Retinol 0.5% in Squalane.

"You can probably afford to start with something maybe a little bit stronger like a 0.5 in squalane from The Ordinary. If it's just general anti-aging and a little bit more benefits of mild acne then you can use over the counter retinols. I think that's going to be quite nice. I wouldn't bother with any retinol esters and things like that because they're just too weak retinoids and they're not really going to change, especially doing skin cycling where you want something a little bit stronger because you're only going to be exposed to it for a short period of time."

"This can be a little bit more irritating than the 0.2%. If you've got oily skin, you might use the 0.5% rather than 0.2% because it won't irritate you as much. But if you've got irritated skin or a compromised skin barrier, repair that first and then start on 0.2%. If you've gone up the ladder, this is a great thing, but still be careful. Don't just start using this every day. Start using it alternately or even three days a week, and then week on week increase. If you've got very sensitive skin and want to start a higher strength retinol, use it once the first week, twice the second week, three times the third week, and so on. Eventually your skin will get used to it. If you get to a point where your skin doesn't get used to it, just stay using the retinol at three times a week. You still get benefit from it."