Propylene Glycol is one of the most important ingredients added to manufacture e-liquid. A combination of propylene glycol and vegetable glycerine is used to create optimum levels of vapour production, rich flavour and throat hit. Propylene glycol is used to dilute the nicotine solution and is mainly responsible for rich vapour production. While vegetable glycerine itself is known to be much safer than propylene glycol, there are a few benefits of PG that cannot be overlooked.
The safety surrounding the inhalation of vaporised PG has been the subject of several studies over the decades. Propylene glycol is commonly used as an air sanitizer and disinfectant. After years of research, it was found that PG was neither toxic nor carcinogenic and small amounts of consumption will not have any adverse effects on humans. Propylene glycol could also possess deterring properties against influenza, pneumonia and respiratory diseases.
As a potent disinfectant, PG is known to eliminate germs even in high concentrations. Although further tests are yet to confirm this, clinical studies carried out in New Zealand revealed that PG's disinfectant properties could actually have health benefits. Despite the undecided fate of electronic cigarettes, propylene glycol itself has been branded as a safe product by FDA.
Propylene glycol has several uses other than e-liquids and is most commonly used as a disinfectant in restaurants and hospitals. PG is also used in fog machines to create vapour, much like in an electronic cigarette. Propylene glycol is used as an additive for foods, intravenous medication and cosmetics. Its disinfecting properties are also useful in manufacturing anti-icing fluids and anti freeze for vehicles and airplanes.
Propylene glycol has very few side effects that include irritation to the skin and eyes when inhaled in larger quantities. Chances of such reactions are higher when exposed to pure solutions of PG. It was also noted in some cases that inhaling propylene glycol resulted in weight gain.

