The Recommended Dietary Allowance (RDA) for vitamins reflects how much of each vitamin most people should get each day. The best way to get the daily requirement of essential vitamins is to eat a balanced diet that contains a variety of foods. Here is the RDA for vitamin C, per the National Institutes of Health:
Children
• 1–3 years: 15 mg/day
• 4–8 years: 25 mg/day
• 9–13 years: 45 mg/day
Adolescents
• Girls 14–18 years: 65 mg/day
• Pregnant teens: 80 mg/day
• Breastfeeding teens: 115 mg/day
• Boys 14–18 years: 75 mg/day
Adults
• Men age 19 and older: 90 mg/day
• Women age 19 and older: 75 mg/day
• Pregnant women: 85 mg/day
• Breastfeeding women: 120 mg/day
Those who smoke need higher amounts of vitamin C. In all cases, ask your doctor what amount is best for you.
— Source: National Institutes of Health