What is propylene glycol?

Propylene glycol (PG) is a transparent and odourless chemical at room temperature that is used in many products including pharmaceuticals, food additives and cosmetics as a liquid that absorbs water. PG is used in many pharmaceutical products include common antibiotics, inhalers and nebulisers for over the last 50 years. Approval of propylene glycol is further supported by the ATSDR (Agency for Toxic Substances & Disease) which states on its website that PG is as a 'Generally Recognized as Safe' (GRAS) additive for foods and medications.