Polypropylene glycols are used as food-safe antifreezes, skin-conditioning agents, solvents and stabilizers for pharmaceutical products, and in polyester production. Polyproplene glycols are a group of chemicals that are clear, relatively thick liquids, made up of chained propylene oxide subunits.
Polypropylene glycols are used in a number of applications throughout the food, medical and cosmetic industries. For example, they are used in many medications to make the active ingredients more soluble in water. They are also used to stabilize vitamins.
In the cosmetics industry, they are used as moisturizers and skin conditioners and to disperse fragrance. They are also used to change the viscosity of liquids and gels, as mixing a solution with a polypropylene glycol makes it thinner. They can cause skin irritation in some people.
In the food industry, they are used as refrigerants, and sometimes even as food additives. This usage is controversial, but as of 2015, the Food & Drug Administration maintains that polypropylene glycols are safe for human consumption, within limits.