I'm so used to Western products, I was expecting this to be a lot harsher, but the large amount of propolis has been doing wonderful things for my skin. The amount of glycolic acid in this toner is just right for me instead of over-exfoliating my skin horribly like the Makeup Artist's Choice Gly-Luronic serum I was using before. I've been using the A-Sol twice a day for over a week and it's noticeably reduced some of my acne flare-ups. it might not happen overnight, but I woke up this morning startled by how clear my skin looked. My PIH around my chin is drastically reduced. I hope COSRX never discontinue this one, I already have a backup on the way!