I need a guide to go by regarding the amount or percent of essential oils necessary to ex: to kill a virus, to be antibacterial, etc... can you direct me to the appropriate website?

That's too vague. Can you be more specific?

Essential oils are of such varied compositions that I can't imagine any general way to predict a effective dose.

I was on the web and came across a compositional type page that showed all essential oils and there chemical constitutions. It broke down each specific oil and listed its percentage of say antibacterial effect and what percentage was necessary for the specific instance. Let me tell you what I am doing. I am using essential oils in products for say antibacterial cleaner... How much Tea tree oil for ex. Is necessary for this to be antibacterial in nature?

It sounds as if you have the source of information you need. If you want to claim your product has antibacterial activity and other health related uses, aren't you going to need FDA approval? Good luck!

I actually came across that site years ago and cannot find another!! Or what I would look under... I have tried everything!