The efficacy and tolerability of 5-aminolevulinic acid 5% thermosetting gel photodynamic therapy (PDT) in the treatment of mild-to-moderate acne vulgaris. A two-center, prospective assessor-blinded, proof-of-concept study.

This proof-of-concept study supports the efficacy of 5% ALA thermosetting gel red-light PDT in inflammatory acne of the face with a relevant clinical improvement of inflammatory lesions with a very good tolerability profile. Clinical improvement was maintained in the medium term (Trial Registration Number: ISRCTN66066651).