What Is Collagen (and Do You Need More)?

It seems like every week there's a new beauty breakthrough, with a new miracle ingredient, that suddenly pops up in every supplement and cream on the shelves—from luxe to affordable skincare brands. You'll also find it in hair-thickening shampoos. And collagen has become the new ingredient du jour, with a whole slew of products promising more youthful, healthier skin, faster healing, and more.

But do collagen's benefits really live up to the hype? Here's what you need to know about collagen before you get started.

What is collagen?

Consider collagen a key building block for your body. "Collagen is a protein that is found everywhere in our body, in the skin, joints, tendons, ligaments, bones and connective tissue," says Erika Schwartz, MD, internist and founder of Evolved Science in New York City.

From a beauty standpoint, collagen is what helps maintain young-looking skin. Because visible signs of collagen lost first appear in the lips (as well as around the eyes), anti-aging lip serums are extremely popular. Likewise, products such as Revive Science's Collagen Eye Cream have become a shopper's favorite on Amazon. "While collagen is vital for our health, we typically think of collagen as it relates to our skin, and as we age production decreases," she says. "One of the first signs of aging of the face is a loss of volume and this is due to a decrease in collagen production." Skincare like retinol body lotions work to stimulate collagen. Collagen can also have a plumping effect on lashes so it can be found in some top mascaras. In popular volumizing drugstore shampoo OGX Thick & Full, collagen helps to hydrate hair.

What is collagen good for?

Scientists have been studying the benefits of collagen peptides for everything from type 2 diabetes to arthritis to burns, with some promising results. "Taking oral collagen peptides may provide some benefit to the health of joints and bones," says Dr. Schwartz.

As far as collagen benefits for aging skin, a few small studies have been published that show increased elasticity and firmness from supplementation—but most of those were funded by the supplement's manufacturers. And doctors have found those results a little dubious.

"Collagen and elastin are both important in maintaining youthful skin and are generally controlled by genetics," says Lindsey Bordone, MD, a dermatologist at Columbia University Irving Medical Center in New York City. "Taking collagen orally has not been shown to lead to increased improvement in skin appearance."

That's because you can't direct where that collagen you're taking goes in your body. "Most collagen supplements get digested in the intestinal tract or stomach and they do not even get to the areas of the body where collagen production occurs, making them useless," Dr. Schwartz says. "They only provide protein to our body as a nutritional byproduct."

Dr. Schwartz says topical collagen treatments might be a better solution for helping boost aging skin. "Creams used in aesthetics may be a bit more effective if they contain a binding agent such as hyaluronic acid or vitamin C or retinol," she says. She recommends prescription-strength topical collagen peptides, such as GHK-Cu. Even drugstore body washes such as Olay's collagen-infused cleansing and firming formula can potentially yield more results than oral supplements.

Where does collagen come from?

The collagen in your body is built by you. "Collagen is something your body makes in the skin and other tissues of your body," Dr. Bordone says. "It helps provide structure throughout the body generally. Younger children make more, and sometimes different types of, collagen than older individuals."

Collagen is a dietary protein, so you'll find it in plenty of the foods you already eat—including organic bone broth, citrus fruits, blueberries, raspberries, garlic, dark leafy greens, and cashews. "These foods are good in general so eating more of them will provide improved nutrition and thus maintain a healthier, more youthful you," says Dr. Schwartz. So go ahead and add more of these to your diet—but don't expect miracles.

"People have been consuming collagen in food for generations," Dr. Bordone advises. "If additional collagen supplements were shown to improve appearance in any significant way, then they would hear many more dermatologists recommending them to patients."