I've found that taking 3-5000mg/day for the first 2-3 days I have a cold seem to make them far less severe; just a running nose instead of full on sinus closure

I've found that taking 3-5000mg/day for the first 2-3 days I have a cold seem to make them far less severe; just a running nose instead of full on sinus closure. I don't know about shortening the duration, as colds only usually last 3-5 days. >Regular supplementation trials have shown that vitamin C reduces the duration of colds, but this was not replicated in the few therapeutic trials that have been carried out. Nevertheless, given the consistent effect of vitamin C on the duration and severity of colds in the regular supplementation studies, and the low cost and safety, it may be worthwhile for common cold patients to test on an individual basis whether therapeutic vitamin C is beneficial for them."