Let's start with what collagen is and why you definitely want it. Collagen is what makes your complexion firm, plump, and youthful. Sure, there's other important stuff in the mix, but this protein makes up 75 to 80 percent of your dermis. "Collagen fibers are like a bunch of sturdy, fat Roman columns placed close together, holding up the top layer of skin," says Dennis Gross, M.D., a dermatologist in New York City. "When you're young and healthy, the pillars are strong, straight, and plentiful, so skin looks smooth. And when you pinch your cheek, skin feels spongy and full." When skin is healthy, it repairs and makes new collagen. If everything is working as it should, then cellular collagen-making machines called fibroblasts churn out new collagen and your body produces enzymes that, like a microscopic wrecking crew, break down old or damaged collagen and carry it away, says Ronald Moy, M.D., a derm in Beverly Hills, California. The result: a collagen give-and-take that keeps skin looking smooth and young. But things like ultraviolet rays, smoking, pollution, stress, and other factors wreak havoc by producing free radicals in your skin. "Free radicals are like little arrows that poke holes in and break down collagen fibers, causing skin to thin," Gross explains. Even more bad news: Excessive sun exposure reduces fibroblasts' collagen factories, causing a flimsier, weaker collagen layer, and overstimulates the wrecking crew that then clears out healthy collagen. (It's not just the sun you should be scared of; pollution might be your skin's biggest enemy.) No matter how much sunscreen you wear, eventually these collagen-making cells lose steam. "When you're young, they make a lot of collagen, but they get worn down starting around age 35," Gross says. The enzymes that break down collagen, however, become overactive because of excess sun exposure and damage from years earlier. Then come wrinkles and sagging. Make an expression, and you usually create creases. When collagen is strong, your skin bounces right back. But if collagen is weak, repeated movements cause permanent creases. Skin doesn't have enough collagen to fill in the groove, so you see a line even when you're not squinting or furrowing, and it no longer has the same density to resist gravity, Gross says. 1. Start caring about your collagen now. When you're relatively young and fibroblasts are at their peak—before you see the effects of sun or other damage—is the best time to protect collagen against future damage and begin shoring up skin's collagen layer. "Once skin starts to thin and sag, it's much harder to correct," Moy says. But it's never too late to adopt healthy-skin habits. One way to do it, which you're probably already doing: exercise and eat well. "Anything that increases oxygenation and blood supply to collagen will make skin healthier," he says. Antioxidant-rich fruits and veggies, meanwhile, help protect collagen from the inside. 2. Use antioxidants and sunscreen as your collagen's bodyguards. It takes only two short exposures to UVA rays (two hours of strong sun over two days) to turn up the body's production of the collagen-degrading enzyme MMP1. Levels increase with additional exposures, according to University of Michigan researchers. On the other hand, fair-skinned people who ramped up their sunscreen use, applying it at least three to four times a week, showed no detectable signs of aging after four and a half years and had smoother skin (which in part indicates healthier collagen) compared with those who maintained usual, less-frequent sunscreen application, according to a study in the Annals of Internal Medicine of more than 900 Australians. Using a broad-spectrum SPF 30 or higher is a must. You'll also need antioxidants to neutralize damaging free radicals and extinguish inflammation. A few antioxidants pull double duty and stimulate collagen while protecting it. "Vitamin C is one key that fits into specific receptors on fibroblast cells, helping to turn them on," Gross says. The best serums combine vitamin C with vitamin E and ferulic acid, two antioxidants that boost vitamin C's power eight-fold, according to research. Copper peptides likewise can benefit skin as an antioxidant and collagen stimulator, says Ranella Hirsch, M.D., a derm in Boston. 3. Build collagen as you would a workout routine. HIIT, yoga, Pilates: They all work in different ways to help you reach one goal—to get fit. The same goes for collagen building. "You want to expose fibroblasts to multiple ingredients, each of which targets different receptors but all of which tell cells to produce more collagen," Gross says. Along with sunscreen and vitamin C, this is what else helps get your collagen in shape: Proven and Potent: Vitamin A Derivatives Prescription retinoic acid (like Retin-A) and OTC retinol may be old news at this point, but that's a good thing: It means they've withstood the test of time because they work, says Hirsch. (New trends, like venom beauty products, don't have as much cred.) Both retinoic acid and retinol "turn on" genes and cells involved in collagen production. They also help organize new and existing collagen, Hirsch says. A recent study found that a four-week treatment with .1 percent retinol increased levels of procollagen types 1 and 3 (the body's precursor to collagen) and reduced wrinkles after 12 weeks. Retinol and Retin-A can be irritating, so limit yourself to a pea-size drop for your entire face, starting only every other night, she says. Gentle Collagen Stimulators: Peptides and Growth Factors Both have science to back up their collagen-building, antiwrinkle claims. Peptides, for example, act as messengers, telling cells to ramp up collagen production. Growth factors stimulate fibroblasts and stem cells to encourage new cells and collagen. The advantage over vitamin A: Both are less irritating, but results may take longer or be more subtle, which is why many experts recommend doubling up—retinoids at night or every other night, peptides and growth factors in the morning or on the night you skipped vitamin A. (Or try supplying vitamins from the inside). 4. Try the newest collagen skin-care products. If collagen is the holy grail of healthy skin, ingredients that trigger its production are what unlock its power—and the search is on for the next best thing. These three newcomers show promise. DNA repair enzymes, which were initially developed to thwart skin cancer, also have the benefit of reducing collagen loss. When you fix skin's damaged DNA, it becomes thicker and tighter, Moy says. Signaling proteins from snails seem odd, yes, but lab research shows that the proteins, which are a type of growth factor, tell dormant stem cells to reproduce and grow into collagen-making fibroblasts. Collagen-building supplements, meanwhile, sound too good to be true, but new research on a specific, more easily absorbed collagen peptide is noteworthy. 5. What about a professional procedure? Pro procedures take collagen building to the next level. Topical treatments are effective and easy, but it can take months to see results. The alternative: in-office treatments. They're pricier, of course—one can cost $1,000 or more, and you may need three to five—but they work (almost) at the speed of, well, light. Gross utilizes V-beam and Gentlemax lasers simultaneously during his 3-D collagen treatment to target multiple fibroblast receptors, with little recovery time. Fractionated lasers, such as Fraxel, are another go-to, thanks to good results balanced with minimal downtime. They cause microscopic, controlled "injuries" in the collagen layer, which the body repairs by making, you guessed it, new collagen. Professional microneedling works in a similar, albeit lower-tech way; tiny puncture wounds on the surface of the skin jump-start the healing and collagen-building process, and also help collagen-building ingredients penetrate deeper, Moy says. Another option in the dermatologists' toolkit: injectable hyaluronic acid fillers, such as Juvéderm and Restylane. Research shows that along with plumping wrinkles from below, they have an effect on skin's own collagen-making cells. "Skin cells are smart. When you inject fillers, they think, 'OK, this is how skin is structured now, let's produce more collagen to keep up,'" Hirsch says. "It's subtle, but over time, patients often find they need to come in less frequently—every five months instead of every three, for example." The right pro treatment depends on your skin and other factors; talk to your derm about what's best.