have UV rays?
A: No, light therapy treatments do not contain UV rays like sunlight does.
Sources and References:
 Karu T. Primary and Secondary Mechanisms of Action of Visible to Near-IR Radiation on Cells. Journal of Photochemistry Photobiology. 1999 Mar.
 Ferraresi C, Kaippert B, et al. Low-level Laser (Light) Therapy Increases Mitochondrial Membrane Potential and ATP Synthesis in C2C12 Myotubes with a Peak Response at 3-6 h. Photochemistry and Photobiology. 2015 Mar.
 Hamblin M. “Mechanisms and applications of the anti-inflammatory effects of photobiomodulation.” AIMS Biophys. 2017.
 Huang YY, Chen ACH, Carroll JD, Hamblin MR. Biphasic dose response in low level light therapy. Dose Response. 2009 Sep.
 Avci P, Gupta A, et al. Low-level laser (light) therapy (LLLT) in skin: stimulating, healing, restoring. Seminars in Cutaneous Medicine and Surgery. Mar 2013; 32(1): 41-52.
 Healthline. Light Therapy for Acne, What to Expect.
 NASA. LED Lights Used in Plant Growth Experiments for Deep Space Missions.
 Gál P, Stausholm MB, et al. Should open excisions and sutured incisions be treated differently? A review and meta-analysis of animal wound models following low-level laser therapy. Lasers in Medical Science. 2018 Aug.
 Waked, Deghidi, and Shalaan. HONEY PHONOPHORESIS VERSUS LOW INTENSITY LASER THERAPY IN FEMALE GENITAL HERPES. IJCRR, Vol. 6, Issue 10. May 2014.
 Liu KH, Liu D, et al. “Comparative effectiveness of low-level laser therapy for adult androgenic alopecia: a system review and meta-analysis of randomized controlled trials.” Lasers in Medical Science. 2019 Aug.
 Gupta AK, Mays RR, et al. “Efficacy of non-surgical treatments for androgenetic alopecia: a systematic review and network meta-analysis.” JEADV. 2018 Dec.
 Afifi L, Maranda EL, et al. “Low-level laser therapy as a treatment for androgenetic alopecia.” Lasers in Surgery and Medicine. 2017 Jan.
 Joo HJ, Jeong KH, et al. Various Wavelengths of Light-Emitting Diode Light Regulate the Proliferation of Human Dermal Papilla Cells and Hair Follicles via Wnt/β-Catenin and the Extracellular Signal-Regulated Kinase Pathways. Annals of Dermatology. 2017 Dec.
 Morita T., Tokura H. “Effects of lights of different color temperature on the nocturnal changes in core temperature and melatonin in humans.” Journal of Physiological Anthropology. 1996 September.
 Lirong Z., Phyllis Z. “Circadian Rhythm Sleep Disorders.” Neurologic Clinics. 2012 November.
 Lynch, David K.; Livingston, William Charles (2001). Color and Light in Nature (2nd ed.). Cambridge: Cambridge University Press. p. 231. ISBN 978-0-521-77504-5.
 Elert, Glenn. “The Electromagnetic Spectrum, The Physics Hypertextbook.” Hypertextbook.com.
 Kumar, Narinder. 2008. Comprehensive Physics XII. Laxmi Publications.
 Laufer, Gabriel. 1996. Introduction to Optics and Lasers in Engineering.
 Healthline. Green Light for Migraines: Does This Therapy Work?