LAUSR

There is an increasing demand for low-level light therapy devices for the treatment of dermatologic conditions, such as acne, hair loss, undesirable body hair, and skin aging. This study evaluated the safety and effectiveness of a novel hand-held low-level light therapy device with a 680 nm red laser diode and a 450 nm blue light-emitting diode for the treatment of mild-to-moderate acne. A prospective clinical study was conducted on 57 patients with mild-to-moderate acne and Fitzpatrick skin types II–IV. Treatments were self-administered by the patients at home daily for 4 weeks. Conventional treatment was restricted during the study period. The number of inflammatory and noninflammatory lesion counts, Investigator’s Global Assessment grade, patients’ self-assessment, and adverse events were measured every two weeks, and follow-ups were performed until four weeks after the final treatment. Moreover, we evaluated the bactericidal effect of low-level light therapy on Cutibacterium acnes, a causative agent of acne vulgaris, in vitro. The mean number of inflammatory acne lesions decreased statistically at weeks 4 ( ∗ ∗ ∗ p < 0.001 ) and 8 ( ∗ ∗ ∗ p < 0.001 ). The proportion of Investigator’s Global Assessment grade 3, indicating moderate acne severity, decreased significantly at the final visit. No severe adverse reactions were reported. Furthermore, there was a significant reduction in the viability of Cutibacterium acnes following low-level light therapy exposure in vitro. The results of this study demonstrate that this novel, hand-held, and low-level light therapy device are safe and effective for the treatment of inflammatory acne, with good adherence.