Propylene GlycolThe more commonly used liquid of the two, propylene glycol (PG for short) produces a more pronounced throat hit. Some users have found their throats to be irritated after using a PG-based e-juice, with some even reporting allergic reactions.
PG adds a slightly sweet component to the overall flavor which allows complex flavors to not be overpowered by the chemical properties of PG. It is a thinner liquid which helps prevent residue buildup around the various mechanical parts of your vape.
Vegetable GlycerinUsed less often in e-juice, vegetable glycerin (VG for short) produces a smoother throat hit than PG. As a result of its smoother hit, many users have found their throats to be less irritated after vaping.
It has a higher viscosity than PG and a more pronounced sweetness as well. That sweet flavor can overpower an e-juice’s other flavors from time to time. Due to its thicker properties, VG will produce more vapor in each hit. That added thickness can also result in buildup around your vape’s mechanical parts, which may require cleaning more often.