Collagen is the most abundant protein in our bodies. It’s used to make all our connective tissues—including skin, bones, blood vessels, cartilage, ligaments, muscles, and tendons. That has led ...

Your body starts to make less collagen as you age, starting in your mid-20s. Poor diet can lower your levels, too. When your body doesn't make as much collagen, it can lead to things like: Wrinkles ...