Red Light Therapy for Horses: Science, Benefits & How It Works
Red light therapy, also known as photobiomodulation (PBM), uses specific wavelengths of red and near-infrared light to interact with biological tissue. Research has explored PBM across different wavelengths, irradiances and doses, with outcomes influenced by factors including wavelength, light intensity, treatment time, target tissue and biological models.
Explore Wavelength Science and Usage & Applications pages.
At a Glance
What it is
Red and near-infrared light used in photobiomodulation and how it interacts with biological tissue.
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The Science
How wavelength, irradiance, dose and session time influence light delivery and biological response.
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The Wavelengths
A closer look at 660nm, 850nm and 940nm and why different wavelengths behave differenty in tissue.
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The Equine Factor
How coat, hair, skin characteristics and session location can affect light transmission in horses.
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The Evidence
What research tells us about PBM - including equine research and relevant laboratory and preclinical studies.
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Practical Use
Key considerations for treatment areas, session duration, frequency and consistent application.
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Choosing a System
What to look for when evaluating an equine light system beyond LED count or marketing claims.
What Is Red Light Therapy for Horses?
For horses, PBM is used as a non-invasive supportive modality within a broader program of veterinary care, training, farrier care, rehabilitation and everyday management.
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The way light is delivered matters. A horse's coat, hair length, skin characteristics, pigmentation, tissue thickness and treatment area can all influence how much light reaches the underlying tissue. Equine research has demonstrated measurable light transmission to both superficial and deeper structures, while also showing that factors such as clipping and tissue characteristics affect transmission.
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This is why an equine light system should be evaluated by more than its LED count or advertised wavelength. The design, wavelength, irradiance, coverage, treatement time and delivered dose all matter when considering how light is applied to the horse.
How Red Light Therapy Works in Horses
When red or near-infrared light reaches tissue, photons must be absorbed by molecules within the tissue before they can produce a biological response. These light-absorbing molecules are called chromophores. One of the principal proposed targets of red and near-infrared PBM is cytochrome c oxidase, an enzyme located within the mitochondria. (Pubmed Central (PMC)
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Mitochondria are responsible for producing much of a cell's useable energy in the form of ATP. Research suggests that PBM can influence mitochondrial activity and cellular signaling, including changes in ATP production, reactive oxygen species and other downstream pathways. These responses are influenced by the light parameters used, including wavelength and dose. (Pubmed Central Articles)
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This is why red light therapy is not simply a matter of shining light on the horse. All the above factors contribute to the biological response. Importantly, the response can vary with dose and biological context; more light is not necessarily better.
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Does Red Light Therapy Work for Horses?
Research suggests that PBM is an excellent non-invasive modality with significant effect on tissue response, circulation, musculoskeletal function, pain and recovery.
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Research in horses and other biological models continues to expand our understanding of how PBM can influence cellular and tissue responses. Equine research has also demonstrated measurable light transmission to both superficial and deeper structures, providing important insight into how red and near-infrared light can interact with equine tissue.
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At ReGen Equine, we focus on applying the science to our systems
What does the Research show?
Research into photobiomodulation continues to expand across equine, veterinary and laboratory settings. Studies have investigated how red and near-infrared light can influence cellular activity, tissue response and functional outcomes, with growing interest in how specific wavelengths and treatment parameters can be applied to different tissues.
Equine research provides particularly useful insight into light delivery through the horse. Studies have measured light transmission through equine skin and into the superficial and deep digital flexor tendons, demonstrating that measurable energy can reach deeper structures and that factors such as coat, skin pigmentation, skin thickness and clipping can influence transmission. (PubMed Transmission)
Research outside the horse also helps us understand wavelength-specific biological responses. A 2025 study comparing 625, 810, 940 and 1050 nm found particularly strong cartilage-related responses under the tested 940 nm / 52 J/cm² condition in both chondrocyte and mouse knee osteoarthritis models. (MedChemExpress)
Together, this body of research helps inform how photobiomodulation can be thoughtfully applied to equine systems—and why ReGen continues to look beyond a wavelength label alone when evaluating light technology.
How Does Hair Affect Red Light Therapy in Horses?
A horse’s coat is an important consideration when applying light-based technology. Hair, skin pigmentation and skin thickness can influence how much light is transmitted through the surface and reaches the underlying tissue.
Equine research comparing 800 nm and 970 nm light found that hair color, skin color, skin thickness and whether the hair was clipped or shaved all affected light transmission. The study also measured energy reaching both the superficial digital flexor tendon and deep digital flexor tendon. Ex. vivo penetration of low-level laser through equine skin and flexor tendons
This research highlights an important consideration for equine light systems: delivering light through a horse’s coat requires more than simply selecting a wavelength. System design, output and practical contact with the treatment area all contribute to how light is delivered.
