LED vs. Class 3B vs. Class 4 Lasers: Same Light Family, Different Tools

Red light therapy and laser therapy are often marketed like two rival teams. LEDs get dismissed as “just lights,” while Class 3&4 lasers are introduced like they should enter the barn through a cloud of smoke with their own theme music. 🪩🕺🐴

The actual physics is less dramatic and much more useful 😂

LEDs, Class 3B lasers and Class 4 lasers can all deliver photobiomodulation. Thats fancy terminology for what most people know as “red light/laser therapy. They use red or near-infrared light waves to influence biological processes. What changes is how that light leaves the device, how concentrated it is, how much area it covers, how quickly energy is delivered and how serious the safety program needs to be.

My current VanHorn red light products already use 660, 850 and 940 nm LEDs in broad-coverage designs such as wraps, caps and blankets. In the future, I also want to add a small portable Class 3B laser and a professional Class 4 system. The lasers are not intended to replace the LED line. They would fill different jobs in the same therapy toolbox.

The short answer: which tool does what?

First: LEDs are not fake laser therapy

Photobiomodulation begins when tissue absorbs photons at useful wavelengths and doses. Those photons may come from a laser diode or a light-emitting diode (LED). A cell does not request the devices résumé before responding. It responds to the light that actually reaches it.

That does not mean every LED and laser protocol is interchangeable. Wavelength, irradiance, treatment time, pulse pattern, beam area and total energy all matter. Two devices can both produce near-infrared light and still deliver very different treatment conditions.

Direct comparisons help make that distinction. In a randomized human study, both a low-level laser protocol and an LED protocol produced similar improvements in several short-term wound measures. In a diabetic rat wound study comparing a 904 nm laser with an 850 nm LED, both produced biological effects, but the measured responses were not identical. The devices also used different wavelengths, doses and pulse patterns, which is exactly why “laser versus LED” cannot be separated from the full protocol. [3, 4]

Those are not horse trials, and I am not dressing them up as horse trials - but it is still a useful and applicable comparison. They simply show that useful photobiomodulation is not reserved exclusively for coherent laser light.

My favorite simple analogy: shotgun versus rifle

(Anyone who knows me well, knows im a real big fan of poking holes in targets very far away at high velocities 😂🤓I reload many different calibers, thoroughly enjoy infrared and thermal optics, and my favorite discovery as an adult has been playing with subsonics and high quality suppressors - i might have a suppressed 8.6blk under to my bed 👀 🤣🤙🏻)

I still like the shotgun versus rifle analogy because it explains delivery geometry without requiring a minor in optical engineering:

• An LED wrap is the shotgun. Many emitters distribute light broadly across a tendon region, back, poll or joint area.
• A laser is the rifle. It concentrates optical power into a smaller, more controlled target.

This is not an accuracy insult to LEDs. When I want to cover an entire region, broad distribution is the point. A blanket should not require me to aim 400 tiny laser spots at a horse’s back one at a time. I have a busy life 😅 convenience is key.

Laser light is more directional when it leaves the handpiece. Once it enters hair, skin and other biological tissue, absorption and scattering begin disrupting that tidy beam path. Deeper penetration wavelengths are equally if not MORE important than the power output- which is why I have been so disappointed with all the fancy marketed products that only have 660 and 808/850 wavelengths and nothing longer 🙃

Where VanHorn’s 660, 850 and 940 nm LEDs fit best 💢✨

My existing LED products combine 660 nm red light with 850 and 940 nm near-infrared light. Instead of relying on one concentrated spot, the products place many emitters across a wearable treatment area.

That design has several practical advantages for horses:

• Broad coverage: many LEDs can treat an entire region instead of a single point.
• Hands-free use: a properly fitted wrap, cap or blanket stays positioned while the session runs.
• Curved anatomy: flexible products can follow a leg, hock, poll or back better than a rigid handpiece.
• Repeatable placement: the same product can cover the same general area from one session to the next.
• Low operator workload: one person can secure the product instead of continuously scanning a probe.
• Multiple wavelengths: 660, 850 and 940 nm provide a mixed red and near-infrared spectrum across the treatment field.

The tradeoff is concentration. Optical power is distributed across a larger area, so an LED product is usually not trying to deliver the same point intensity as a laser probe. That is not a design failure. It is the price of broad coverage, just as a floodlight and a spotlight are built for different jobs.

