e-juice manufactured for Vaping contains 3 primary ingredients. Vegetable Glycerin, Propylene Glycol & Food Flavourings.

Vegetable Glycerin

Vegetable Glycerin (often referred to as VG) or glycerol, is a clear, odorless liquid produced from plant oils, typically palm oil, soy, or coconut oil. Palm and coconut oils are natural triglyceride mixtures; each triglyceride is composed of three fatty acids esterified with glycerin. Vegetable glycerin has a number of valuable applications that include cosmetic products, foods, and as a replacement for alcohol in herbal and botanical tinctures.


How is Vegetable Glycerin Made?

Vegetable glycerin is produced using an extraction process called hydrolysis. During hydrolysis, oils are placed under the combined force of pressure, temperature, and water. The ester bond breaks and causes the glycerin to split from fatty acids and be absorbed by water; at which point the resultant is further isolated by distillation to increase purity. Purified vegetable glycerin has a texture similar to an oil or syrup due to its organic molecular makeup, specifically, three hydroxyl groups.


The Benefits of Vegetable Glycerin?

Vegetable glycerin used in food applications is USP grade or over 99% pure and has a sweet taste. Vegetable glycerin metabolizes differently than sugar and is used in low carbohydrate foods for sweetness and moisture. Unlike sugar, glycerin does not contribute to tooth decay.

Many household products, including lotions, shampoo, and toothpaste, contain vegetable glycerin. Glycerin is added to these products because it is a humectant; a substance that attracts moisture to the skin. In the cosmetic world, this has two practical applications. First, glycerin leaves your skin hydrated. Glycerin soap, for example, is popular for that very reason. Second, for cosmetic products that deliver an active ingredient, a humectant can increase the solubility of the active ingredient, making it more easily absorbed by the skin. It is also used as filler in commercially prepared low-fat foods (e.g., cookies), and as a thickening agent in liqueurs. Glycerol and water are used to preserve certain types of plant leaves. Vegetable glycerin metabolizes differently than sugar and is used in low carbohydrate foods for sweetness and moisture. Unlike sugar, glycerin does not contribute to tooth decay.


Vegetable glycerin may be used as a solvent and substitute for alcohol when producing botanical and herbal extracts. This is advantageous for people who wish to avoid alcohol exposure.


Other Uses for Vegetable Glycerin

The safety of vegetable glycerin coupled with its functional properties has made it invaluable for various medical applications. The hydrating effect of glycerin makes it ideal as a topical remedy for burns. Glycerin is also used in the production of suppositories. A good source to look for is a USP grade, non-GMO, allergen free, kosher certified vegetable glycerin.


Propylene Glycol

Propylene glycol (often referred to as PG) is the third “product” in a chemical process beginning with propene, a byproduct of fossil fuel (oil refining and natural gas processing) and also found in nature as a byproduct of fermentation. Propene is converted to propylene oxide, a volatile compound used frequently in the creation process of polyurethane plastics (and to create propylene glycol). Propylene oxide is considered a “probable carcinogen.” Finally, through a hydrolyzation process (separating molecules by the addition of water), you get propylene glycol.

Propylene glycol is found in thousands of cosmetic products as well as a large number of processed foods products. Another place you will find it is in many medications, serving as a way to help your body absorb chemicals more efficiently. It’s also a common ingredient in electronic cigarettes, contributing to taste and “smoothness” of the smoke.

This liquid substance is fraught with inconsistencies in research, as well as many differing opinions on whether propylene glycol is a dangerous toxin or a mostly harmless compound. There is no hard and fast answer to that question, however — according to a fair amount of research, the effects of propylene glycol are rarely negative and generally associated with extremely large, intravenous dosage levels.

Propylene glycol is also used in various edible items such as coffee-based drinks, liquid sweeteners, ice cream, salad dressing, whipped dairy products and soda (and you never hear of people saying that Salad Dressing should be illegal).

src: https://www.globalhealingcenter.com/natural-health/what-is-vegetable-glycerin/
src: https://en.wikipedia.org/wiki/Propylene_glycol
src: https://draxe.com/propylene-glycol/
src: https://www.vaporfi.com/blog/propylene-glycol-products/
src: https://www.thedailymeal.com/news/common-foods-and-drinks-hiding-antifreeze-compound/103014