Ultrastructure and light microscope analysis of intact skin after a varying number of low level laser irradiations in mice.

What the authors concluded

Under these experimental conditions (20 J/cm2), three, six, and 10 laser applications provided photobiomodulation effect on intact epidermis and dermis of mice, strain HRS/J, without damage being revealed by electron microscopy. However, 10 laser applications decreased the type I collagen on the dermis. Thus, it is clear that more studies are needed to standardize the energy density and number of