There are 3 categories of CBD usage: 

1. Topical. 
   Most topical uses include lotions, salves, balms, patches, or roll-on applications. Topical applications rely on the skin to absorb the hemp extract. 
2. Sublingual. 
   There are many different types of products in this category, but in this case they are all ingested. 
   Sublingual applications rely on the internal absorption of CBD and other cannabinoids into the bloodstream, then digestive system and from there, the liver metabolizes the oil molecules. 
3. Vaporization & Combustion.
   The inhalation of smoke or heated vapor relies on the lung tissue as a gateway to the bloodstream. 
   This is the quickest pathway for CBD and other cannabinoids to enter the bloodstream.