I've been using this REN Bio Retinoid Serum for almost a month now and am loving it. I also have prescription retinol (tretinoin) but end up finding it too harsh in the wintertime. So I've been using the serum in lieu of it and am impressed. It has definitely left my skin feeling softer and less dull, and I've also seen a small improvement in fine lines (I'm 31 so trying to keep those at bay).
I like that it has niacinamide and ceramides, as these were ingredients I used in other serums in addition to my retinol previously. It sinks in pretty quickly and doesn't leave any greasy residue. I try to layer it under sunscreen when I use it in the AM. I also like that it's strong enough to see results, but gentle enough for daily use. Overall I'm a big fan and would definitely keep in my rotation.
