Comment by amavect

I just read through the study. I corroborate your summary.

> The tryptophan found in hydrolyzed whey binds to a different receptor than normal dietary tryptophan, thereby allowing your body to reuptake it and produce serotonin as usual. (This is all in the study.)

Took me a bit to find the quote.

> If tryptophan uptake was abrogated by poly(I:C) treatment, tryptophan supplementation should elevate serotonin levels even during viral inflammation. To corroborate this, we used a diet containing a glycine-tryptophan dipeptide, which bypasses the need for B0AT1 and enables tryptophan uptake via dipeptide transporters.33 This diet compensated for impaired uptake in poly(I:C)-treated mice and led to an increase in both tryptophan and serotonin levels in systemic circulation

Now I need to ensure that whey protein contains some glycyl-L-tryptophan. The study used a lab rat diet "TD.210749" (unsearchable, maybe a custom diet) from Envigo/Inotiv. The citation used pure glycyl-L-tryptophan "G0144" from TCI Europe (~$100/g haha nope).

I can't find anything on glycyl-L-tryptophan content in hydrolyzed whey (maybe you can help?), but found one on other tryptophan dipeptides, alanyl-tryptophan and tryptophanyl-tryptophan. The ACE receptor inhibition seems relevant, too. The PepT 1 protein appears to transport the dipeptides.

"Selective release of ACE-inhibiting tryptophan-containing dipeptides from food proteins by enzymatic hydrolysis" Diana Lunow et al. - https://doi.org/10.1007/s00217-013-2014-x

I'll try this out for my early waking insomnia, mildly reduced energy, and digestive problems (started after I got Covid, almost exactly 2 years ago). I need to find one without artificial sweeteners (hate the taste). I'll report back in exactly 2 weeks (sets calendar).