VG (Vegetable Glycerine) and PG (Propylene Glycol) are both colourless liquids as the primary ingredients in vape e-juice.
Vegetable Glycerine or VG mainly helps to produce a more dense vapour and acts as a sweetener and thickener. Generally, The higher ratio of VG in e-juice leads to smoother and larger vape clouds.
Propylene Glycol, or PG, helps to provide intense throat hits. The higher ratio of PG in e-juice leads to stronger throat hits.
A balanced 50:50 ratio between VG and PG in e-liquid would create the most balanced flavours.