Synopsis

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

Citrus bioflavonoids have a long history of traditional use in supporting immune health and managing symptoms of the common cold. These plant-derived compounds, found in citrus fruits like oranges, lemons, and grapefruits, are often included in dietary supplements marketed for cold relief. The rationale historically centers on their antioxidant and purported anti-inflammatory properties, as well as their ability to support the action of vitamin C—another popular remedy for colds. Traditional herbal and naturopathic systems have used citrus extracts to bolster general immunity and reduce the severity or duration of colds. However, scientific evidence specifically linking citrus bioflavonoids to direct antiviral effects against cold viruses (such as rhinoviruses or coronaviruses) is limited. While some laboratory studies suggest that certain flavonoids may exhibit antiviral activity in vitro, clinical evidence in humans is sparse and inconclusive. Most clinical trials and reviews focus on vitamin C, with bioflavonoids often being secondary or supportive ingredients. Thus, while their use is justified by tradition and some plausible mechanisms (antioxidant, anti-inflammatory), robust scientific validation for their antiviral effect in treating colds is lacking. Overall, citrus bioflavonoids’ use in colds remains primarily traditional, supported by anecdotal and theoretical rationale rather than high-quality clinical evidence.

More about citrus bioflavonoids
More about Colds (antiviral)

Other ingredients used for Colds (antiviral)

Other health conditions supported by citrus bioflavonoids

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