I love DoTerra's OnGuard. I have used it time and time again to prevent colds/flus, to kill infections, and to build up immunity. This stuff does wonders! I highly recommend this product and basically any of DoTerra's essential oils.
I use doTERRA essential oils regularly and purchased ON GUARD for my niece who could not find any hand sanitizer. On hands with coconut oil. Use dilution in cleaners. Nebulize it.