Durability of the improvement of collagen I and collagen III with the use of oral isotretinoin in the treatment of photoaging.

Low-dose ISO is effective in remodeling the extracellular matrix (ECM). This study found that the increase of collagen occurs through the augmentation of both collagen I and collagen III fibers. With originality, it was possible to verify the durability of these fibers for at least 12 weeks. This may be related to the decrease in MMP-9 expression verified at the end of the treatment and 12 weeks posttreatment.