LEDs make the most sense when convenience and coverage matter: a long tendon region, a broad back or shoulder area, the poll, hocks, or routine treatment where the horse can stand quietly wearing the device.

Where a portable Class 3B laser fits 

A portable Class 3B laser interests me because it fills the space between a broad LED wrap and a large professional Class 4 unit.

Its strengths are:

• Precision: concentrated light can be directed at a smaller, clearly defined area.
• Portability: a compact handpiece is easy to move between stalls, trailers and treatment locations.
• Controlled point dosing: the operator can work through specific points or small zones.
• Generally lower thermal load than Class 4: useful when the goal is controlled photobiomodulation without aggressive heating.
• Lower expected cost and size: a portable platform can be more attainable than a full professional Class 4 system.

The tradeoff is treatment time. Lower power takes longer to deliver the same number of joules. That is manageable over a small target. It becomes tedious if somebody decides to treat an entire Belgian draft one postage stamp at a time. Geometry wins again. 🐴

The Class 3B concept I am developing is meant to complement my LEDs. The LED product covers the whole neighborhood; the portable laser lets the operator knock on one specific door.

Where Class 4 becomes useful ⚡

Class 4 changes the workflow primarily because higher power can deliver energy FAST. The vet can scan a handpiece over a larger muscle group or work across a defined tendon or ligament region without spending an unreasonable amount of time at each small point.

For horses, that makes Class 4 particularly interesting for:

• Large areas, shoulder and hindquarter muscle groups.
• Veterinarian-identified tendon and ligament rehabilitation areas.
• soft tissue around joints.
• Professional settings where treatment time and daily throughput matter.
• Protocols that require substantial energy delivery across a larger treatment field.

The tradeoff is responsibility. More power means less time between “useful energy delivery” and “why is this getting hot?” Handpiece movement, spot size, coat, pigment, treatment distance and duty cycle all matter. Class 4 equipment should be treated like professional equipment because that is exactly what it is - and why it’s typically used exclusively by people with a medical license. Some states even require Class 4 lasers to be registered with their state health regulators (*cough MA, FL, and TX 👀)

Laser class is a hazard category, not a therapy ranking

The FDA classifies lasers according to their potential hazard. Class 3B lasers present an immediate eye hazard from direct-beam exposure and can create skin hazards. Class 4 lasers can injure eyes or skin through direct or reflected exposure and may also present a fire hazard. [1, 2]

So “Class 4” does not mean fourth place, fourth generation or four times better. It means the accessible laser emission exceeds the Class 3B limit under the applicable classification rules and requires more serious controls.

The class number tells me how much I need to respect the light beam. It does not tell the horse’s mitochondria to be extra impressed. My dad has been blind for all of my adult life and I take vision protection very seriously- if you lose it, it doesn’t come back so you dont get a second chance.

Dose: where the actual engineering lives

The basic math is simple:

Energy in joules = power in watts × time in seconds

Fluence in J/cm² = energy ÷ treatment area

A 0.5 W source operating for 120 seconds delivers 60 joules. A 10 W source can deliver 60 joules in six seconds. That does not make the biological treatment identical because spot size, irradiance, wavelength, pulsing, handpiece movement and heating still matter. It does show the practical advantage of high power: more joules can be delivered in less time.

For LED products, total device wattage can also be misleading if it is not connected to treatment area and measured optical output. A large array may have substantial total power while distributing it over many square centimeters. A small laser may have lower total power but much higher intensity at one spot.

Higher wattage does not rescue a bad protocol. A sports car reaches the wrong address faster too.

What is the light actually doing?

Photobiomodulation begins when tissue molecules absorb photons. That absorption can influence mitochondrial and redox signaling, vascular signaling, inflammatory mediators and cellular behavior. It is not accurate to say the device simply “turns light into ATP” like gasoline into a truck.

In one equine laboratory study, bone-marrow-derived mesenchymal stem cells exposed to a specific 1064 nm high-intensity laser protocol remained viable and showed increased expression of IL-10 and VEGF 24 hours later. That is measurable evidence of a cellular response, but it was an in vitro experiment, not proof that one preset heals every injury in a living horse. [5]

The biological response is dose-dependent. Too little light may not deliver enough photons to the target. Too much power, too much time or too small a spot can produce excessive heat or an unhelpful dose. Goldilocks apparently has a photobiomodulation protocol now. 🙄

Does a laser automatically penetrate deeper than an LED?

