I don't know if you are referring to supplements to coat the intestinal lining??? One supplement is slippery elm. There might be better supplements. I don't know, yet.
I haven't yet researched treatment for leaky gut syndrome. I want to read some books I ordered in the mail before I search the internet. Books usually have more extensive information. But I remember reading about slippery elm. I guess it helps produce mucus to coat the digestive tract.