Although several light and laser therapies have FDA approval as medical devices to treat acne, no true photodynamic acne therapy, combining photosensitizer and light, has been approved.

WSJ: As More Adults Get Acne, New Photodynmic Treatments Use Light

More than 10 years ago, researchers at Massachusetts General Hospital in Boston and other centers discovered the compound aminolevulinic acid, or ALA, is a photosensitizer, meaning it is activated by certain wavelengths of light.

WSJ: As More Adults Get Acne, New Photodynmic Treatments Use Light