Also studies conducted on animals (especially primates) that cannot synthesize vit-c on their own, show that they intake about upto 80x the RDA value of vitamin-c. So, humans intake as low as 1.25% of vit-c levels that monkeys eat. https://en.wikipedia.org/wiki/Vitamin_C#Daily_requirements
Most often than not, RDA values are a joke and should be treated as bare minimum levels to prevent diseases such as scurvy and not as the optimum level. Sub-clinical deficiency in essential vitamins and minerals always happen.
Do you also have any comprehensive resources that explains if vit-c supplements can affect recovery from lifting weights or general exercise?
There isn't any that I am aware of except bowel tolerance method. IMO, timing during healthy state is relaxed - twice per day is probably enough for most people; during stress however individual dose shouldn't be higher but should be taken more frequently (until bowel starts to complain, which means C is not absorbed any more and passes to colon where it causes diarrhea trough osmosis). What is remarkable here is the difference between bowel tolerance in healthy (low) and disease (high) state which suggests that vitamin C absorption increases.
See my answer here: http://www.paleohacks.com/vitamins/vitamin-c-supplementation...
> Also what form of supplement & which brand did you intake? Liposomal vit-c?
I take pure synthetic AA with sodium bicarbonate half of the time (3-5g x2). I don't have experience with liposomal vit-c but I am sure it is way better then regular C, altho far more expensive.
> Do you also have any comprehensive resources that explains if vit-c supplements can affect recovery from lifting weights or general exercise?
I don't have one at hand now. Some people think it prevents adaptation during exercise and don't take it. I personaly think it reduces stress so it simply gives you an option to work more. Since exercise can actually reduce your immune system if you overdo it or have concurrent stressor, AA intake will certainly be more beneficial on the long run then any supposed adaptation shortcomings.
The claim it is not supported by mainstream medicine is nonsence. Like I said its not investigated. Only small doses are.
I'm not aware of evidence that this is true for megadoses (e.g. 10g per day, as you mentioned).
Given that you are making a claim not supported by mainstream medical consensus (that megadoses of vitamin C have positive health effects), you are essentially arguing that megadoses of Vitamin C have a different effect than regular doses. Given that you admit that megadoses have a different effect to regular doses, what is your evidence that megadoses have no side effects?