Red Light Therapy Q&A: Why I Engineered My Equine Products Differently

I’ve had a LOT of DMs with really good questions about my new “engineered” red light products, so I figured it would be easier to put the common ones in one place and explain some of the science behind my design choices.

I’m an engineer first, which means I tend to go down the rabbit hole. Wavelength, tissue depth, power, dose, coverage area, heat, usability, and what actually makes sense on a horse all matter to me. This is not meant to be a veterinary textbook. It is the reasoning behind why I built these products the way I did.

What makes your red light products different from other equine red light products?

A lot of the portable equine red light products I reviewed use LEDs built around 660 nm red light and 850 nm near-infrared. The configuration every other company had was one 660 nm diode and two 850 nm diodes.

I wanted a broader wavelength combination, so mine use 660 nm, 850 nm, and 940 nm. Instead of repeating the same 850nm wavelength twice, I chose to add an advanced 940nm wavelength, despite the increased costs of manufacturing. The benefits are worth the extra costs.

Why did you choose 940 nm? Isn’t 850 nm enough?

This came from how I think about the horse as the actual treatment target instead of copying a human device and just making it bigger.

A horse is not a large human. Muscle thickness, connective tissue, bone size, hair coat, skin, treatment distance, and the geometry of the area being treated all affect how much light reaches tissue. Hair adds another variable because it can absorb and scatter light before it reaches the skin.

A lot of the way I approached this research probably comes from my nuclear engineering background. I took both radiation shielding and health physics classes as part of completing my degree, so I am used to thinking about what happens to energy between the source and the target, not just what comes out of the source.

In radiation shielding problems, the source strength by itself does not tell you what reaches the other side. You have to think about the material in between, thickness, geometry, attenuation, absorption, scattering, and where the energy ultimately goes. Light moving through biological tissue is obviously not the same physics problem as neutrons or gamma rays moving through shielding, but the engineering thought process is very similar. I wanted to know how much light started at the device, what the horse’s tissues would absorb (or scatter), how much would be reflected or redirected, and how much could actually reach the anatomy I cared about.

That is why I spent so much time looking at absorption, transmission, scattering/deflection, wavelength, tissue depth, hair, pigmentation and treatment geometry instead of just comparing the wavelength numbers printed on product boxes.

Equine-specific penetration research backs up that practical problem. One ex vivo study tested 800 and 970 nm light through equine skin and flexor tendons. Hair color, skin color, skin thickness, clipping or shaving, and wavelength all changed transmission. Clipping or shaving improved penetration, darker hair reduced it, thicker skin reduced it, and the wavelength that transmitted best differed with skin pigmentation. [1] This is one reason where I write out my own instructions for people that buy one of my redlight blankets because treatment times vary depending on the color of your horses fur and if they have a winter coat or not.

An in vivo equine tendon study using 810 nm also evaluated hair clipping and skin preparation because those real-world variables affect transmission. [2]

That is a big reason I wanted a longer near-infrared wavelength in the mix. Adding 940 nm gives the device a third distinct wavelength with its own absorption profile and some awesome published biological responses. It is not just another 850 nm diode.

There is laboratory research showing wavelength-specific responses at 940 nm. In a direct comparison of 810 nm and 940 nm on periodontal-ligament-derived stem cells, 940 nm at 2.5 J/cm² significantly increased cell viability and proliferation at the measured time points, while 810 nm at the same energy density did not produce the same response under that protocol. [3]

Those are human periodontal-ligament stem cells, not an equine suspensory ligament. I am not pretending its EXACTLY the same, but it’s a great use example proving that the 940 nm is biologically distinct enough to be worth adding rather than treating it as redundant alongside 850 nm.

The cartilage data is also interesting for products that can be positioned over joints. A 2025 LED study compared 625, 810, 940, and 1050 nm. In the cell experiments, 940 nm at 52 J/cm² produced the strongest suppression of cartilage-degradation markers and increased markers associated with cartilage matrix. In the mouse osteoarthritis model, that 940 nm protocol reduced cartilage degradation and improved weight-bearing asymmetry compared with untreated controls. [4]

Again, that is not an equine clinical trial and it does not prove my wraps “treat” arthritis, but it is exactly the kind of wavelength-specific evidence that made me add the 940nm wavelength instead of simply stopping at 850 nm.

Why dose matters just as much as wavelength

A wavelength number does not tell you the whole treatment dose.

