What is the effect of low-level laser therapy (LLLT) or photobiomodulation (PBM) using red light?

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Last updated: April 28, 2025View editorial policy

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From the Guidelines

Red light therapy is conditionally recommended for the treatment of actinic keratosis (AK) due to its effectiveness in lesion reduction and complete clearance, as well as its relatively low risk of side effects, as supported by the most recent and highest quality study 1.

Key Points to Consider

  • The use of 5-aminolevulinic acid (ALA) as a photosensitizing agent with red light therapy has been shown to be effective in treating AK, with complete clearance rates ranging from 23.5% to 73.5% depending on the application time 1.
  • Longer ALA application times (1 hour to 4 hours) are favored over shorter application times to enhance complete clearance of AKs, based on low-quality evidence 1.
  • ALA-red light PDT has been compared to chemical peeling using 35% trichloroacetic acid, with PDT showing superior lesion reduction and complete clearance rates, but also higher treatment-associated pain 1.
  • Daylight PDT protocols using natural sunlight as the energy source have been shown to be equally effective as conventional red light PDT, but with significantly lower pain scores 1.

Treatment Recommendations

  • Typical treatment involves sessions of 10-20 minutes, 3-5 times per week, using devices that emit red light in the 630-660nm range or near-infrared light in the 810-850nm range.
  • For home use, FDA-cleared devices are available ranging from $100-500, while professional treatments at clinics cost $25-100 per session.
  • To use effectively, clean your skin before treatment, position yourself at the recommended distance from the device, protect your eyes with goggles, and be consistent with your treatment schedule.

Mechanism of Action

  • Red light therapy works by stimulating mitochondria in your cells, increasing ATP production and promoting cellular repair and regeneration.

Safety and Side Effects

  • Results typically take 4-12 weeks of regular use, and the therapy is generally considered safe with minimal side effects, though it's not recommended for those taking photosensitizing medications.
  • The incidence of local skin reactions during illumination was dose-dependent and ranged from 26% in the 0.5-hour group to 66% in the 4-hour group 1.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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