Safety of light emitting diode-red light on human skin: Two randomized controlled trials

Jared Jagdeo, Julie K. Nguyen, Derek Ho, Erica B. Wang, Evan Austin, Andrew Mamalis, Ramanjot Kaur, Ekaterina Kraeva, Joshua M. Schulman, Chin Shang Li, Samuel T. Hwang, Ted Wun, Emanual Maverakis, R. Rivkah Isseroff

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Therapeutic applications of light emitting diode-red light (LED-RL) are expanding, yet data on its clinical effects are lacking. Our goal was to evaluate the safety of high fluence LED-RL (≥160 J/cm2). In two phase I, single-blind, dose escalation, randomized controlled trials, healthy subjects received LED-RL or mock irradiation to the forearm thrice weekly for 3 weeks at fluences of 160-640 J/cm2 for all skin types (STARS 1, n = 60) and at 480-640 J/cm2 for non-Hispanic Caucasians (STARS 2, n = 55). The primary outcome was the incidence of adverse events (AEs). The maximum tolerated dose was the highest fluence that did not elicit predefined AEs. Dose-limiting AEs, including blistering and prolonged erythema, occurred at 480 J/cm2 in STARS 1 (n = 1) and 640 J/cm2 in STARS 2 (n = 2). AEs of transient erythema and hyperpigmentation were mild. No serious AEs occurred. We determined that LED-RL is safe up to 320 J/cm2 for skin of color and 480 J/cm2 for non-Hispanic Caucasian individuals. LED-RL may exert differential cutaneous effects depending on race and ethnicity, with darker skin being more photosensitive. These findings may guide future studies to evaluate the efficacy of LED-RL for the treatment of various diseases.

Original languageEnglish (US)
Article numbere201960014
JournalJournal of Biophotonics
StateAccepted/In press - Jan 1 2019


  • low-level light therapy
  • phototherapy
  • randomized controlled trial
  • skin pigmentation

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Engineering(all)
  • Physics and Astronomy(all)


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