The fastest-acting skin-care ingredients can only be prescribed by dermatologists. Boo. Not fair. The reason? In a nutshell, once an ingredient has been shown to affect the structure or function of skin (yes, please!), it requires medical supervision.
But there’s good news, too: In many cases, you can get slightly weaker (and oftentimes, cheaper) versions of the exact same ingredients at the store. “They take longer to work, but if you use them consistently, they’ll also fade dark spots or reduce fine lines,” says New York City dermatologist Doris Day, MD. “And the advantage of over-the-counter versions is that they’re often combined with other synergistic anti-aging and soothing ingredients.” In other words, they’re easier for the skin to tolerate and you can use them for longer. Click ahead to find out what you need to know.