Photodynamic therapy with ALA and red light damages sebaceous glands by causing a heat reaction.

“So photodnamic therapy is where you take a molecule like alpha aminovolonic acid ALA and you paint it on the skin and you let it incubate for about an hour and then you shine a red light onto the skin to activate it. And that chemical gets into the sebaceous glands and percolates down through the skin. And when you activate it, it causes a heat reaction and basically induces damage in that whole area that's picking up that medication. So you're basically causing the oil glands to shut down. You're taking away the nidis for the inflammatory acne.”