You really can never know for sure, vitamin C or whatever. Many many drugs are used in mainstream medicine without clear proof or mechanism of action. If you h

You really can never know for sure, vitamin C or whatever. Many many drugs are used in mainstream medicine without clear proof or mechanism of action. If you have a real problem to solve effort and money may be irrelevant. It was for me. I had 5 times a year common cold up until i did vit C thing.