A possible mechanism for visible light-induced skin rejuvenation

L. Longo, R. Lubart, H. Friedman, R. I. Lavie

Research output: Contribution to journalConference articlepeer-review

5 Scopus citations


In recent years there has been intensive research in the field of non-ablative skin rejuvenation. This comes as a response to the desire for a simple method of treating rhytids caused by aging, UV exposure and acne scars. In numerous studies intense visible light pulsed systems (20-30J/cm2) are used. The mechanism of action was supposed to be a selective heat induced denaturalization of dermal collagen that leads to subsequent reactive synthesis 1,2,3,4,5,6. In this study we suggest a different mechanism for photorejuvenation based on light induced Reactive Oxygen Species (ROS) formation. We irradiated collagen in-vitro with a broad band of visible light, 400-800 nm, 12-22J/cm2, and used the spin trapping coupled with electron paramagnetic resonance (EPR) spectroscopy to detect ROS. In vivo, we used dose 30 J in average (35 for acnis scars, 25 for wrinkles and redness. Irradiated collagen results in hydroxyl and methyl radicals formation. We propose, as a new concept, that visible light at the intensity used for skin rejuvenation, 20-30J/cm2, produces high amounts of ROS which destroy old collagen fibers encouraging the formation of new ones. On the other hand at inner depths of the skin, where the light intensity is much weaker, low amounts of ROS are formed which are well known to stimulate fibroblast proliferation.

Original languageEnglish
Article number27
Pages (from-to)158-164
Number of pages7
JournalProgress in Biomedical Optics and Imaging - Proceedings of SPIE
StatePublished - 2004
EventLaser Florence 2003: A Window on the Laser Medicine World - Florence, Italy
Duration: 6 Nov 20038 Nov 2003


  • Light rejuvenation effect
  • Non ablative laser
  • ROS


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