It will make your skin look dewy and fresh, your bones and nails strong, and your joints pain-free. These are the claims made by the countless manufacturers of collagen supplements that come in the form of powders, pills and creams. For that reason, it’s no surprise that collagen has become a widely sought-after ingredient in the wellness and beauty communities. But collagen’s efficacy is still pretty up in the air. Frustrated? Here’s what we know.

What is collagen?

Collagen is one of the most abundant proteins in the body. In fact, collagen is “the main structural protein that forms the connective tissue throughout our body, from skin to bones, muscles, tendons and ligaments,” said Dr. Shari Marchbein, a board-certified dermatologist based in New York. It’s no wonder that the bottled up version of this protein (usually made of animal collagen) is in high demand.

Collagen makes up a whopping 80 percent of our skin, and works with another protein called elastin that — yes, you guessed it — keeps our skin elastic. But as we age, our bodies naturally start reducing collagen production. The board-certified dermatologist Dr. Whitney Bowe described our body’s collagen as “ropes of protein in the skin.” When we’re young, the rope remains tight, but as we age, the ends begin to fray. Essentially, our bodies are not able to replace the collagen we are losing as quickly as it is breaking down. Starting in our 20s, we begin losing about 1 percent of our collagen each year, said Dr. Bowe. This, unfortunately, means drier skin. Sun exposure, cigarette smoke and pollution can also accelerate collagen breakdown. “The concept of supplementing our collagen, especially as we age and as our body’s natural collagen production declines, is incredibly appealing from a dermatologic standpoint,” she said.