There are no robust studies for BPC157 fixing stomach issues, which are often physical, rather than chemical. I am pretty leery of these supplements, including intolerances and interactions with other drugs. Most people with MCTD are on prilosec or a similar drug. You can also look at Terry Wahls' protocol about mitochondrial issues and autoimmune. That is why many do adapt their diets, timing of meals and so on. My gastroenterologist was pretty good at diagnosing my issues, and for the rest it has come down to food choices. Keep a diary for a few weeks to note what you ate and drank as well as how you felt during the day. Also, there are good drugs for nausea. https://www.webmd.com/heartburn-gerd/triggers