Therapeutic laser (photobiomodulation) is increasingly used in horses to aid tendon/ligament repair. Recent studies show that LLLT (Low Light Laser Therapy) can accelerate suspensory ligament healing and improve clinical outcomes. For example, a controlled trial demonstrated significantly improved healing (smaller lesion size on ultrasound/MRI and faster tissue repair) in laser-treated suspensory branch injuries.

In a large clinical series (150 sport horses), horses treated with high-power laser therapy showed marked improvement in lameness and lesion appearance by 2 weeks into therapy, with lower re-injury rates than typically seen with conventional rest alone. These findings align with laboratory evidence that laser light stimulates fibroblast proliferation, collagen alignment, angiogenesis, and reduces inflammatory mediators in tendon tissue. In short, LLLT provides a non-invasive, drug-free method to promote suspensory ligament healing and reduce pain. The key is delivering an adequate dose of light (at the right wavelengths) consistently over the injured area.

Below are evidence-based guidelines for frequency, power, and treatment time using a device with specifications similar to the Healix Questrian (470 nm, 635 nm, 850 nm, 905 nm; up to ~1300 mW output; 4–60 min range). As with any treatments, we recommend consulting with your veterinarian to determine the best protocol and treatment frequency for your horse’s specific condition.

Treatment Frequency and Duration of Therapy

Treat Frequently in the Initial Phase

Clinical protocols and veterinary guidelines recommend treating suspensory injuries frequently (at least 3–7 times per week) during the initial healing phase. Daily sessions are often ideal, especially in the first 2–4 weeks:

Research Protocols: In published studies, lasers were applied once daily during the acute healing period. For example, one equine suspensory branch lesion study treated horses daily for 4 weeks (20-minute sessions). A retrospective clinical report on 150 cases used laser therapy once daily for 2 weeks as the initial course. These intensive schedules yielded significant improvements by 2–4 weeks.
Guidelines: The World Association for Laser Therapy (WALT) similarly advises daily treatment for ~2 weeks, or every other day for 3–4 weeks, for tendon injuries. This frequent regimen jump-starts the healing process. In practice, many veterinarians will treat 5–7 days per week for the first 2–3 weeks, then reassess.

Tapering Frequency

As the horse improves, the treatment frequency can often be reduced. After the initial daily/near-daily phase, one may scale back to 2–3 sessions per week for the next several weeks. For example, if significant healing is observed after 2–4 weeks of daily therapy, continuing treatments twice weekly for a few more weeks can help consolidate healing. This taper aligns with guidelines suggesting to reduce the laser dose by ~30% once acute inflammation is controlled (which can be achieved either by lowering frequency or intensity).

Chronic or severe suspensory injuries may benefit from a longer overall course (e.g. an initial 4-week daily phase followed by several weeks of gradually less frequent therapy). In all cases, frequent early therapy is key – consistency and repetition yield the best results. For acute suspensory desmitis (very inflamed), daily treatment can help quickly control inflammation and pain; for subacute or chronic lesions, every-other-day may suffice if daily sessions are not feasible.

Total Treatment Course

Many horses require on the order of 10–20 total sessions for maximal benefit. In the published reports, horses received ~14–28 laser sessions over a few weeks. Clinical case series have documented return to soundness with similar or slightly longer courses – for example, one report noted 97% of horses with tendon/ligament injuries (including suspensory lesions) regained soundness after laser therapy (904 nm) applied over several weeks, with ~90% still performing well 1–2 years later.

This highlights that a sufficiently long treatment program (several weeks of regular therapy) is crucial for lasting recovery. Always tailor the frequency to the horse’s response: if improvement plateaus, additional treatments or other therapies may be considered; if the injury is healing well, the interval between treatments can be gradually extended.

Laser Power Settings and Dosage Considerations

Wavelengths and Penetration

The Healix Questrian device emits multi-wavelength light (470 nm blue, 635 nm red, 850 nm & 905 nm near-infrared). This broad spectrum is advantageous: red and blue light affect superficial tissues (skin, circulation) while near-IR (850/905 nm) penetrates deeper to reach ligament fibers.

Research shows that in horses, light in the 800–970 nm range penetrates skin and sub-tissues most effectively. (Notably, penetration varies with skin/hair color: lighter skin and clipped hair transmit significantly more light.) The 905 nm wavelength in this device is a GaAs laser often used in “superpulsed” mode to drive light deeply with high peak power. In one case series for equine tendon injuries, a 904 nm pulsed laser (90 W peak) was chosen specifically for its depth penetration, contributing to the high success rate.

