Vitamin C Dosage Guide
Recommended daily intake by age and gender — based on NIH Dietary Reference Intakes.
Our assessment
Based on FDA adverse event data, vitamin C has a generally well-tolerated safety profile when taken within recommended limits. The most important finding is that serious risks are primarily associated with specific medical conditions or very high doses, not with standard use. Data not available on total number of adverse event reports from the FDA data provided.
How it works
Think of vitamin C as a critical nutrient for immune function and tissue repair. While generally safe, understanding its side effects and upper limits is key to avoiding problems. The daily upper limits for vitamin C include intakes from all sources—food, beverages, and supplements FDA FAERS ↗.
Safety profile
Specific side effects from FDA data include diarrhea, nausea, and stomach cramps when taking too much vitamin C FDA FAERS ↗. In people with a condition called hemochromatosis, which causes the body to store too much iron, high doses of vitamin C could worsen iron overload and damage body tissues FDA FAERS ↗. Data not available on specific report counts for each side effect.
Our recommendation
Be cautious if you have hemochromatosis, as high doses of vitamin C could worsen iron overload and damage body tissues FDA FAERS ↗. Vitamin C can interact with certain medications, including chemotherapy agents, radiation therapy, statins, niacin, warfarin, and protease inhibitors FDA FAERS ↗. Stay within the recommended daily upper limits to avoid gastrointestinal side effects like diarrhea, nausea, and stomach cramps FDA FAERS ↗.
AI-assisted analysis. Data sourced from NIH ODS.
Understanding RDAs
Dietary Reference Intakes (DRIs) are a set of reference values used to plan and assess nutrient intakes of healthy people. They include:
- RDA (Recommended Dietary Allowance) — The average daily intake sufficient to meet the nutrient requirements of nearly all (97-98%) healthy individuals.
- AI (Adequate Intake) — Established when evidence is insufficient to develop an RDA. Based on observed nutrient intake by healthy people.
- UL (Tolerable Upper Intake Level) — The maximum daily intake unlikely to cause adverse health effects. Exceeding the UL increases the risk of toxicity.
Values vary by age, gender, and life stage (pregnancy, lactation).
Source: National Academies of Sciences, Engineering, and Medicine
Recommended Dietary Allowance
| Age | Male | Female | Pregnant | Lactating |
|---|---|---|---|---|
| 0-6 months* | 40 mg | 40 mg | ||
| 7-12 months* | 50 mg | 50 mg | ||
| 1-3 years | 15 mg | 15 mg | ||
| 4-8 years | 25 mg | 25 mg | ||
| 9-13 years | 45 mg | 45 mg | ||
| 14-18 years | 75 mg | 65 mg | 80 mg | 115 mg |
| 19+ years | 90 mg | 75 mg | 85 mg | 120 mg |
Source: National Academies of Sciences, Engineering, and Medicine
Deficiency
Vitamin C deficiency causes scurvy. Symptoms include fatigue, malaise, and inflammation of the gums. Smokers and people exposed to secondhand smoke are at increased risk.