Collagen is a family of proteins that are actually the most abundant proteins in the animal kingdom. In fact, there are at least 28 kinds of collagen that we know of that exist in vertebrates (yes, us included), but types I, II, and III are the most common in the human body.
Collagen’s role in the body is vital: It helps make up the structure of our skin, bone, cartilage, and muscle, with the purpose of helping tissues be more elastic and withstand stretching (So, for example, it keeps skin looking young and supple).*
We actually make our own supply of collagen, via our cells’ fibroblasts (assuming they have the amino acids and other required nutritional building blocks they need). In fact, it’s made by our body throughout our lifetime, but as we noted, it also decreases with age, and your natural levels can also be reduced by environmental factors and stressors, such as sun exposure and high-sugar diets.
This is why people look to things like topicals, supplements, and—yes—their diet to support natural production levels of collagen.*