Choi JH, et al. – The effectiveness of ablative fractional laser (FXL) pretreatment and/or sonophoresis for enhancing the penetration of 5–aminolevulinic acid (ALA) into human skin in vivo, were assessed and compared. Effective ALA penetration in human skin in vivo was noted via ablative CO₂ FXL pretreatment. Ablative CO₂ FXL alone possibly served as an ideal setting for ALA penetration, without sonophoresis setting pulse energy of 10 and 20 mJ with more than 60 min of ALA incubation time.