Photodynamic therapy or PDT is a microdermabrasion procedure that begins with preparing your skin to absorb the photosensitizer (aminolerulnic acid or ALA). Next, the ALA is placed on the targeted area and left on for 30 minutes, typically. One of the advantages of ALA is that it is only necessary to apply it to the troubled areas of the skin. Finally a light source, or laser is used on the skin to activate the ALA.

The light sources damages or demolishes the tissues that have soaked up the ALA. In some cases, actinic keratoses can be treated by just one application. Since ALA concentrates in rapidly growing and malignant cells, ALA-PDT is being studied for the treatment of superficial basal and squamous cell skin cancer.

When acne is treated with ALA-PDT, the ALA is absorbed into the oil glands and hair follicles. When activated by the light or laser, the ALA damages the oil glands and reduces the acne bacteria. This treatment helps reduce, and in some cases completely remove, acne.