Extra dose of vitamin C based on a daily supplementation shortens the common cold: a meta-analysis of 9 randomized controlled trials.  Ran L 2018 [70]  Adults and children9 RCTs  Vitamin C (4–8 g/day)administrated at the onset of cold  Reduced cold duration (MD = −0.56, p = 0.02). Relieved cold symptoms including chest pain (MD = −0.40, p = 0.03), fever (MD = −0.45, p = 0.009), and chills (MD = −0.36, p = 0.01).