Hey ,

Tryptophan
Tryptophan could in my opinion go two ways. It is a precursor for serotonin, which is one of the important neurotransmitters in the gut. Tryptophan also is used for communication and regulation between microbes and can stimulate gut motility.

In cases of chronic inflammation, tryptophan can be used by the immune system to cause more inflammation (via something called ‘the kynurenine pathway’ and the production of quinolinic acid which is made from tryptophan). In this study about intestinal inflammation and depression, it is described how elevated gut inflammation lowers serotonin production in the gut.

Because gut inflammation is probably present, I personally think this isn’t the best choice.

Hydrolysed Collagen powder
Collagen has been shown to improve digestive issues. It breaks down in glycine and proline. Hydrolysed collagen can help repair the gut lining and improve digestive complaints. For example in this study from 2022, they gave otherwise healthy females 2x 10 grams of collagen powder per day. It improved their digestive symptoms.

That being said, some people experience diarrhea with collagen powder

I have seen animal studies in which glycine helped with gastric ulcers. Hard to tell if it will work on humans, but it is worth a try. Collagen is easy to break down, but it still needs stomach acid. 

If collagen doesn’t give some relief, you could try glycine powder. It is an amino acid, which means it is acidic, but it is a weak acid. Glycine is also an amino acid that is needed for bile production. It also might increase detoxification, so if you are going to try collagen (or glycine) go slow and easy in the beginning.

I hope this helps you to make your choices!