What's already known about this topic? Many light-based therapies have been tried for acne vulgaris, but their effectiveness and safety are unclear. In an Acne Priority Setting Partnership physical therapies for acne management was an area of interest for many people with acne. What does this study add? High-quality evidence on the use of light therapies for acne is lacking. There is moderate-quality evidence of the usefulness of methyl aminolaevulinate photodynamic therapy (red light) and low- or very-low-quality evidence on the usefulness of aminolaevulinic acid photodynamic therapy (blue light) as standard therapies for moderate-to-severe acne. Our review reinforces the need for standardized outcome measures, larger studies of better quality and adequate reporting of future studies. Plain language summary available online