The basis of light therapy in acne treatment is built on killing the acne-causing bacteria. The problem is that the UV light used in the therapy clears up acne; however, it may damage the skin and cause cancer. Today, doctors don't use UV light to treat acne. Instead, they use certain wavelengths of blue or red light to achieve the same purpose.
Some people have got very good results from this technique but the others still need to do many sessions to solve the problem. it depends on the type and the cause of acne.
According to a review of three studies, light therapy can improve the quality of life for patients diagnosed with acne. Light therapy is considered safe and effective against the symptoms of mild to moderate inflammatory acne. These treatments can be performed in-office or with at-home light therapy devices. Blue LED light therapy may destroy acne-causing bacteria (P. acnes)