Lately, "delivery system" has become a major buzzword in the beauty world. Because basically, if your skin-care product doesn't have a good one, it's not going to work. “You can buy an $800 product, but if it’s not getting down there [into the dermis] it’s not going to be effective,” says Barbara Broas, national aesthetician for Le Métier de Beauté. “Many products just hit the surface of your face, but when you get deep down you’re going to actually correct what’s going on before it surfaces."Essentially, delivery systems are what gets the active ingredients in your skin care deep into the dermis, so that they can actually penetrate and work their magic. “An ingredient may be active in a test tube, but in the real world it needs to be applied to the skin without causing irritation, penetrate through the outer skin layer, and remain stable and active when it reaches its target,” explains Joshua Zeichner , MD, director of cosmetic and clinical research in dermatology at Mount Sinai Hospital. “Just as important as the active ingredient is the technology involved in stabilizing that active and allowing it to do its job in the skin.”We know this may be a little hard to wrap your head around, so if you're still a little fuzzy, Dr. Rocio Rivera, the director of scientific communications for L’Oréal Paris Skincare, breaks it down: “Think of the delivery system as a food-delivery service trying to deliver ice cream from Central Park to Union Square at 5 p.m. on a Monday," she says. "The vehicle (taxi, bus, motorcycle, subway) and route taken (FDR, Fifth Avenue) are all crucial to ensure proper arrival at the destination, but so is the temperature in the car so the ice cream is not liquid by the time it reaches (if it ever does) its destination. This is a very good example of how the vehicle and the conditions at which the active is delivered (temperature, pH, how much time does it take to arrive at the correct component of the skin) are key to ensure maximal efficacy.”The skin is designed to keep out everything, as its job is to protect our body from outside irritants, so this can make it tough for delivery systems. But there are a few efficient ones you can keep an eye out for. “Phospholipids, liposomes, microcapsules, and hydrogels are all different molecules that allow active ingredients to bypass the outermost layers of the skin to allow for better penetration,” says Elizabeth Tanzi, MD, founder and director of Capital Laser & Skin Care in Washington, D.C. “They have been used for years to increase penetration of both topical drugs and cosmetic products.”Scanning labels to try to figure out what really works when it comes to delivery systems can be tricky, so we did the work for you. Ahead, 10 products that really deliver.