Purifying human derived collagen from human tissue includes treating harvested human tissue with an enzyme to form a collagen product, deactivating the enzyme with a non-alkaline enzyme deactivation solution, and collecting the collagen product resulting from the enzyme treatment, where the collected collagen product includes a preserved amount of its natural collagen constituents. Various medical implants can be formed using the isolated, enzymatically-treated human derived collagen having an amount of its natural collagen constituents preserved, and may include implantable sponges, patches, tubes, structural supports and coatings, and which may be used for repair, barrier, support and/or stabilization purposes.