Vitamin C Causing Higher Bg??

I have never found that Vit C affects my bg, but like you I have seen plenty of conflicting research making claims to that effect.

After several decades of on/off Vit C intake at varying doses, I switched to naturally sourced Vit C in smaller doses since those synthetic mega doses can cause their own problems including loose bowels and acid reflux - and I feel much better for it.

It has prompted me to look for naturally derived supplements wherever I can.

Regarding C's effect on bg, I would say that the reaction is likely to be personal and highly variable depending on dose and other health conditions. At the moment I have a few malabsorption issues following a stomach bug several months ago, so I am trying to tread a line between not throwing too many concentrated supplements into a struggling digestive tract, while ensuring adequate nutrition. The only way to find out if it is working is by periodic tests for deficiencies.