Noticeable difference over night from just one application. I apply it after my toner but before my serum (after waiting for it to dry of course). In the morning there is much less redness, pain and swelling and if I use a second night in a row its pretty much gone, just slight redness remaining.
It is strong and can sting, but that's to be expected of a product like this. I have bought some for my man too and he's been impressed. I hope Clinique don't discontinue this any time soon because its the only one I've found that hasn't given my sensitive skin chemical burns or caused any issues.