For photobiomodulation, fluence is usually expressed in joules per square centimeter and is related to irradiance and exposure time:

Fluence (J/cm²) = Irradiance (W/cm²) × Time (s)

Then you still have the horse standing between the LEDs and the target tissue. Hair coat, skin pigmentation, tissue thickness, distance, LED geometry, contact with the body, and the treatment area all affect what actually reaches the tissue.

How is LED photobiomodulation different from laser therapy?

Laser therapy and LED photobiomodulation both use light, but they deliver it differently. Lasers produce coherent light and are often used for more focused applications. LED systems produce non-coherent light and can spread treatment over a much larger area at one time.

The easiest way I explain it is a rifle versus a shotgun. A laser is more like a rifle: narrower, more targeted, and useful when you want to concentrate treatment into a specific area. A large LED wrap is more like a shotgun: broader coverage over a larger treatment area, which is extremely practical for things like wraps, blankets, and other wearable equine devices.

A shotgun is not “worse” than a rifle. It is built for a different job. In the same way, LED therapy is not automatically inferior to laser therapy just because the light is less focused. Broad coverage can be a real advantage when the treatment area is large or when the goal is practical, repeatable use on an actual horse.

There is also no simple rule that coherent laser light always produces a better biological response than LED light. Photobiomodulation is extremely parameter-dependent. Wavelength, irradiance, fluence, treatment time, beam or LED geometry, tissue depth, and the target all matter.

There are different devices, doses, targets, and study designs. That matters more than a broad statement that one wavelength or one type of light source always “works better.”

Higher-powered therapeutic lasers can also require protective eyewear, training, and additional safety controls depending on the device. A portable LED wrap is a very different use case. It’s pretty hard to make a mistake or cause hard but the benefits are tremendous!

Are you planning more red light products, or will you keep changing the designs after launch?

I’m tackling one product at a time.

Once I get a design where I want it, I do not plan on constantly changing it unless customers find a legitimate issue or I see something that clearly needs improvement. I would rather engineer it correctly, test the idea, listen to feedback, and leave a good design alone.

For example, I designed my red light bell boots 6” longer so they can fit larger horses, including my Belgian drafts, and so they can also wrap around other areas of the lower leg instead of being useful only on the hoof.

I changed the shape of my equine back blanket compared to my prototype so it can be repositioned over areas like the hips, stifles, shoulder, and neck instead of being a one-purpose rectangle.

I’ve also developed splint-boot-style red light wraps and poll caps.

The poll cap is especially interesting to me because human research has looked at transcranial photobiomodulation with near-infrared light. Sham-controlled studies using 1064 nm have reported measurable changes in cerebral oxygenation or metabolism under specific protocols, along with changes in visual working-memory performance in another study. [5] [6]

There is also a human cadaver penetration study that caught my attention while I was researching 940 nm. Researchers tested 750 and 940 nm near-infrared laser light through intact, fresh, unfixed human cadaver heads with the detector positioned 4 cm from the skin. They were able to detect both wavelengths after transmission through the full 4 cm, and in the whole-head measurements 940 nm consistently transmitted better than 750 nm. [7]

What it shows is that 940 nm light can physically transmit through a substantial thickness of biological tissue, including skin, soft tissue, skull and brain tissue, under the conditions tested. That was another reason I thought 940 nm was worth taking seriously when I started looking at a poll-cap design.

Those human studies are not direct proof for a 940 nm equine poll cap, and I am not claiming a poll cap “regenerates the brain.” The research is supportive enough that I think wavelength, absorption, scattering, coverage, dose, tissue depth and design are worth evaluating carefully.

The engineering takeaway

I did not add 940 nm because I think it is magic. (although the research shows there is definitely a little sparkle ✨🫶🏻)

I added it because there is overwhelmingly compelling evidence that it does indeed put in a lot of work for equine specific anatomy.

660 + 850 + 940 gives me three distinct wavelength bands instead of two. Published studies show biological responses at 940 nm in ligament-derived stem cells and cartilage models, which gives that third wavelength a research basis of its own. [3] [4]

I wanted broader wavelength coverage, practical treatment geometry, better fit on an actual horse, and a price that makes regular use realistic.

That is what I mean when I call them engineered products.

Educational information only. Photobiomodulation research is highly dependent on wavelength, irradiance, fluence, treatment time, pulsing, tissue type, and device design. Animal-model and human studies do not automatically establish efficacy for an equine consumer device. These products are not a substitute for veterinary diagnosis or treatment.