Animal Cold Laser Therapy

Animal cold laser therapy uses low-level laser or light-emitting diode light, applied to the skin over a joint, muscle, or wound, with the aim of supporting comfort and tissue recovery. Practitioners say it may assist with healing, though research is limited. It is now usually called photobiomodulation. The "cold" in the name means the light does not heat tissue enough to cut or burn, unlike surgical lasers. Devices differ widely in wavelength, power, and dose.

It is most often offered in veterinary clinics and rehabilitation practices, where a veterinarian or trained technician applies it to dogs, cats, and horses with conditions such as osteoarthritis, post-surgical recovery, and soft tissue strain. Owners are drawn to it because it is quiet, non-invasive, and usually needs only a calm animal and a few minutes. Treatment is usually a course of several sessions.

The evidence is promising but incomplete. Several small trials in dogs, mostly with osteoarthritis, report improvements, but dosing and design vary, and a systematic review of rehabilitation after cruciate ligament surgery found only one positive photobiomodulation study with low risk of bias and one negative study. A veterinarian must diagnose and clear a sick or injured animal first, and rules on who may use lasers on animals vary by place.

The field traces to 1967 in Budapest, Hungary, where physician Endre Mester was testing whether laser light could cause cancer in mice. He applied a low-power ruby laser at 694 nm and found that treated mice regrew shaved hair faster than untreated mice, an effect he called laser biostimulation. Accounts of the exact publication differ, with a Hungarian-language paper from 1967 and follow-up work in 1968 cited. Mester went on to study wound healing, and the work spread through Eastern Europe and Asia into physical therapy, where it became known by names such as low-level laser therapy and cold laser.

Veterinary use grew from the same research, and sources describe animal use beginning with Mester's mouse studies. Over recent decades clinics began to offer it for arthritis, wounds, and rehabilitation, and the field adopted the term photobiomodulation as devices using LEDs as well as lasers became common. Today it is delivered mainly by veterinarians and by veterinary technicians and rehabilitation therapists working under veterinary direction. Laser safety standards, device regulation, and rules on who may treat animals vary by state and country, and there is no single global training standard.