About the Vitamin C:
The product in the link from Iherb uses calcium ascorbate. That is buffered Vitamin C just like sodium ascorbate.
Ah, I see, now You have ordered Ester-C. I did never understand what Ester-C does, but I thought it was about the absorbtion.
Well, what I wanted to say is this, if You are too sensitive for ascorbic acid and buffered C (calcium or sodium ascorbate), then You could try natural Vitamin C.
The plant with the highest Vitamin C is camu camu. http://www.iherb.com/Madre-Labs-Madre-C-Vitamin-C-6-35-oz-180-g/17628