For horses with a dense or longer coat, consistent application and close contact with the treatment area can help maximize the amount of light available to the tissue beneath the coat.
How Deep Does Red Light Therapy Penetrate?
Red and near-infrared light can travel beyond the surface of the skin, but the amount of light reaching deeper tissue depends on the wavelength and the optical properties of the tissue it passes through. Light is progressively scattered, reflected and absorbed as it travels, so the energy available at the target tissue is always less than the energy delivered at the surface.
The near-infrared range is particularly important for applications involving deeper tissue. Research has demonstrated that wavelengths in this range can transmit through biological tissue, while penetration characteristics vary between wavelengths and tissue types.
For ReGen Equine, this is one reason our Tri-Wave Light System™ combines three wavelengths rather than relying on a single wavelength:
660nm — red light used primarily for more superficial tissue interaction.
850nm — near-infrared light commonly used when targeting deeper soft tissue.
940nm — a longer near-infrared wavelength that interacts differently with tissue and is included to broaden the range of light delivered across tissue layers.
Importantly, “penetration” does not mean that every photon travels to a specific depth or that a particular wavelength automatically reaches a joint, tendon or other structure. What matters is how much usable light reaches the target tissue under the actual treatment conditions.
This is also why equine light delivery cannot be evaluated by wavelength alone. The horse’s coat, skin, tissue characteristics, treatment area and the output of the light source all influence how much energy is available beyond the surface.
For a deeper look at how 660nm, 850nm and 940nm differ—and the research behind our Tri-Wave approach, explore Wavelength Science.
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What Wavelength is Best For Horses?
There is no single wavelength that is best for every equine application. Different wavelengths interact with tissue differently, which is why red and near-infrared wavelengths are often used together in photobiomodulation.
660nm red light is generally associated with more superficial tissue interaction, while 850nm near-infrared is commonly used when targeting deeper soft-tissue structures. 940nm adds another near-infrared wavelength with its own optical and biological characteristics, allowing a broader range of near-infrared light to be delivered rather than relying on one wavelength alone.
For this reason, ReGen Equine uses a Tri-Wave Light System™ combining 660nm + 850nm + 940nm. The goal is not simply to include more wavelengths, but to provide complementary wavelengths across different tissue depths and applications.
The science behind each wavelength—and why ReGen combines all three—is explored in greater detail in our Wavelength Science guide.
How Long Should You Use Red Light Therapy on a Horse?
The frequency of red light therapy can vary depending on the horse, the area being treated, the purpose of the application and the light system being used. Photobiomodulation is generally most useful when incorporated into a consistent care routine rather than viewed as a one-time application.
For routine use, sessions can be incorporated around training, exercise, competition and ongoing maintenance. A consistent schedule allows owners to monitor how their horse responds and adjust the routine as needed.
More frequent application is not automatically better. The goal is to provide an appropriate amount of light for the intended application and allow the horse’s tissues time to respond between sessions.
For specific ReGen application guidance, including recommended session schedules and treatment areas, see our Usage & Applications guide.
Can Red Light therapy Be Used Every Day on a Horse?
Red light therapy can be incorporated into a horse’s regular care routine, including on consecutive days when appropriate for the application and the light system being used.
Red light therapy can be incorporated into a horse’s regular care routine, including on consecutive days when appropriate for the application and the light system being used.
The appropriate frequency depends on the intended application, treatment area and the parameters of the system. Consistent use can be incorporated around training, exercise, competition and ongoing maintenance as part of a broader care routine.
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For specific ReGen treatment schedules and application guidance, see our Usage & Applications guide.
Is Red Light Therapy Safe for Horses?
Red light therapy is a non-invasive modality that can be incorporated into equine care when used according to the light system’s recommended application parameters.
Because the eyes are particularly sensitive to concentrated light, direct exposure to the eyes should always be avoided. Treatment should also be applied according to the manufacturer’s instructions, including the recommended session duration and treatment distance or contact.
For most applications, red and near-infrared light is designed to deliver light energy to the intended treatment area without producing the intense heat associated with surgical lasers. Using a system appropriately and consistently is an important part of safe application.
As with any supportive modality, red light therapy should complement—not replace—appropriate veterinary assessment and care when a horse has an injury, persistent pain or a diagnosed condition.
Can Red Light Therapy Be Used on Joints, Tendons and Muscles?
Yes. Joints, tendons and muscles are among the areas where red and near-infrared photobiomodulation are commonly incorporated into equine care programs.
Different tissues have different structures and optical characteristics, which is why light-based applications are often selected according to the area being treated. Near-infrared wavelengths are particularly relevant when applications involve deeper soft tissue, while red wavelengths can contribute to more superficial tissue interaction.
For performance horses, light may be incorporated into routines around training, competition, conditioning and rehabilitation. It can also be used as part of regular maintenance for areas that receive repeated physical workload.
