Vitamin C

Vitamin C (ascorbic acid) is a water-soluble vitamin the body cannot make on its own, needed for collagen synthesis, antioxidant activity, and immune function.

Supplement

What it is

Vitamin C, also known as L-ascorbic acid, is a water-soluble vitamin naturally present in some foods, added to others, and available as a dietary supplement. Humans cannot synthesize it, so it is an essential dietary nutrient. It is required for the biosynthesis of collagen, L-carnitine, and certain neurotransmitters, functions as a physiological antioxidant, supports immune function, and improves the absorption of nonheme iron, the form of iron found in plant-based foods. Insufficient intake causes scurvy.

Food and timing considerations

The best food sources are fruits and vegetables, especially citrus fruits, red and green peppers, kiwifruit, broccoli, strawberries, and Brussels sprouts. Vitamin C is water-soluble and heat-sensitive, so cooking can reduce a food's vitamin C content.

Known interaction categories

Insufficient evidence
Monitor
Informational

Published interaction pages on this site

Sources

Vitamin C — Health Professional Fact Sheet — NIH Office of Dietary Supplements

Last reviewed 2026-08-24

Medical information disclaimer: this information is general and educational. It does not diagnose conditions, prescribe treatment, or determine whether a combination is safe for you personally. Follow your prescription label and ask a pharmacist or clinician before starting, stopping, or combining products. Full disclaimer.