According to the Mayo Clinic, high doses of dietary vitamin C is unlikely to be harmful. And according to Oregon State’s Linus Pauling Institute, “There is no scientific evidence that large amounts of vitamin C (up to 10 grams per day in adults) exert any adverse or toxic effects. Super C Biotic supplies 951 mg of Vitamin C per serving, which is slightly less than 1 gram. 

Linus Pauling was a pioneering researcher of vitamin C who suggested an optimum daily intake of vitamin C may be about 2,000 milligrams per day, and that everyone should get at least 200 to 250 mg/day.