Treatments

Laser therapy: how it works

A gentle, non-invasive treatment for pain and healing. How therapeutic laser works, what the studies show in dogs, cats and horses, and what to expect at a session.

By The Animal Physio Co 5 min read

A merle collie beside the words "Laser therapy: how it works"

Therapeutic laser is one of the gentlest treatments we use. There are no needles and no sedation is needed. It's also backed by a growing body of research in dogs, cats and horses. Here's how it works and what the studies show.

Key points

  • Therapeutic laser, also called photobiomodulation, uses red and near-infrared light to boost cells' energy production and calm inflammation.1,2
  • In a placebo-controlled trial, most dogs with elbow arthritis given laser were able to reduce their anti-inflammatory medication.3
  • Studies have also found benefits after surgery and dental cleaning, for chronic wounds, and for ligament healing in horses.4,5,6,7
  • It's non-invasive, and in studies it was well tolerated without sedation.8,9

What laser therapy is

Therapeutic lasers use specific wavelengths of light to stimulate healing and ease pain, a process called photobiomodulation. Unlike surgical lasers, they don't cut or burn tissue. The light passes through the skin into the tissues beneath, where the treatment does its work.

How it works

The leading explanation is that light is absorbed by an enzyme called cytochrome c oxidase in the mitochondria, the energy factories of cells. This frees up the enzyme, so cells produce more of their energy molecule, ATP, and release signals that switch on repair.2,10 One of the most reproducible effects is a reduction in inflammation.1

The dose matters. Too little light has little effect, and too much can reduce the benefit,1 which is why treatment should be planned by a trained practitioner.

What the research shows

Arthritis in dogs

  • In a placebo-controlled trial of 20 dogs with elbow arthritis, 9 of the 11 dogs given laser were able to reduce their anti-inflammatory dose, compared with none of the dogs given a sham treatment. Their lameness and pain scores improved too.3
  • In a double-blind trial of 20 dogs with hip arthritis, laser gave better pain and function scores than a three-week course of an anti-inflammatory drug.11
  • In 23 arthritic dogs given six weekly sessions, daily step counts measured by activity monitors rose from about 1,100 to over 8,400, and half the dogs needed less pain medication. This study didn't have a comparison group.9
  • Combining laser with joint injections gave greater and longer-lasting improvement in dogs with hip arthritis than either treatment alone.8

International guidelines on arthritis in dogs recommend rehabilitation and physical therapy, which they define to include photobiomodulation, at every stage of the disease,12 and the AAHA pain-management guidelines include laser among the physical treatments for pain.13

After surgery, dental work and wounds

  • A single laser session after an elective abdominal operation gave dogs lower pain scores in the first hours, and more of them were eating by eight hours.4
  • In 47 dogs, laser after a dental clean reduced gum inflammation from the first day to two weeks later.5
  • In dogs with long-standing wounds, the wound area shrank by 57–62% in 15 days with laser, compared with 42% with standard care alone.6
  • After spinal disc surgery, dogs given laser alongside rehabilitation showed better neurological improvement.14

Cats

In cats with early gum disease, a week of laser after a dental scale reduced the depth of the gum pockets far more than an antiseptic alone (1.24 mm vs 0.27 mm).15 Veterinary guidelines describe laser as potentially "a tolerable and effective form of therapy" for cats, but note that repeated trips to the clinic can limit how well it works for many of them.13 That's one reason home visits suit cats so well.

Horses

  • High-power laser improved the healing of suspensory ligament injuries in horses: the treated injuries were smaller on ultrasound and MRI,7 and the healing tissue was better organised under the microscope.16
  • In 61 competition horses with back pain, laser therapy reduced pain and stiffness.17
  • A 2025 review concluded that high-power laser "can be safely used" for tendon and ligament injuries in horses.18

Is it safe?

Yes, when it's done properly. In studies, dogs were treated without sedation and the treatment was well tolerated, and horses "tolerated the therapy well".7,8,9 Good practice includes:10,19

  • Protecting the eyes. Everyone in the room wears safety glasses, and the beam is never aimed near the eyes.
  • Avoiding certain areas, such as known tumours and the abdomen of a pregnant animal.
  • Keeping the probe moving so the skin never gets too warm, with extra care over dark skin and coats.

Darker coats absorb more of the light before it reaches the tissues,20 so we adjust the settings for each animal.

What a session involves

We move a handheld probe slowly over the area being treated. Each area takes from under a minute to a few minutes, depending on the animal's size and coat colour.21 Most animals feel only a gentle warmth: in healthy dogs, skin temperature rose by up to 5 °C during treatment.22

Courses vary with the condition. Some studies used weekly sessions,9 others a more frequent "loading" phase of several sessions in the first week or two, tapering to maintenance sessions,8 and short daily courses are sometimes used for wounds and after surgery.23 We'll recommend a plan for your animal and adjust it as it responds.

How laser fits into physiotherapy

Laser works best as part of a wider plan. In the studies above, combining it with other treatments, such as joint injections or a rehab programme, gave the best results.8,14 For most animals, exercise remains the foundation, with laser helping to ease pain so they can move and strengthen more comfortably.

