What are the active ingredients is Histamine Block derived from? Ceylon Keeslar October 31, 2019 17:15 Updated Follow Diamine oxidase is derived from porcine (pig) protein concentrate. Vitamin C is from non-GMO corn. Related articles What is the reasoning for each ingredient in this product? Does this product contain gluten, soy, or grains? What is HistaminX derived from? What are the possible interactions or side effects of using Histamine Block? Is the shellac in Histamine Block dangerous? Comments 0 comments Article is closed for comments.