Comparison of red light and blue light therapies for mild-to-moderate acne vulgaris: A randomized controlled clinical study

Background: Red and blue light therapies are safe and effective treatments for mild-to-moderate acne vulgaris. However, very few previous studies have directly compared the characteristics of these two methods. Objective: To compare the efficacy and side effects of red light (RL) and blue light (BL) for acne vulgaris and to assess these two therapies in different types of lesions. Materials and Methods: A total of 28 subjects with mild-to-moderate acne vulgaris were randomized into the RL group or the BL group. Subjects in each group received different light treatments, and they were followed up regularly until 2 weeks after the last treatment. The improvement rates of different types of acne lesions were compared between the 2 groups, as well as the incidence of adverse reactions. Results: At the 2-week follow-up, the average improvement rate of total acne lesions was 36.2% in the RL group and 30.7% in the BL group (p > .05). The average improvement rate of inflammatory and non-inflammatory lesions was 51.5% and 17.3% in the RL group, compared with 26.4% and 10.0% in the BL group (all p > .05). Treatment-related adverse reactions were observed distinctly in the BL group. Conclusions: Red light and BL therapies have similar efficacy in mild-to-moderate acne vulgaris, especially for inflammatory lesions. RL had advantages with fewer adverse reactions compared with BL.