I think it’s worth a shot, yeah.

This has been found to be effective, although it has a huge list of potential side effects [0]. Anecdotally, among people with GI problems, especially IBS, it can often cause reactions such as nausea, anxiety, and bloating (some practitioners estimate this to occur in about 30% of patients). For this reason it is often recommended to start in small doses (3-5g), sometimes split throughout the day, and gradually increase up to the 30g target over the course of several weeks. Given the list of side effects, including less common but potentially serious ones, it is very much worth running this by your healthcare professional prior to use.

Although there is less research into it than l-glutamine, there is rapidly growing interest into the effects of creatine supplementation on dysfunctions of the epithelial barrier (which would include intestinal permeability aka "leaky gut") [1]. The upshot is that it is an well studied supplement that is very well tolerated by almost everyone.

Zinc carnosine is another one that can be helpful, if tolerated. However it is believed that enteric-coated formulations are required to be effective (which may be hard to find) due to very high absorption rates and susceptibility to stomach acid prior to reaching the intestines [2].

[0] https://www.mayoclinic.org/drugs-supplements/glutamine-oral-...

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8145094/

[2] https://www.sciencedirect.com/science/article/pii/S221074012...

Betaine also has some interesting studies around mitigating intestinal permeability, among lots of other things.