Here is some information on DGL studies from Astrid Pujari, M.D.”In terms of relevant studies, the two that I know of were published in the late 1960s and early 1970s. They were small, and didn’t meet the ideal criteria we now use for research studies. These scientists didn’t study heartburn specifically, but found that DGL helped to accelerate healing in people with ulcers.
While the data on DGL for heartburn is fairly skimpy, licorice has been safely eaten as a food, in reasonable amounts, for hundreds of years. Without the glycyrrhizin, the risk is even lower. Given that, it may be worth a try ”as long as your doctor agrees.”
This is very close to my experience. DGL is claimed to be a proven heartburn remedy by many web sites but there is very little ground for that.
For more information read entire article in Seattle Times.