Betaine HCL works.
It can restore acidity levels and cures indigestion. You can find this at most health stores included Vitamin Shoppe.
I recommend starting at 1-3 capsules per day with a meal. I’ve seen other people recommend 2-4 capsules with everymeal. Betaine HCL cured my bad indigestion but I have to note that high levels of Betaine HCL were giving me bad hay fever and sneezing (something that happens to me when I loose a large number of intestinal flora). I was taking 3-4 capsules with every meal (about 12 a day), this is TOO MUCH. It completely cured my indigestion but with the cost of BAD hay fever and sneezing all day.
I only take a capsule now when I need it (about 1 capsule every other day).
Start off with 1 per meal and go from there, I can not explain why it gave me such bad hay fever and sneezing but I suspect high levels of HCL acid was destroying a lot of my gut flora. I had to triple up on my pro-biotics for a few days and I was cured 100% from my hay fever.