Ester-C or Regular Vitamin C?

What is the difference between ester-C and regular vit. C from ascorbic acid?

I am interested in the answer to this question too. Some of the vitamin C formulations they sell in health food stores is insanely expensive, and I’d like to know why it is 10x the price of regular old ascorbic acid.

I read somewhere that buying ester-c is pointless and that the regular will do just as good, plus its less expensive. At the end of the day, vitamin C is still going to be vitamin C, no matter what fancy form it is in.