The fact that Retin-A's become the go-to wrinkle fighter for dermatologists is a bit of an accident. When it first hit the market in the '80s, the prescription drug was introduced as a groundbreaking solution to clearing acne, shrinking pores, and regenerating skin, preventing clogging and eliminating blackheads and pimples. When patients started noticing additional positive side effects--fine lines disappearing, age spots lightening, sun damage lessening--it earned its well-deserved reputation as a miracle product. There were, of course, negative side effects, too: red, flaky, itchy skin so dry it cracked--a dealbreaker for some who decided wrinkles might not be the worst thing after all.Retinol, which, like Retin-A, is derived from vitamin A, is much less harsh on the skin but presents a different challenge: it's a "naturally unstable ingredient" according to Dallas-based esthetician Renee Rouleau. "Light and air break it down so that it loses its effectiveness if not packaged properly." As technology's improved, an increasing number of brands have started to release new, stable formulas, most of which provide shockingly similar results to Retin-A without the bad parts. "Retinol is one of the most striking anti-aging ingredients out there because it really does give you improvements within minutes," says famed dermatologist Dr. Dennis Gross. "It makes your skin look perky." An over-the-counter formula, usually packing anywhere from .05 up to 2 percent retinol, is especially beneficial to anyone in their 20s, a decade during which most people are still battling some form of acne while also developing fine lines.

Glow by Dr. Brandt's Overnight Resurfacing Serum ($85) boasts the most retinol allowed in a non-prescription product--2 percent--and astounding results. Though Rouleau says "it's not about the percentage, but about how stable the product is," we noticed results the next morning. Rouleau's own Advanced Resurfacing Serum ($83) may be a bit less potent (it has 1 percent retinol), but the formula is so gentle that our guinea pig, whose sensitive skin turns red from most moisturizers, is hooked on its brightening effects.

ROC Skincare and Skinceuticals hopped on the retinol bandwagon years ago, though both have refined their delivery systems and released new versions promising stronger results. The former's Retinol Correxion MAX Wrinkle Resurfacing System ($27) is a two-part deal, with a retinol cream followed by a resurfacing serum. One application is four times stronger than a series of three chemical peels and, as the name suggests, it does a bang-up job of fighting wrinkles--even crow's feet. Skinceuticals' Retinol 1.0 ($59) is more straightforward. Like all retinols, it turns over cells and builds collagen while shrinking pores and with just 1 percent retinol it strikes a balance between gentle and effective.

Dr. Gross, who released his Ferulic Acid & Retinol Brightening Serum ($85) in October, is a longtime fan of retinol. "I've tried all of the ones out there and I can tell you that retinol done right is a very powerful tool," he says. "It doesn't matter if you're in your 20s or 60s, it just makes your skin look better whatever your aging concerns." He added ferulic acid--an antioxidant that might have anti-carcinogenic properties and definitely aids with skin brightening--to his own product to protect against sun damage and enhance the retinol's effects. In case his enthusiasm isn't clear, Gross adds: "You need to use a retinol product."

-Britt Aboutaleb