It's up to you. Vitamin C is very safe. I've known people who take 4000-8000 mg per day, but I think that's a little extreme. If you space the 1500 out over the day (a good idea no matter what dosage one takes)—say 500 mg w/ each meal—there shouldn't be any problems. The worst you might get is an acid stomach or heartburn. If that happens, back off a little. If it persists even on lower dosage, you might consider switching to Ester C, which is calcium based. I can't tolerate ascorbic acid at all (IBS) so I take Ester C (500-1000 mg/day) with no acid/stomach problems at all.

I think 1500/day is on the high side anyway; 500-1000 should be plenty—12 hrs apart if convenient, w/ breakfast & supper if not.

Doc