Thanks David, will read it. I recently read that sodium ascorbate was the best form of vitamin c, so now I'm confused?! I haven't ordered it as yet so I'll look into hydrogen ascorbate. I have a very sensitive stomach so when I took ascorbic acid I had a burning sensation in my tummy and then switched to low-acidity magnesium ascorbate. Maybe I can try this one, I do think vitamin c has helped me a lot, I get over colds in 48 hours with it!