Vitamin C

Studies in people

• Open question

  Common cold severity²

  Vitamin C may shorten and ease colds, but studies in people show mixed results.

• Benefit

  Stress hormone levels³

  In women with high stress hormones, vitamin C supplements lowered their cortisol and DHEA-S levels.

• Benefit

  Oxidative stress in women⁴

  In postmenopausal women, vitamin C lowered markers of oxidative stress and raised antioxidant capacity.

Study type not stated

• Benefit

  Immune defense⁵

  Vitamin C helps immune cells work and may help prevent and treat respiratory infections.

• Benefit

  Common cold symptoms⁶

  Vitamin C may shorten bad cold symptoms more than mild ones, though scientists are still studying this.

• Benefit

  Daily health and disease prevention⁷

  Vitamin C helps the body make collagen, absorb iron, and fight infections, but scientists still disagree about its power to prevent disease.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least two findings in people. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.