Propylene glycol is a form of mineral oil used in a range of different products, including engine coolants, paints, snack foods, and water-based personal lubricants. It’s produced when yeast and carbohydrates ferment.
There are various grades of propylene glycol. Industrial PG, such as that used in engine coolants and paints, is very toxic. Pharmaceutical grade propylene glycol is far less concentrated. It’s used in food stuffs, personal lubricants, and drug products.
Propylene glycol is often known by the acronym PG.