Vitamin C: How Much Is Enough?

Vitamin C is a water-soluble vitamin involved in collagen synthesis, antioxidant defense, iron absorption and normal immune function.

What the evidence suggests

People who eat enough fruit and vegetables often meet their needs without supplements. High-dose vitamin C does not turn a normal immune system into a supercharged one, and large amounts may cause gastrointestinal discomfort.

How to use it in practice

Supplementation can be practical when dietary intake is low or when a healthcare professional has identified a need. More is not always better, especially when several fortified products are used together.

What to check on the label

• Check milligrams per serving and servings per day.
• Add vitamin C from multivitamins and other supplements before choosing a high-dose product.
• Avoid assuming that a larger number on the label equals a better result.

Safety and context

Very high intakes can cause diarrhea or stomach upset and may be inappropriate for people with certain kidney conditions.

This article is educational and is not a substitute for individual medical advice.