Vitamin C megadosage 6-8 g/day. As of 2014, at least 16 studies had found that vitamin C supplements did not prevent the common cold and had minimal effect at best in shortening cold lengths. Vitamin C megadosage Vitamin C megadosage is a term describing the consumption or injection of vitamin C (ascorbic acid) in doses well beyond the current Recommended Dietary Allowance of 90 mg/day, and often well beyond the Tolerable upper intake level of 2,000 mg/day. There is no scientific evidence that megadosage helps to cure or prevent cancer, the common cold, or a variety of other medical conditions. Historic advocates of
Vitamin K2 by this vitamin group were revealed to be much more complex. K vitamins play an essential role as cofactor for the enzyme γ-glutamyl carboxylase, which is involved in vitamin K-dependent carboxylation of the gla domain in "Gla proteins" (i.e., in conversion of peptide-bound glutamic acid (Glu) to γ-carboxy glutamic acid (Gla) in these proteins). Carboxylation of these vitamin K-dependent Gla-proteins, besides being essential for the function of the protein, is also an important vitamin recovery mechanism since it serves as a recycling pathway to recover vitamin K from its epoxide metabolite (KO) for reuse in carboxylation. Several human Gla-containing proteins