Short version: red light can help the inflammation and redness side of acne, while blue light is the one more studied for the acne-causing bacteria — which is why a lot of masks combine both.

It works gradually and it's complementary, not a cure. Use it on clean, dry skin (makeup and SPF block the light), be consistent, and give it several weeks. For moderate or severe acne — or if you're on prescription acne meds, some of which increase light sensitivity — check with a dermatologist first. Anyone here used it for breakouts? What device and routine worked?