If you've delved into the mysterious world of vaping you've probably already heard the terms PG and VG. You might not know what they are though, and how they contribute to the vaping experience. If you're already a professional cloud chaser then I'm preaching to the choir, but for the rest of you, listen up!
PG
The term PG refers to the substance propylene glycol. PG is an organic compound, and has several uses outside of vaping. It can be found in asthma inhalers, medical products and beauty products, such as make-up, shampoo and baby wipes. It is also used in various edible items such as coffee-based drinks, sweeteners, ice cream and fizzy drinks.
VG
VG is otherwise known as vegetable glycerin, and is a natural substance derived from vegetable oil. It's a thick, colourless and odourless liquid, with a sweet taste. VG is thicker than PG and gives a much smoother hit. In terms of real-world applications, VG is used in a wide range of food, medical and personal care products including make-up, aftershave, pet food, soap and hand cream, toothpaste and as a sweetener in various foods.
The Differences
There are a few main differences between the two substances, but together they form the basis for nearly all e-liquids. The ratio of the two varies based on personal preference, since it has an effect on the final vaping experience. PG is noted for its 'throat hit', which gives a sensation somewhat similar to smoking tobacco. This makes it desirable for heavier cigarette smokers who may be used to the feeling. It also carries flavour well, allowing you to properly taste a wide range of complex flavour combinations.
VG gives a smoother sensation when vaped, so if a throat hit isn't a priority it's a great alternative. Another thing VG is noted for is that it creates large vapour clouds, so the higher the percentage of VG in your e-liquid, the bigger these will be. Some vapers, known as cloud chasers, have taken this to competitive levels and try and create the largest clouds possible through modified equipment and high VG e-juice. This performance comes at a price, though, as the thick VG can make cleaning your equipment difficult.
PG
VG
More of a throat hit
Smooth throat hit
Smaller clouds
Huge clouds
Better flavours
Muted flavours
Easy on your equipment
Can clog up equipment
Are They Safe?
This is hard to answer definitively, but common sense should tell us that PG and VG are much preferable to the toxins from cigarettes/cigarette smoke. If you don't believe me, do you believe the Royal College of Physicians? Common side effects can include dry mouth, dry skin and itchiness (symptoms of dehydration) and possible allergies to PG that can cause irritation, but these allergies are rare, and much more preferable to cancer, heart disease and emphysema (some of the possible side effects of smoking).