Is HistaminX free from GMOs? Ceylon Keeslar November 25, 2020 23:49 Follow Testing verifies that HistaminX is free from GMO markers. Related articles Are there any warnings or side effects when using HistaminX? What are the ingredients in HistaminX sourced from? Does Histamine Block Plus contain GMOs? What is the purpose of each ingredient in HistaminX? How do I use HistaminX? Comments 0 comments Article is closed for comments.