A cold laser is a low-powered therapeutic device that uses red or near-infrared light to reduce pain and inflammation without generating heat. Unlike surgical lasers that cut tissue, cold lasers produce photochemical reactions in cells, not thermal ones. The technique is also called low-level laser therapy (LLLT) or photobiomodulation, and it’s used by chiropractors, physical therapists, and pain specialists for a range of musculoskeletal conditions.
How Cold Lasers Work
Cold lasers emit a focused beam of light at specific wavelengths that penetrate the skin and interact with cells underneath. When the light reaches the energy-producing structures inside cells (mitochondria), it triggers a chain of chemical reactions that increase protein synthesis and cell metabolism. This process reduces inflammation, promotes new blood vessel growth, and encourages cell repair.
The key distinction from surgical or cosmetic lasers is power. Cold lasers operate at such low energy levels that they don’t heat tissue. You won’t feel burning or cutting during treatment. The “cold” in the name refers to this absence of thermal effect, not the temperature of the device itself.
Wavelengths and Tissue Depth
Cold lasers typically use two ranges of light. Wavelengths between 600 and 700 nanometers (visible red light, often around 660 nm) work well for superficial tissues like skin, wounds, and shallow joints. For deeper structures like muscles, tendons, and spinal joints, devices use near-infrared wavelengths between 780 and 950 nanometers. Near-infrared light is invisible to the eye and penetrates further into the body. Many clinical devices operate around 800 to 850 nm for this reason.
What Cold Lasers Treat
The most common use is pain reduction. Clinicians apply cold laser therapy to conditions including osteoarthritis (particularly knee pain), carpal tunnel syndrome, chronic neck and back pain, diabetic neuropathy, and tendon injuries. It’s also used for wound healing and tissue repair after surgery or injury.
A meta-analysis in Pain Physician Journal found that cold laser therapy produced significant improvements in patients with fibromyalgia across multiple measures: pain severity, number of tender points, fatigue, stiffness, depression, and anxiety all improved compared to placebo treatment. When combined with exercise, the benefits for pain and tender points were even more pronounced. Research also supports its use for non-specific low back pain and both acute and chronic neck pain, though results vary by condition and treatment parameters.
What a Session Feels Like
You won’t feel much. The practitioner holds a small handheld device against or near your skin at the treatment site. There’s no vibration, no heat, and no pain. Some people report a mild tingling sensation, but many feel nothing at all. You’ll wear protective eyewear because even low-level laser light can damage the retina with direct exposure.
Individual treatment spots take anywhere from 20 seconds to 5 minutes depending on the area and condition. A full session treating multiple points might last 10 to 20 minutes. The World Association for Laser Therapy recommends daily treatment for two weeks, or sessions every other day for three to four weeks, as a typical course. Some conditions require longer treatment plans.
Safety and Contraindications
Cold laser therapy has a strong safety profile when used correctly. There’s no recovery time, no medication interaction, and sessions are painless. That said, a few situations call for caution.
- Epilepsy: Pulsing visible red light in the 5 to 10 Hz range can trigger seizures. Devices that use flashing visible light should be used with extreme caution in people with epilepsy.
- Cancer: Treatment over active malignancies should only happen under the direction of an oncologist.
- Thyroid: Direct treatment over the thyroid gland is generally avoided. Rat studies have shown thyroid disorders developing after large doses of light radiation to that area.
- Pregnancy: Practitioners typically avoid applying large doses over the uterus, particularly in the first trimester, though treating other body regions is not considered risky.
- Growth plates in children: Some caution exists around treating over bone growth plates, though animal studies have not shown harmful effects on healthy growth plates.
One common misconception involves pacemakers. Cold lasers do not interfere with pacemakers because the devices are encased in metal that photons cannot penetrate. The only exception is a combination device that also delivers electrical stimulation.
FDA Classification
The FDA classifies lasers into hazard classes from I (lowest risk) to IV (highest risk). Most cold laser therapy devices fall into Class IIIb, which means they pose an immediate eye hazard if you look directly into the beam and a potential skin hazard from direct exposure. This is why protective eyewear is required during treatment. Class IV lasers, used in some newer “high-intensity” laser therapy devices, carry greater risks including burns and fire hazards, and technically cross the line from “cold” laser into a different category. Any laser product marketed for medical use in the United States must comply with both radiation safety standards and medical device regulations.
Cost and Insurance Coverage
Sessions typically cost $50 to $150 each when paying out of pocket. Many clinics offer package pricing that brings the per-session cost down: a 6-session package generally runs $240 to $600 ($40 to $100 per session), while a 12-session package ranges from $480 to $1,200.
Insurance coverage is inconsistent. Some private insurers, including plans like Blue Cross Blue Shield, cover cold laser therapy for chronic pain or injury recovery, but they usually require a doctor’s referral and documentation of medical necessity, such as pain lasting more than three months. When insurance does cover treatment, out-of-pocket costs can drop to $20 to $60 per session. Medicare offers limited coverage in certain approved chiropractic settings, with strict criteria. It’s worth calling your insurance provider before starting treatment to find out what your plan covers.