Derms Say This Serum Combines 2 of the Best Collagen-Stimulating Ingredients for Firming Your Complexion

Retinol and glycolic acid have long been positioned as skin-care world rivals. Both of these power-packed actives take on a different job in resurfacing your skin, but because of their intensity, we’ve long been conditioned to believe that they should not—under any circumstances—be used at the same time. With the launch of its new Even Smoother Glycolic Retinol Resurfacing Serum ($65), though, Peter Thomas Roth is proving otherwise.

Peter Thomas Roth Even Smoother™ Glycolic Retinol Resurfacing Serum — $65.00

The serum pairs the two ingredients in a way that allows them to work their magic in tandem. Glycolic acid works by melting away dead, dull skin cells, while retinol stimulates cell turnover to replace those dead cells with healthy new ones. Together, they work to smooth out the texture of your skin, diminishing fine lines, wrinkles, and discoloration in the process.

“Glycolic acid and retinol are two equally-useful, and science-backed ways to address multiple signs of skin aging,” says Rachel Nazarian, MD, a board-certified dermatologist based in New York City. “Combined they can make skin smoother, brighter, more even-toned, minimize wrinkles, and stimulate collagen.”

At this point, you’re probably wondering, “If they’re so great together, why have I always been told that I can’t use them at the same time?” According to Dr. Nazarian, the answer to this comes down to the fact that retinol and glycolic acid have the potential to be too powerful when combined at certain concentrations. “Given that some of their effects on the skin may be redundant, especially when it comes to decreasing oil production and stripping surface natural hydrators, the biggest risk of using both in your regimen is that you may cause excessive dryness, leading to irritation or inflammation,” she explains.

With the Even Smoother serum, Peter Thomas Roth has figured out a way to formulate the ingredients to ensure that (in most cases) these side effects won’t happen. “Retinol and glycolic acid are more tolerable when both ingredients are not actively working simultaneously,” explains Dr. Nazarian. “The PTR retinol appears to be time-released, which means that it slowly doses the retinol over the course of hours and not immediately after application.” This means that your skin will get a small amount of retinol throughout the day (instead of a giant hit of it all at once), which makes it safe to use alongside glycolic acid.

“The combination is also offset by calming and moisturizing ingredients such as hyaluronic acid and allantoin, which strengthen the skin barrier, shielding from possible dryness and irritation,” adds Dr. Nazarian. This, in effect, will help to stave off any potential irritation the more aggressive ingredients would usually cause.

That said, the formula still may not be A-okay for everyone. “Although this does improve tolerability to some degree, the use of both ingredients in a daily regimen may still be too aggressive for some sensitive skin types,” says Dr. Nazarian. She recommends testing it out once or twice a week to start, then building up to nightly use as your skin’s tolerability increases.

Considering this single product packs two of the best anti-aging ingredients on the market into one, it’s a worthy purchase for anyone looking for a minimalist routine with maximal impact.

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