Synopsis

Source of validity: Scientific
Rating (out of 5): 2

Vitamin C (ascorbic acid) has long been proposed as a supportive treatment for viral infections, particularly the common cold and influenza. The rationale for its use stems from its role as an antioxidant and its importance in immune cell function, such as enhancing the proliferation and function of lymphocytes and phagocytes. Early popularity was driven by the advocacy of Linus Pauling in the 1970s, which led to widespread use despite limited scientific validation at the time.

Scientific studies have since investigated Vitamin C's effect on viral infections, especially upper respiratory tract infections. Meta-analyses of randomized controlled trials show that routine supplementation with Vitamin C does not significantly reduce the incidence of colds in the general population, but may shorten the duration and severity of symptoms modestly. There is some evidence that individuals under extreme physical stress (e.g., marathon runners, soldiers in subarctic conditions) may experience a reduced risk of developing colds with supplementation.

For more serious viral infections (such as influenza or COVID-19), evidence is limited and inconsistent. Some small studies suggest potential benefit in hospitalized patients, but larger, high-quality trials are lacking. Overall, Vitamin C is not a cure for viral infections, but may offer modest symptomatic benefit, especially in populations at risk of deficiency.

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Other ingredients used for Infection (viral)

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