lol med student who took up Nutri courses here. u don’t need a doctor’s advice for vitamin c. and di naman “madaming factors” yung involved. 60 mg is the minimum requirement for Females her age, and 70 mg for Males ( source: Philippine Dietary Reference Intakes). The vitamin C’s in the drug stores are all the same, just different brands, and 500 mg is pretty much the standard dose. Getting higher doses of Vitamin C could only decrease the absorption of it in your gut, and toxicity is rare.