Bottom line

When treating a suspensory ligament, maximize use of the near-infrared output, as those wavelengths will have the greatest chance of reaching the injured ligament fibers beneath skin and fascia. Ensure the laser is applied directly over the lesion (and from different sides of the limb if possible) to bathe the entire injury in light.

Power Output

The device’s total output is up to ~1300 mW (1.3 W). For a suspensory desmitis, using higher power settings (near the maximum output) is generally recommended to deliver a sufficient dose to deeper tissues. Published equine protocols have used class-4 lasers up to 15,000 mW (15 W), but run for shorter times to deliver the needed energy.

With a 1.3 W device, you will compensate by treating for a longer duration per session (see next section) and focusing the beam effectively. In practice, set the device to its high setting or continuous wave mode if available, so that the greatest light intensity is emitted. This ensures adequate photons reach the suspensory ligament, which lies under skin and (in the proximal area) under the flexor tendons.

Clipping the hair and cleaning the skin at the treatment site is strongly advised; a veterinary study demonstrated that unclipped hair and dark skin can absorb a large fraction of the laser energy, dramatically reducing the dose that reaches deeper tissues. Clipping/shaving can greatly improve penetration efficiency, meaning more of that 1300 mW actually reaches the ligament fibers.

Dosage (Energy) Targets

Optimal LLLT dosage is often expressed in energy (Joules) delivered. For tendon/ligament injuries, experts recommend a fairly high energy dose per session to stimulate healing. Human therapy guidelines (WALT) suggest on the order of 4–8 Joules per point along an injured tendon (with several points treated), and note that total doses can vary ±50% of recommendations without losing efficacy.

In horses, due to larger and deeper structures, effective doses tend to be higher. High-powered equine laser studies have delivered tens of Joules per cm² of the lesion: for instance, one protocol delivered roughly 25 J/cm² over the suspensory branch region each session.

Another report described about 250 J per cm³ of tissue treated (reflecting a very high energy delivered into the lesion volume). While such doses are achieved with big class-4 lasers, a lower-powered device can approximate them by increasing treatment time per area.

Aim to deliver at least several dozen Joules in total to the suspensory lesion in each session. For example, if you treat a ~20 cm² area at 1.3 W for 10 minutes, the total energy delivered is 780 J (which averages 39 J/cm²) – a robust dose. It’s better to err on the higher side of dosage (within safety limits) for chronic ligament injuries, as under-dosing is a common reason for LLLT “no response” cases.

That said, extremely high doses have diminishing returns, so once you’ve delivered on the order of 500–1000+ Joules to a lesion in one session, increasing it further is unlikely to provide extra benefit in that treatment. Most protocols fall in a therapeutic window; for context, WALT recommends staying within ~50% above or below the target dose to ensure efficacy.

Power Density and Safety

When using high power, keep the laser moving over the area rather than holding it still on one spot. This prevents hot spots and ensures even energy distribution. LLLT guidelines cap the power density around 100 mW/cm² for tendon therapy to stay in the “low-level” (non-thermal) range. With a 1300 mW device, this limit is reached if the beam is confined to ~13 cm² or smaller – which is indeed the typical size of a suspensory branch injury. By continuously scanning the laser over the lesion site (and a margin of surrounding tissue) you will avoid excessive heating of any one point.

All studies report that laser therapy, when applied correctly, is very safe and well-tolerated by horses (no adverse effects other than occasional temporary tingling or warmth on the skin). In one study, daily 20-minute high-power laser sessions were described as “effective and uncomplicated in all injured horses,” with no negative side effects noted.

To summarize power usage: use the highest power your device allows, but apply it dynamically – covering the whole injury region – to achieve a high dose without tissue overheating.

(Tip: Many equine therapists use a combination of continuous and pulsed settings during a session. For example, you might divide the treatment time into phases – some time in continuous wave (full power) to deliver bulk energy, and some time pulsing at various frequencies (e.g. 5oo Hz, 1000 Hz, etc.) to leverage potential photobiomodulation effects at different pulse rates. Pulsing can also reduce average power if thermal buildup is a concern. If your device has preset programs, use the program on the Healix Questrian designed for “Tendon/Ligament” which likely modulates these parameters appropriately.)

