What is the source of Collagen?

That is a big ask! there are around 1000 types recognised, and so many different cells in the body construct differing protein glue, most of which are a triple helix fibers that interlock tightly providing strong connective bonds, all come from cells that are provided nutrients from our blood plasma, they are unlike other proteins in that they do not have amino acids.

Extensively boiled beef bones provide a broth rich in hydrolized collagens of many types, these cannot directly be used as collagen when taken as food but contains the nutrients that would be helpful in constructing new collagen! also it is helpful to consume plenty of vitamin "C" if suffering lack of collagen!

But most of all sufferers need to reduce stress as in my opinion stress is the singular most prominent causal condition that effects everything from cold to cancer, all interconnected with our toxic environment and lastly (but not really lastly) our Spiritual condition v Sin!.