I was actually going to post a similar question. I have literal liquid bowel movements for days If i dose any amount of vitamin C in the severel gram+ range and I think something I remember reading was that, If you cant tolerate vitamin C, its an issue with you. I remedied this quite easily (and all of my stomach issues) by supplementing betaine HCL + pepsin with meals and just after. (should contain protein every meal, pepsin helps digest protein).
So far testing this I'm able to tolerate an amount of vitamin C that would normally have bad results stomach wise.
If that is too long to read
- Maybe its low stomach acid, try supplementing betaine HCL + pepsin with meals.