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How does Laser Therapy Work?

Posted by Vitality Team on 2019 Aug 15th

For the purposes of this article we will be discussing Cold Laser Therapy or Low Level Laser Therapy (LLLT), as it is the type of laser commonly used by hands-on healthcare practitioners like Chiropractors, Physiotherapist, Massage Therapists, Veterinarians and many others.

How does Laser Therapy Work?

Photons enter the tissue and are absorbed in the mitochondria and at the cell membrane. The photonic energy is converted to chemical energy within the cell, in the form of ATP. Cell membrane permeability alters, then physiological changes occur. These physiological changes affect macrophages, fibroblasts, endothelial cells, mast cells, bradykinin and nerve conduction rates. The effects of Laser therapy are photochemical, not thermal.

Reported benefits include:

In layman's terms, therapeutic laser works much like photosynthesis in plants. Adding photonic energy to the body, helps it grow or repair itself.

Medical benefits include:

  • Rapid cell growth. Laser accelerates cellular reproduction and growth.
  • Faster wound healing. Laser stimulates fibroblast development in damaged tissue, reducing recovery time.
  • Increases metabolic activity through higher outputs of specific enzymes, greater oxygen and food particle loads on blood cells. Improves immune responses.
  • Reduces fibrous tissue, reducing the formation of scar tissue following injury or surgery.
  • Anti-inflammatory action for improved joint mobility.
  • Increases vascular activity. Laser stimulates lymph and blood circulation.
  • Lasers stimulate the process of nerve cell re-connection to bring numb areas back to life. Laser also increases the amplitude of action potentials to optimize muscle action.

  • Some common indications for Laser therapy are:

  • Wound Management
  • Soft Tissue Injuries
  • Inflammation
  • Joint Conditions
  • Arthritis
  • Chronic Pain
  • Dermatological Conditions
  • Myofascial Trigger Point Therapy
  • Acupuncture
  • Addictions - smoking or for weight loss

  • Contraindications for therapeutic laser:

    There are actually very few contraindications for laser therapy. They can be safely used around pacemakers and other implants, as metal does not absorb the photons. The exception however, would be for laser equipment that also emits a TENS like electrical stimulation.

    • Pregnancy - It is not recommended to use laser directly over the uterus. Research does suggest however, that therapeutic laser is safe at distant sites.
    • Epilepsy - Seizures can be created if the laser produces a visible red light that is pulsed between 5 - 10 Hz
    • Thyroid Gland - As the thyroid is a delicate structure, laser therapy is not recommended
    • Cancer - As therapeutic laser accelerates cell growth, is it not indicated for regions with potentially cancerous cells
    • Children - In regions with bone growth laser therapy should be used with caution. The research is incomplete as to potential side effects.
    • Skin abnormalities - Tattoos and skin discolorations will typically react differently to laser light and are often contraindicated

    Does it Hurt?

    No. Unlike hot lasers often used in esthetics for skin resurfacing or hair removal, the goal of therapeutic laser therapy is not to produce heat. Some patients experience some tingling or mild warmth but many do not feel anything at all. Other than a guide light or audible sounds from the device, you may not even notice that the laser is on.


    Dosage for therapeutic laser is measured in Joules. How long it takes you to deliver the dosage will depend on the laser you have. Therapeutic lasers currently in the Canadian market can deliver as much as 25 Joules per second to as little as 0.025 Joules per second. So for treatments delivering 400 Joules in total as an example, this represents a vast difference in treatments time from 16 seconds to 16,000 seconds (4.44 hours).

    There is a vast amount of existing and ongoing research on therapeutic laser and new protocols are being developed regularly. Typically however, it is recommended that you start patients with a more conservative dose and monitor their progress.

    If you are considering purchasing a therapeutic laser contact us at 800.461.0100 and we would be happy to provide you the estimated treatment times for most of the lasers in the Canadian market.

    Side effects

    Low Level Laser therapy is not known to have any long term side effects. Initial treatments may cause short term muscle spasm, mild fatigue, mild nausea or headaches. Safety goggles must be worn to protect against eye damage.


    Protocols for laser therapy will be found onboard on some equipment like that of the Zimmer 7 Watt Opton Pro.

    Zimmer 7 Watt Opton Pro

    For other devices you may need to refer to a treatment guide book. We have sample protocols for download titled “Light & Laser sample” in our listing for the Apollo 3 Watt desktop laser. This download provides sample protocols for typical conditions and addiction therapy.

    As Cold Laser Therapy is also commonly used on pets like dogs, cats and horses, we offer a treatment guide called Clinical Procedures for Veterinary Laser Therapy written by Dr. Curtis Turchin.