The goal is to provide targeted, consistent light application as part of a broader care program—not to replace proper assessment or rehabilitation when an injury or underlying condition is present.
ReGen Equine systems are designed around the practical anatomy of the horse, with wearable formats that allow light to be positioned directly over commonly treated areas. Explore Products
Can Red Light Therapy Be Used on the Hoof?
Yes. The hoof is an important application area for equine red and near-infrared light.
The hoof presents a unique challenge because light must travel through dense structures before reaching the tissues within the foot. This makes consistent positioning and effective light delivery particularly important when applying light to the hoof and surrounding structures.
ReGen customers have reported significant improvements in their horses’ feet while incorporating red and near-infrared light into their care routines, including horses managing conditions such as laminitis and navicular disease. These customer experiences are encouraging and reflect the growing interest in light-based support for equine hoof care.
Individual results can vary, and conditions such as laminitis and navicular disease require appropriate veterinary and farrier involvement. Red light therapy can be used as a supportive component of a broader hoof-care program rather than as a replacement for diagnosis or conventional care.
ReGen Hoof Boots are designed to provide consistent red and near-infrared light directly around the hoof, making them practical for incorporating light into a regular equine care routine.
Can Red Light Therapy Help With Inflammation?
Photobiomodulation has been studied for its effects on inflammatory processes, and research suggests that red and near-infrared light can influence cellular pathways involved in the body’s inflammatory response.
Rather than acting like an anti-inflammatory medication, photobiomodulation works through light-induced cellular signaling. Research has identified changes involving reactive oxygen species, nitric oxide, calcium signaling and inflammatory pathways, with studies reporting reductions in inflammatory markers under certain conditions.
This makes inflammation one of the areas of interest in photobiomodulation research, particularly in applications involving muscles, joints and other tissues affected by physical stress.
For horses, red and near-infrared light can therefore be incorporated as a supportive modality within a broader care program. The response depends on the application and the light parameters used, which is why ReGen focuses on delivering purpose-designed light for equine use.
ReGen customers have also reported positive results when incorporating red and near-infrared light into their horses’ care routines, including improvements in areas associated with inflammation, soreness and physical workload. These experiences are encouraging and complement the growing body of research exploring photobiomodulation and inflammatory processes.
For the deeper science behind how photobiomodulation interacts with inflammatory pathways, explore our PBM Science guide.
Can Red Light Be Used Before or After Exercise?
Red and near-infrared light can be incorporated into both pre- and post-exercise routines for horses, depending on the purpose of the application.
Before exercise, light may be used as part of a preparation routine alongside appropriate warm-up, stretching and movement. The goal is to support normal circulation, tissue readiness and comfortable movement before physical work.
After exercise, light can be incorporated into a post-work routine to support circulation, comfort and normal tissue recovery following physical workload. This can be particularly useful after training, competition or other demanding exercise.
Many ReGen customers incorporate light into their horses’ routines around regular training and competition, using it as one component of a broader performance and maintenance program.
Light therapy does not replace an appropriate warm-up, cool-down, conditioning program or veterinary and rehabilitation care. Instead, it can be a practical addition to the routine already supporting the horse’s physical health and performance.
For specific guidance on application areas and incorporating ReGen into a horse’s routine, explore our Usage & Applications guide.
How Long Does It Take to See Results From Red Light Therapy?
How quickly a horse responds to red light therapy can vary. Some horses may appear relaxed or more comfortable during or shortly after a session, while other changes may become more noticeable with consistent use over time.
The response can depend on the horse, the area being treated, the reason for using red light therapy and the consistency of the routine. Photobiomodulation is not necessarily a one-time treatment; many horse owners incorporate red and near-infrared light into their regular care, training and maintenance routines.
ReGen customers have reported noticing positive changes at different stages of use, including relaxation and comfort as well as improvements that became more apparent with repeated sessions.
Rather than expecting the same timeline for every horse, consistency and observation are key. Your horse’s individual response is the best guide to how light therapy fits into their ongoing care routine.
For practical guidance on incorporating red light therapy into your horse’s routine, explore our Usage & Applications guide.
Explore the Science Behind ReGen Equine
Curious to learn more? ReGen Equine’s educational resources take you deeper into the science and practical use of red and near-infrared light for horses.
Explore 660nm, 850nm and 940nm, how different wavelengths interact with tissue, and why ReGen uses a Tri-Wave Light System™.
Learn how photobiomodulation interacts with biological tissue and the cellular processes researchers are studying.
Discover practical ways red and near-infrared light can be incorporated into an equine care routine.
ReGen Research Library Explore published research related to photobiomodulation, wavelengths, light delivery and equine applications.
Have More Questions?
Visit our FAQs for quick answers to common questions about red light therapy for horses, including treatment time, frequency, application areas, safety and product use.