> Taking vitamin C by grams will give one a diarrhoea, and a pretty violent one.
Yes when your body gets enough of it (its called Vitamin C Flush and its not harmful), which is dynamic. I take 10+ grams and do not have diarrhoea, I might get it on 20+ IF I am healthy. I don't get it with 100g when I have influenza which is the state of the system when body requires more and SVCT pumps are active like crazy. This is trivially easy to check out yourself, you don't need a study. I have never seen a better feedback system for any drug, really.
> Can you explain and cite a study reference?
There are no studies about it, you need to try it yourself. Vitamin C is non-toxic and doesn't produce kidney stones, contrary to popular belief.
There are medical hypothesis and Linus Pauling wrote a few books about it long time ago.
> One of the common strategies to prolong the circulation of vitamin C is to recycle it by coupling it with, e.g. N-acetyl cysteine.
Yes, I take NAC too, however, the worst offender is sugar, as GLUT2 transports both C and glucose, and since its passive transporter C gets outcompeted given the levels of both.
I can explain 2 decades of experience with it, if you need some info send me a note.
One of the common strategies to prolong the circulation of vitamin C is to recycle it by coupling it with, e.g. N-acetyl cysteine.