@atomeye I'm aware I'm x posting here. I do not produce enough insulin, and I am insulin sensitive.
I take PPI's for peptic ulcer disease, plus I've had GERD issues in the past. I take the most powerful slow release PPI available, Dexlansoprazole 60mg. It has made no difference to my blood sugars. I have been on these particular PPI's for 3 months now. I have in the past taken Lansoprazole and Omeprazole. They work, but I do feel mildly nauseated on them, and the nausea is unrelated to eating.
Long term usage can upset the balance of bacteria in the gut leading to dysbiosis. In the long term there is a small risk of SIBO (Small Intestinal Bacterial Overgrowth) and Clostridiodes or C. difficile, which is a severe infection of the colon. I have taken them on and off for years after suffering from bleeding peptic ulcers with no issues.
The only other small possible issue, after long term usage, is Type 2 DM. Which would translate to a reduction in insulin sensitivity - insulin resistance for T1DM. This hasn't happened to me. I'm thinking that for someone on insulin therapy it may mean having to increase insulin dosing to compensate for the decreased insulin sensitivity. I must stress this has not happened to me. And PPI usage has not increased my C- Peptides which are low to normal. I hope that helps.