I put this on at night and have visible results the next day. I had results the first time I used it, with no wait period. It is as effective for acne as the gentle retinol cream that I use, except that my skin doesn't seem sensitive in the morning. I will say that I do not have bad acne. I get occasional breakouts. But I had been hoping for something that could combat the acne bacteria without ruining the good bacteria that I feel helps me stave off acne in the first place. My skin is somewhat sensitive/dry so I usually cleanse with water, but alternate with retinol and glycolic acid to fend off acne and exfoliate. This fits easily into my paired-back skincare routine. I use it on days that I still want to fight acne, but don't want to do anything harsh to my skin. I use cerave moisturizing cream on top, because I don't think it has any actives that would interfere. That has been working great. Thanks Cassandra Bankson for the rec.