Serini SM, et al. - Authors assessed in a 2-centre, assessor-blinded, prospective, proof-of-concept study, the effectiveness, and tolerability of red-light (630 nm) photodynamic therapy (PDT) with a new 5-aminolevulinic acid (ALA) “low-dose” topical gel formulation (5%) in the treatment of inflammatory mild-to-moderate acne vulgaris (AV). Findings suggested 5% ALA thermosetting gel red-light PDT to be effective in inflammatory acne of the face with a relevant clinical improvement of inflammatory lesions with a very good tolerability profile. In the medium term, clinical improvement was maintained.