I've been using this for over 12 months, working my usage up gently over that time.
I can now use this 4 nights a week. (I'm aiming for 7 eventually)
My skin is brighter, clearer with less congestion. I'm thrilled with my skin at the moment.
The reason I like this over the other 2 brands of retinol I've tried is the texture. It's a runny milky serum that sinks in quickly and plays nicely with other creams. I usually lit it sink in on its own for half an hour and top with my night cream.