Treatment Time per Session

Session Length

For treating a suspensory ligament injury, typical LLLT session times range from about 5 minutes up to 20–30 minutes per limb, depending on the device power and area treated. With the Healix Questrian (1.3 W max), plan on a longer treatment time (10–20 minutes) to ensure an adequate dose, especially for a deep or extensive lesion. This falls well within the device’s 4–60 min capability.

Empirically, the most successful studies used ~20 minute treatments: e.g. 20 minutes per session was the fixed duration in one proven protocol, and this was sufficient to yield significant healing over 4 weeks. A smaller area or a very superficial lesion might be adequately treated in 5–10 minutes at full power, but most suspensory desmitis cases will benefit from closer to 15–20 minutes of illumination per session.

This allows you to slowly scan the laser across the entire injury site (and any associated swelling), making multiple passes. If the injury spans a large region (for instance, a long portion of the suspensory or both branches), you may split the time between sections or simply spend longer (up to the higher end of the range, 30–40 minutes total) to cover everything.

Dosage vs. Time

Remember that treatment time is the means to deliver the desired energy dose. You can calculate a rough timeframe based on energy goals: for example, if you target ~100 J to a certain part of the ligament, at 1.3 W that requires ~77 seconds of exposure (since Power×Time = Energy). In reality, because of movement and the need to cover area, you will spend longer. Many veterinarians will allocate a set time like “5 minutes on lesion site A, 5 minutes on site B, and 5 minutes on site C,” depending on the lesion’s size/locations, to ensure all parts of the injury get treated. This often totals ~15 minutes.

As another guide, human LLLT guidelines suggest 20–300 seconds per point on a tendon– if one extrapolates to an equine suspensory (which might correspond to, say, 6–8 “points” along the ligament), you arrive at a few minutes of total irradiation. However, because horses have thicker tissue and more scattering of light, in practice we extend the time substantially to get enough light through. Plan for at least several minutes and up to ~20 minutes per session for suspensory lesions.

If using lower power settings (for a mild case or very acute inflammation), you might go on the longer end of the time range to still deliver energy. The device’s range up to 60 minutes is generally not utilized all at once for a single site – extremely long durations can lead to diminishing returns. But it does allow treatment of multiple regions in one session (for example, both front limbs, or a suspensory plus another injury, could be treated sequentially within that 60-minute window if needed).

Treatment Technique

During the session, keep the laser probe slightly above or in light contact with the skin, perpendicular to the limb, and move it slowly along the suspensory ligament. Cover the entire injury zone and a small margin around it. If the lesion is a branch injury (around the fetlock area), treat from the side and back of the branch; if it’s a proximal suspensory injury (higher up near the cannon bone), you may need to treat from the medial and lateral sides of the limb, since the suspensory is beneath the flexor tendons – this multi-angle approach can help circumvent shadowing by overlying tissues.

Maintain movement to avoid any heat buildup (the horse’s skin should feel just warm, not hot, after a session). Many practitioners use a “painting” or scanning technique for 5–10 minutes, then hold the probe over specific sore points for an extra minute or two (to give those spots an extra dose), and then finish by scanning again. This ensures both broad coverage and focused treatment of the worst areas.

Summary of Recommendations (Frequency, Power, Time)

Frequency

Start with daily treatments if possible, or at least 5+ sessions per week for the first 2–4 weeks. This intensive phase is when laser therapy has the greatest effect on modulating inflammation and jump-starting tissue repair. Evidence: Daily laser was used in research horses with suspensory lesions, yielding faster improvement in lesion size and lameness scores within weeks. Published guidelines also endorse daily or alternate-day therapy in 2–4 week cycles for tendon injuries. After the initial period, taper to 2–3 sessions per week as healing progresses. Continue therapy for a sufficient overall duration (often 4–8 weeks total, depending on severity) to maximize collagen maturation and minimize re-injury risk.

Power Settings

Utilize the full spectrum of the device, but emphasize the 850 nm and 905 nm near-infrared outputs for depth. Use high power (near 1300 mW) continuous wave if available, especially for deeper portions of the suspensory. If the device offers preset programs or pulsing frequencies, use those designed for “tendon/ligament” which typically drive higher intensities with some pulsed modulation. Always clip the hair and clean the area to reduce light loss. Keep the handpiece moving to distribute the dose and avoid heat spots.

