There is no natural source of collagen from non-animal sources. By definition, collagen comes from animal tissue such as cartilage, egg shell membranes, etc. However, researchers have managed to grow collagen by adding human genes to genetically-modified microbes (yeast or bacteria). I would never consider, nor would I recommend, using lab-grown collagen if there are perfectly healthy and natural choices available. But if you’re vegan and animal welfare is your top priority, then lab-grown collagen might be your only choice.