I used to get the flu every year and had a lot of injuries when I was younger. But I started taking a supplement called Beyond Tangy Tangerine. I've only been sick or injured once in the last five years and that was last month from a Colombiana. I've posted some details on this in a few threads. It's got vitamins, minerals, micro-nutrients, anti-oxidants, pro-biotics, enzymes, stuff for joints and probably more that I am missing. If you are in the US it costs about $300 for a year's supply. You need the powder, not the tablets, which have less in them. There's also a similar, but less complete, more geared for bodybuilders one called AnimalPak. If I'm at home I alternate between the two.
I don't know think there's anything that will protect you from girls' bacteria etc.
I don't know think there's anything that will protect you from girls' bacteria etc.