Evidence

Light in the near-IR range penetrates best through equine tissue (800–970 nm proved most effective in ex vivo tests). A multi-wavelength high-power laser (635–980 nm) was successfully used in studies, applied at up to 15 W with continuous movement to avoid burns. Even lower-power 904–905 nm lasers (class 3B superpulsed) have shown excellent clinical results in suspensory and flexor tendon healing – highlighting that 905 nm is a beneficial wavelength for these injuries. In practice, deliver as much power as safely possible: “adequate power and dose are critical to reach the ligament”.

Dose & Time per Treatment

Aim to deliver a therapeutic energy dose on the order of tens to hundreds of Joules into the suspensory ligament each session. For a 1.3 W device, this means treatment times roughly in the 10–20 minute range per site (adjust up or down based on area size and power used). In research, 20 minutes was a common session length with high-powered lasers, and this produced significant biologic effects (improved fiber alignment, smaller lesions on follow-up). With a portable 1.3 W unit, you might treat, for example, 3–4 minutes over each of several points or segments of the ligament (totaling ~15 min to cover the whole region).

Ensure the laser beam is applied to all portions of the lesion (per guidelines, “irradiation should cover most of the pathological tissue” in the tendon). If needed, you can treat in two passes (e.g. 10 min, short break, then another 10 min) to reach a higher total energy without causing discomfort. Evidence: Clinical guidelines for LLLT suggest around 4–8 J per point on human tendons, which typically entails around 1–3 minutes per point with class 3B lasers. In horses, much higher doses per session have been used successfully (e.g. ~25 J/cm² in a suspensory lesion), requiring longer exposure.

All reported studies that showed positive outcomes delivered substantial treatment times or energy (either multiple minutes per spot or high total Joules); very short treatments (e.g. under 1–2 minutes total) are likely insufficient for an injury as significant as a suspensory desmitis.

In summary, for a suspensory ligament injury you should treat early, treat often, and treat thoroughly with your multi-wavelength laser. A reasonable protocol with the Healix Questrian device would be: daily 15-minute sessions at maximum power for about 2 weeks (ensuring the 850/905 nm wavelengths are reaching the site), then continuing 3x weekly for another few weeks or until ultrasound confirms adequate healing.

This approach is supported by peer-reviewed studies showing faster resolution of lesions and lameness with LLLT. By following these guidelines on frequency (daily/very frequent initially), power (high, with deep-penetrating near IR light), and time (sufficient minutes to deliver a high dose), you can optimize the chances of a positive outcome in suspensory ligament healing. Always integrate laser therapy with good rest and rehabilitation practices, and monitor progress via veterinary exams. LLLT is a valuable adjunct – when applied with the proper parameters, it can significantly accelerate a horse’s return to soundness from suspensory injuries.

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Legal Disclaimer:
The information provided in this response is for educational and informational purposes only and should not be considered medical advice. Always consult with a licensed veterinarian before starting any treatment for your horse. Healix Lasers and its affiliates do not diagnose, treat, cure, or prevent any disease or medical condition. The use of laser therapy should be guided by professional veterinary recommendations. Healix Lasers is not liable for any misuse or unintended consequences resulting from the application of this information or device.

Sources:

Pluim et al. (2020). Front. Vet. Sci. – Multi-frequency high-power laser vs. placebo in equine suspensory branch lesions (daily 20min treatments)
pmc.ncbi.nlm.nih.gov
Pluim et al. (2018). Res. Vet. Sci. – Retrospective 150-horse study (laser daily × 2 weeks)
pmc.ncbi.nlm.nih.gov
Jaafar et al. (2021). Arch. Razi Inst. – 50 racing horses with tendon injuries treated with 15W laser (daily 20min for 2 weeks)
pmc.ncbi.nlm.nih.gov
Petermann (2016). Am J. TCVM – Case series 29 horses, 904 nm laser + acupuncture (90%+ return to work)
ajtcvm.org
Lötters et al. (2016). Am. J. Vet. Res. – Ex vivo equine tissue penetration (importance of wavelength, clipping)
avmajournals.avma.org
World Assoc. for Laser Therapy (2010) – Dose recommendations for 780–860 nm lasers (tendinopathies)
waltpbm.org

Laser Therapy for Equine Suspensory Ligament Injuries