I know that there are varied opinions and test results, recommended dosage etc. regarding vitamin C. And I don't want to debate that. This is just my experience during 35 years of taking mega doses of vitamin C, and two of my findings. 1. Up until about 35 years ago, like most people, I would catch a cold 2 or 3 times a year. I found that a friend was taking 500mg of vitamin c daily as a prevention against colds. So I decided to give it a shot. For reasons I can't remember I started out taking 2 grams. But then after reading Linus Pauling's books and through experimentation over the next few years I found that taking 10 grams daily was the ideal dosage for me. So, the result is that I now catch a cold only once every 5 years or so. In fact, last year was the first one in about 10 years!! And when i do catch one the symptoms are significantly lighter than those of normal colds. 10 grams of vitamin c is the equivalent of that found a 400 lemons as I remember. I take the dosage in powder form, 3 times a day. 2. I get a physical once a year and my cholesterol is always a little high at around 220 to 230. So 3 years ago the doctor suggested an exam to check my arteries where they exam the artery in your neck with ultrasound(don't know what the exam is called in English).The result of that exam was that I have the arteries of a young person (I'm now 71). So I guess that significantly lowers my chances of having a stroke or heart attack. Given my eating habits, I was very pleasantly surprised to say the least. But at the time I just thought I had good DNA or something. It wasn't until recently that I read about many studies that have been done showing the benefits vitamin c has on protecting the arteries against the buildup of plaque and even of cleaning the arteries to some extent. When I was around 35 my cholesterol was over 300 and my triglyceride level was 5 times that of someone whose level is high. I took the necessary steps to return to a normal level, but if there was any buildup at that time, it's no longer there!! I know that there are claims that mega doses of vitamin c can prevent or cure everything from cancer to pimples. All I know is the above, and also that I have none of the problems so often seen in people my age, such as high blood pressure, diabetes, or anything else for that matter. Without the wrinkles you'd swear I was under 30!! If you are interested knowing more, you may find Linus Pauling's books of interest. Vitamin C and the Common Cold (1970), Vitamin C, the Common Cold and the Flu (1976), Vitamin C and Cancer (1979), and How to Feel Better and Live Longer (1986). However it was not these books that convinced me of the benefits of mega doses of vitamin C. It was my personal experience. Please keep in mind that most of the studies that claim that vitamin C does not prevent colds etc. are done using dosages of only 250mg to 1 gram. Hope you found this of interest.