If you’ve ever tried retinol and had to abandon it— the peeling, the redness, the strict rule about not using it in the morning—you’re not alone. Retinol is, without question, one of the most well-studied skin care ingredients ever. The research behind it is robust, the results are real, and dermatologists have been recommending it for decades. But it also comes with a list of caveats that can make it genuinely difficult to use consistently.