Vegetable glycerin (VG) is a very versatile ingredient. It has three main uses which include that of being a humectant, solvent and sweetener. As a humectant, it is used as an additive in the body care industry to retain moisture in the skin. It also provides skin-softening and soothing properties. Coming from all natural sources and being non-toxic, it is one of the most popular cosmetic additives used today. It is a clear, colorless and odorless liquid that is the consistency of a thick sweet-tasting syrup. Given this, it is also used in the food industry as a sweetener in many products. It is soluble in both water and alcohol.
Propylene glycol (PG) is a synthetic food additive that belongs to the same chemical group as alcohol. It is a colorless, odorless, slightly syrupy liquid that is a bit thicker than water. It has practically no taste. Additionally, it can dissolve some substances better than water and is also good at retaining moisture. This makes it very useful as a food additive, so it can be found in a wide variety of processed foods and drinks. The US and European food authorities have declared it as generally safe for use in foods.