HPPH is primarily used in photodynamic therapy (PDT) for the treatment of various cancers, including skin, esophageal, and lung cancers. It acts as a photosensitizer, which, when activated by light of a specific wavelength, produces reactive oxygen species that destroy cancer cells. This targeted approach minimizes damage to surrounding healthy tissues. Additionally, HPPH is being researched for its potential in diagnosing tumors through fluorescence imaging, aiding in precise localization and treatment planning. Its relatively low skin photosensitivity compared to other photosensitizers makes it a favorable option for patients undergoing PDT.