Not in the neat cartoon version marketing departments love.

A laser can concentrate more optical power into a smaller area, and a higher-power laser can send more photons toward tissue per second. That can make it easier to deliver a useful surface dose quickly. But wavelength, hair, pigment, skin thickness, beam area and tissue optics still determine how much energy reaches the deeper target.

An ex vivo study tested 800 and 970 nm laser light through equine skin and flexor tendons. Hair color, skin color, skin thickness, clipping or shaving and wavelength all changed transmission. Most of the applied energy was absorbed or scattered before reaching the deeper structures. Depending on the conditions, the superficial digital flexor tendon absorbed about 1% to 20% of the applied energy and the deep digital flexor tendon absorbed about 0.1% to 4%. [6]

An in vivo study using an 810 nm, 500 mW probe also found that clipping increased transmission through the equine distal limb. Cleaning with alcohol without clipping did not produce the same improvement. [7]

The takeaway is not that deep treatment is impossible. It is that no emitter gets to ignore the horse standing between the device and the target.

What the equine tendon and ligament research says

The strongest horse-specific clinical evidence in this comparison currently belongs to selected high-power laser protocols, especially tendon and ligament research.

In a standardized controlled study, researchers created suspensory branch lesions in 12 Warmblood horses. Two lesions in each horse received a multi-frequency high-power laser protocol daily for four weeks, while the other lesions served as controls. Treated lesions showed several improved ultrasound and MRI measurements, including smaller lesion size at specific follow-up points and lower MRI signal. The researchers were appropriately careful: imaging suggested improved healing, but the original study could not prove greater tensile strength. [8]

A later histological follow-up from the same model found differences consistent with more advanced remodeling in treated tissue, including lower collagen type III expression in laser-treated lesions. Even so, an experimental lesion model is not every naturally occurring suspensory injury, and the exact protocol matters. [9]

A separate clinical study involving 26 performance horses with naturally occurring tendon or ligament injuries compared rehabilitation alone with rehabilitation plus 15 high-intensity laser sessions. The laser group showed improvements in lameness, swelling and ultrasonographic lesion percentage. The results are encouraging, but the study was small and cannot make every wavelength, device or preset interchangeable. [10]

That distinction matters: a study on one protocol supports that protocol, not every machine with “Class 4” printed on the case. This is an important distinction because most companies “market” incorrectly and cite studies that very loosely support their products 😬

Pigment and heat deserve their own paragraph

In a study of 20 Thoroughbreds, the same high-intensity laser treatment increased surface temperature over pigmented skin but decreased it over non-pigmented skin, while vein diameter increased in both groups. Another equine study found a significant increase in skin-surface temperature over the superficial digital flexor tendon immediately after HILT. [11, 12]

Controlled warmth may be part of some Class 4 protocols, but it is another reason one generic preset cannot pretend every horse has the same optical properties. Dark coat, clipped white leg, thick winter hair and thin-skinned chestnut are not interchangeable laboratory samples.

Safety changes dramatically across the three tools

VanHorn LED products do not create the same concentrated laser-beam hazard as Class 3B or Class 4 devices. They should still be used according to their instructions, kept in good condition and never treated like toys.

Class 3B and Class 4 lasers require a controlled treatment area and wavelength-matched protective eyewear. Near-infrared beams are especially deceptive because they may be invisible while still capable of retinal injury.

A proper laser treatment program needs:

• Wavelength-matched protective eyewear for every person in the controlled area.
• Appropriate equine eye protection and secure handling.
• Removal or control of reflective tags, tack, mirrors and polished metal.
• Clear emission indicators, key control and safety interlocks where required.
• Protocols that account for coat, pigment, treatment area, spot size and thermal response.
• Veterinary diagnosis before treating an unidentified injury.

