"Our line of beauty-specific products support the skin’s moisture, improving the elasticity, tone and vibrance,” promises Vital Proteins, which sells collagen powder.

Skin mostly consists of the protein collagen, which over time becomes fragmented, like a fraying rope. We also produce less of it as we age. The result: wrinkled and less-firm skin.

“Research has shown that if you improve your collagen, your skin will look better,” says Gary Fisher, professor of molecular dermatology at the University of Michigan.

So why not just eat collagen?

“It’s like a story from the Dark Ages,” says Marcel Nimni, emeritus professor at the Keck School of Medicine at the University of Southern California.  “If you want to be smart, eat brain. If you want courage, eat heart. If you want to be beautiful, eat collagen.”

But it’s not that simple.

“When we eat collagen, our gut breaks it down into amino acids, just like any other protein,” explains Nimni (who literally wrote the book on collagen). In other words, your body doesn’t shuttle intact collagen to your skin. Nor can you direct the amino acids from the collagen you eat to build more collagen in your skin.

“The issue is not that the skin is deficient in collagen’s building materials,” says Fisher. “It’s that the machinery to build collagen doesn’t work as well as we get older.”

What’s more, “there’s only one amino acid—hydroxyproline—in collagen that’s special,” says Nimni. That is, it’s found in only a few proteins, and it’s essential for giving collagen its strength.

“But we’ve known for 60 years that your body cannot use hydroxyproline from the diet to build collagen. The body has to make hydroxyproline on its own,” Nimni explains.

What about supplements that contain peptides: short chains of two or three amino acids? “Enzymes in the intestinal cells break peptides down into single amino acids,” says protein researcher Paul Moughan, of Massey University in New Zealand. “And that’s primarily what you will absorb.”

Nimni’s bottom line

“This idea of eating collagen to improve your skin’s appearance is the ultimate fallacy. People are wasting their money.”

Photos: tashka2000/fotolia.com, Vital Proteins.