Problem Solving Part 1: Can You Have Too Much of a ‘Good Thing’?

Veterinary Laser/PBM therapy is still very much in the Frontier Medicine category, so it is imperative that we, the Veterinary profession, as The Animal Advocates, maintain authority over how and where this therapy is used.

Veterinarians, when taking on new technologies such as Laser therapy, must remain healthily wary about linearly extracting & extrapolating data re dosimetry and frequency etc. from Human Laser therapy, straight across onto our Veterinary patients.

It has now been over 4 decades since cats were treated by Vets as small dogs or shrunken hairy little people. It has been over 3 decades since we as Vets considered all canine breeds the same re physiology & biochemistry & pharmacology. Yet, out on the road during a recent trip calling into Veterinary clinics to demonstrate our particular Laser machine, I heard time and time again, of non-Vets giving human field Laser treatment advice to other Veterinary Laser users, without any thought or knowledge of the inter and intra-species variations of our Veterinary patients.

Even though our Vets1laser users per se are not having the issues reported below-in order to protect PBM therapy from getting bad press and to protect our veterinary patients from insufficient or excessive exposure, we have written the following set of open posts to help Veterinary Laser users problem-solve issues the way Veterinarians should and would do.

 Trouble Shooting Cogitations

Part 1: Increasing the Treatment Session  Frequency to 3-4 times a day?  No!

We need to give the body time to respond to the cascade and chemical responses triggered within it by each Laser therapy session However, we now note a recent trend to move from every 24-48hrs to more frequent use, regardless of the species being treated, with recommendations to administer therapy every 6-8 hours in some presentations.

This is a cause for concern, akin to the incorrect belief, “Well if some works, then more must be better” and we all know that is not true. PBM may not be a primary chemical or a pharmaceutical drug, but for many PBMT is regarded as a ‘Drug-therapy Equivalent’.1,2 PBMT may not elicit the same side effects as a mainstream drug therapy but that does not mean we can abandon any concerns about potential, as yet unknown, side effects.

PBM modulates the ancient primordial photoacceptive1,2 properties of known powerful intra-body molecules to modulate metabolic and oxidative pathways and the cellular signalling responsible for the survival or death of a cell. What we don’t know is whether other photoacceptors are also in that area that can be affected by light therapy-perhaps adversely and so we inadvertently could target prokaryotic or neoplastic cells.

The toxicity risk of any given medicine is proportionate to the actual dose, both as a stand-alone dose and as a cumulative risk- and PBM/Laser therapy is no different.

Three major species concerns are that Birds have a high metabolism to start with. Adding in multiple PBMT  sessions in a short period of time has to carry some risk of overstimulating the bird’s metabolism. Cats are very vulnerable to oxidative stress.

Acutely severely ill or badly injured Dogs often go into a metabolic hold, whereby the body expresses a ‘low T3 syndrome’ to act to limit protein loss by decreasing metabolic rate during chronic or severe illness. Ramping up the metabolism, even focally, by the application of multiple Laser sessions in a 24-hour period may not be in any patient’s best interest.

More broadly, each laser session induces a reaction in the body: you need to give the body time to work on these, now intra-body, chemical/neuromodulation events. As a personal human user of Class IV laser, not all treatment sessions evoke the same post-treatment response. Sometimes the effect is immediate and ergogenic. Less often, but it does occur, there is a need to curl up and sleep or there can be on occasions, depending on the lesion, unpleasant but not distressing symptoms of mild muscle cramping before muscle relaxation or literally feeling the perfusion resetting back to normal in a limb. Sometimes, one can feel mildly nauseous post-therapy for some hours.  When those issues are occurring, the last thing one wants is anyone near them or requiring one to remain still and constrained even for another laser session. These issues settle within 24 hours. By then, one is either happy to have another treatment session or be so recovered as not to need a session.  I imagine many veterinary patients would have similar experiences. In fact, some owners do report the pet being less mobile for the first few sessions. This is explained to the owner as an encouraging sign that suggests that increasing blood flow and reperfusion are occurring in that area. Whilst that is true, we also don’t want a reperfusion injury issue situation wherein we have overwhelmed the body’s resources to deal with a sudden demand for toxin removal by over-treating with too many sessions of PBMT in a short space of time.

These newer treatment suggestions of every 6-8 hour application are not yet based on strong peer-reviewed studies. One has to ask if there is a dosage selection or technique or disease presentation variant contained within the proponent’s findings and hence their recommendations of multiple daily PBM sessions. If so, that recommendation-if truly based on unique operator technique or dosage – may not extrapolate to other users safely, but rather as an increased risk of adverse response. Whilst the consideration of the Arndt-Schulz Law, and Hueppe’s Rule suggests it is unlikely to overdose-that doesn’t negate the risk of over-treatment, thus triggering the Law of Unintended Consequences.

In my opinion, given the current state of knowledge, failing to wait for 24hrs between treatments, in all but the most agonising of pain patients, could induce avoidable distress, increase the risk of adverse responses and over time induce habituation. The existing treatment guidelines have stood the test of time and brought much respect to PBMT. If we intend to change what works, then there first has to be more in-depth evidence providing that the benefits outweigh the risks. Until then it remains that whilst, as a rule, lower dosage may not be of the most benefit, higher frequency of treatments in a shorter time frame is not automatically of greater benefit.

Traditional Treatment Frequency


Chronic :Every 48hrs x 6-12 treatments

Acute: Every 24hr-48hrs x 6-12 treatments

Improve by Four or do No More

Post-op: 1-2 Sessions ( Dental extractions wait 24hrs post op. Incisions/Dental scaling-Same day).


Gradual decrease to twice a week, then once a week


Monthly-Seasonal as patient dictates.


We hope the above is of help to all Veterinary Laser users.

At Vets1Laser, we are passionate about putting Veterinarians at the forefront of Laser /PBM therapy.

If you have any different experiences using Laser in cats, we would love to hear from you.

Contact Dr Aine at [email protected] to share and discuss any thoughts or knowledge on all things Laser.


  • Steering the multipotent mesenchymal cells towards an anti-inflammatory and osteogenic bias via Photobiomodulation therapy: How to kill two birds with one stone. Amaroli et al. 2022. Journal of Tissue Engineering; 13: 1–17 DOI: 10.1177/20417314221110192
  • The nuts and bolts of low-level laser (light) therapy. Hoon Chung et al 2012 Ann Biomed Eng ; (2):516-33.doi: 10.1007/s10439-011-0454-7.  PMCID: PMC3288797 DOI: 10.1007/s10439-011-

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