i would not take mega doses of anything. first, your body only needs a small amt at a time of vitamin c. all the excess puts extra work on your kidneys to get rid of, and it's all going down the toilet, essentially you wasting your money. it would be best to take a more natural form of vitamin c instead of the synthetic.
i like pure radiance's vitamin c because they have camu camu in it. i read somewhere, but not exactly positive that if you take in too much vitamin c, it will have a reverse effect and kick start the free radical process which isn't good. you might want to research that.