E-liquid is a mixture of varying amounts of about 4 different ingredients. Nicotine, PG (propylene glycol), VG (vegetable glycerin) and flavoring. Some liquids can have additional ingredients, but for the most part, these are the main ingredients to all e-liquid.
The amount of nicotine is dependent on the strength of nicotine in your e-liquid, but let's say it is around 10% nicotine. Somewhere around 10% of your e-liquid will be flavoring. That leaves 80% of the liquid in your bottle for fillers, which dilute the flavoring and the nicotine. This is where PG and VG come in, and depending on how you like your vape, that determines the percentage of PG and VG in your e-liquid.
Propylene Glycol (PG) is a much thinner tasteless liquid. PG produces more of a “throat hit” (TH) than VG does, which simulates the feel of smoking better.
PG also has a higher rate of sensitivity for some people, meaning that some people just can’t use PG in their vape.
The more % of PG, the thinner the e-juice.
Vegetable Glycerin (VG) is a thick, sweet liquid.
VG produces luscious clouds of vapor. VG also imparts a sweeter taste to your liquid.
Simplified, VG gives more vapor and is sweeter. The more % of VG, the thicker the e-juice.
So, 50%PG/50%VG is an equal mix of TH and vapor.