Dermatologist Shereene Idriss breaks down how retinoids work: retinol takes the longest route to activate skin cells, tretinoin the shortest. Retinal sits in the middle. A newer compound called HPR promises strong results with less irritation, challenging the idea that you have to choose between efficacy and comfort.
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There is a rule with retinoids that the stronger it is, the more it wrecks your skin, except one that seems to cheat it. And the reason is rather elegant. So retinol doesn't actually do anything the second that you put it on your skin. It is a vitamin A derivative that is trying to get into the control room. So imagine every single one of your skin cells has a control room, and inside that room there is a golden receptor known as the retinoid receptor that once you switch it on and off, you can make more collagen, you can speed up cell turnover, which slows down as we age, you can unclog if you have acne, and in my world, holy grail, you can fade pigmentation. But every single retinoid is trying to enter the same control room and flip those switches on and off, but they're taking different routes, and that's why there hasn't been much excitement in this world. Retinols take the long scenic route. They have to change first into retinal before they change into retinoic acid before they can do anything. So it's a very long journey, which is why it tends to be slower and gentler and beginner-friendly. Number 2 is retinols. Retinols bypass the first step completely and just become retinoic acid, so it gets there faster, but it's a little bit more irritating and why a lot of people cannot tolerate a retinol. Retinoic acid, also known as prescription tretinoin, doesn't bother with the journey at all. She's like, bitch, I'm already here. And so she walks into the building, into the control room, and she just starts flipping the switch immediately, which is also why it's the most effective, but also why you're probably left really red, inflamed, peely, and irritated. But here is where it gets super interesting. So for years, people have assumed that one must simply power through this irritation. It is the price you must pay if you want the effectiveness. And I've been against this my whole time ever, telling you guys consistency over intensity. And that is because it's probably not the whole story. The irritation from a retinoid doesn't come from the retinoid being a harsh chemical like an exfoliating acid. It comes from how strongly your retinoid activates the receptor, triggering inflammation and temporarily disrupting your skin barrier before your skin can fully adapt. Which brings us to the newer generation of retinoid on the market known as HPR—hydroxyphenylpyrrolin retinoate.