Federal performance standards require additional engineering controls for Class 3B and Class 4 systems. Those controls are not decorative buttons added to make the case look expensive. [2]

Why I want all three in the VanHorn toolbox

Some people ask me “what makes you qualified to sell/design/modify these products?” and it gave me pause - I jokingly thought to myself “name me someone MORE qualified to develop these products… 🤷🏻♀️ why are people buying these products from random salespeople/online instead of from an ACTUAL engineer who can answer every question and understands the physics behind them?” 😂🤦🏻♀️ nothing is more annoying (to me) than reaching out for product support on a device and getting passed from salesperson to salesperson that cant answer any of my technical questions 🫠 like please just hand the phone to a fellow nerd who can help me…

so here I am now working on a full line of high quality products at attainable prices 💕

• VanHorn 660/850/940 nm LED products: broad, wearable, hands-free coverage for practical routine use.
• Portable Class 3B laser : concentrated point treatment in a compact barn-friendly device.
• Professional Class 4 platform: faster energy delivery across larger or deeper veterinarian-identified treatment regions, with professional controls and safety requirements.

If I cannot explain why a product belongs in the line without hiding behind a bigger wattage number or a dramatic laser-class label, then I have not engineered the manual, or the product, well enough.

The bottom line

LEDs, Class 3B lasers and Class 4 lasers belong to the same photobiomodulation family, but they are built for different workflows.

• Choose broad LED-coverage when convenience is key, hands-free treatment and coverage of a large or curved region matter.
• Choose portable Class 3B-precision when a smaller target and compact handpiece make more sense than a wearable array.
• Choose Class 4-speed when a trained operator needs to deliver substantial energy efficiently across a larger professional treatment area.

The laser is not automatically better because the beam is narrower. The LED is not inferior because the light is broader. And Class 4 does not arrive wearing a tiny crown. 👑

The right tool depends on the horse, the target, the dose, and the job.

This article is for educational purposes only and is not veterinary advice. Photobiomodulation evidence is protocol- and condition-specific. Laser devices can cause serious eye and skin injury and require appropriate training, controls and wavelength-matched eye protection. Light therapy does not replace diagnosis, imaging, controlled rehabilitation or veterinary treatment.

References

1. U.S. Food and Drug Administration. Laser Products and Instruments: laser hazard classes and federal requirements.
2. Electronic Code of Federal Regulations. 21 CFR 1040.10, Laser products.
3. Lima ACG, et al. Photobiomodulation (Laser and LED) on sternotomy healing in hyperglycemic and normoglycemic patients: a randomized, double-blind study. Photomedicine and Laser Surgery. 2017;35(1):24-31.
4. Tatmatsu-Rocha JC, et al. Mitochondrial dynamics and collagen production in diabetic wound healing: comparison of 904 nm laser and 850 nm LED. Journal of Photochemistry and Photobiology B. 2018;187:41-47.
5. Peat FJ, Colbath AC, Bentsen LM, Goodrich LR, King MR. In vitro effects of high-intensity laser photobiomodulation on equine bone marrow-derived mesenchymal stem cell viability and cytokine expression. Photomedicine and Laser Surgery. 2018;36(2):83-91.
6. Duesterdieck-Zellmer KF, Larson MK, Plant TK, Sundholm-Tepper A, Payton ME. Ex vivo penetration of low-level laser light through equine skin and flexor tendons. American Journal of Veterinary Research. 2016;77(9):991-999.
7. Ryan T, Smith RKW. An investigation into the depth of penetration of low level laser therapy through the equine tendon in vivo. Irish Veterinary Journal. 2007;60:295-299.
8. Pluim M, et al. High-power laser therapy improves healing of the equine suspensory branch in a standardized lesion model. Frontiers in Veterinary Science. 2020;7:600.
9. Pluim M, et al. Histological tissue healing following high-power laser treatment in a model of suspensory ligament branch injury. Equine Veterinary Journal. 2022;54(6):1114-1122.
10. Zielińska P, et al. Effects of high intensity laser therapy in the treatment of tendon and ligament injuries in performance horses. Animals. 2020;10(8):1327.
11. Zielińska P, et al. Effect of high-intensity laser therapy on skin surface temperature and vein diameter in pigmented and non-pigmented skin in healthy racehorses. Animals. 2021;11(7):1965.
12. Zielińska P, et al. Photothermal effects of high-intensity laser therapy on the superficial digital flexor tendon area in clinically healthy racehorses. Animals. 2022;12(10):1253.