I have been experimenting with topical skin absorption of fresh garlic oil/allicin to avoid first pass metabolism by the liver. Apparently Allicin is the garlic component that has the most antimicrobial action, but its metabolite has unknown or known less effectiveness? The allicin can be absorbed through the skin.,

CAUTION: topical garlic oil can cause a serious chemical burn so use extreme caution (small amounts distributed over wide skins areas?). A large amount applied to a small area can cause skin breakdown and needing surgical intervention. I found a medical case report about this very issue but as my account is new it won't let me post a link.