Because we're mobile, we bring the laser to you: at home for dogs and cats, and to the yard for horses. If you'd like to know whether laser could help your animal, book an assessment.

References

  1. Hamblin MR. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophysics. 2017;4(3):337–361.
  2. de Freitas LF, Hamblin MR. Proposed mechanisms of photobiomodulation or low-level light therapy. IEEE Journal of Selected Topics in Quantum Electronics. 2016;22(3):7000417.
  3. Looney AL, Huntingford JL, Blaeser LL, et al. A randomized blind placebo-controlled trial investigating the effects of photobiomodulation therapy (PBMT) on canine elbow osteoarthritis. Canadian Veterinary Journal. 2018;59(9):959–966.
  4. Alves JC, Filipe A, Santos A. Post-surgical photobiomodulation therapy improves outcomes following elective gastropexy in dogs. Lasers in Medical Science. 2024;39(1):211.
  5. Alves JC, Jorge P, Santos A. The effect of photobiomodulation therapy on inflammation following dental prophylaxis. Journal of Veterinary Dentistry. 2024;41(1):26–30.
  6. Hoisang S, Kampa N, Seesupa S, et al. Assessment of wound area reduction on chronic wounds in dogs with photobiomodulation therapy: a randomized controlled clinical trial. Veterinary World. 2021;14(8):2251–2259.
  7. Pluim M, Martens A, Vanderperren K, 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.
  8. Alves JC, Santos A, Carreira LM. A preliminary report on the combined effect of intra-articular platelet-rich plasma injections and photobiomodulation in canine osteoarthritis. Animals. 2023;13(20):3247.
  9. Barale L, Monticelli P, Adami C. Effects of low-level laser therapy on impaired mobility in dogs with naturally occurring osteoarthritis. Veterinary Medicine and Science. 2023;9(2):653–659.
  10. Mosley C, Edwards T, Romano L, et al. Proposed Canadian consensus guidelines on osteoarthritis treatment based on OA-COAST stages 1–4. Frontiers in Veterinary Science. 2022;9:830098.
  11. Alves JC, Santos A, Jorge P, Carreira LM. A randomized double-blinded controlled trial on the effects of photobiomodulation therapy in dogs with osteoarthritis. American Journal of Veterinary Research. 2022;83(8).
  12. Cachon T, Frykman O, Innes JF, et al. COAST Development Group's international consensus guidelines for the treatment of canine osteoarthritis. Frontiers in Veterinary Science. 2023;10:1137888.
  13. Gruen ME, Lascelles BDX, Colleran E, et al. 2022 AAHA pain management guidelines for dogs and cats. Journal of the American Animal Hospital Association. 2022;58(2):55–76.
  14. Bruno E, Canal S, Antonucci M, et al. Perilesional photobiomodulation therapy and physical rehabilitation in post-operative recovery of dogs surgically treated for thoracolumbar disk extrusion. BMC Veterinary Research. 2020;16(1):120.
  15. Turgut F, Yanmaz LE, Ates MY. Adjunctive low-level laser therapy improves gingival inflammatory clinical indices, thermographic findings, and systemic cytokines in cats with American Veterinary Dental College stage 1 to 2 periodontal disease. American Journal of Veterinary Research. 2026;87(5).
  16. Pluim M, Heier A, Plomp S, 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.
  17. Haussler KK, Manchon PT, Donnell JR, et al. Effects of low-level laser therapy and chiropractic care on back pain in Quarter Horses. Journal of Equine Veterinary Science. 2020;86:102891.
  18. Pluim M, Reynolds A, McClure S. Adjunct therapies for tendon/ligament healing: therapeutic laser and extracorporeal shockwave therapy. Veterinary Clinics of North America: Equine Practice. 2025;41(2):391–401.
  19. Cotler HB, Chow RT, Hamblin MR, et al. The use of low level laser therapy (LLLT) for musculoskeletal pain. MOJ Orthopedics & Rheumatology. 2015;2(5):00068.
  20. Hochman-Elam LN, Heidel RE, Shmalberg JW. Effects of laser power, wavelength, coat length, and coat color on tissue penetration using photobiomodulation in healthy dogs. Canadian Journal of Veterinary Research. 2020;84(2):131–137.
  21. Barale L, Monticelli P, Raviola M, et al. Preliminary clinical experience of low-level laser therapy for the treatment of canine osteoarthritis-associated pain: a retrospective investigation on 17 dogs. Open Veterinary Journal. 2020;10(1):116–119.
  22. Duarte D, Alves JC. Evaluation of the effect of photobiomodulation on joint range of motion in dogs. Lasers in Medical Science. 2025;40(1):296.
  23. Wardlaw JL, Gazzola KM, Wagoner A, et al. Laser therapy for incision healing in 9 dogs. Frontiers in Veterinary Science. 2018;5:349.

This article is general information, not veterinary advice. Speak to your vet before starting any supplement or treatment, and ask a qualified animal physiotherapist to assess your animal individually.