I was stunned as I read this month's Allure and found a plug from dermatologist Doris Day for propylene glycol (page 69). She remarked that it's a good humectant for sensitive skin.
Propylene glycol is a humectant. It makes the skin feel moist and soft, and it keeps your products from drying out. It's also a carrier in fragrance oils, a solvent, a de-icer used on airplanes, and an anti-freeze. It's ubiquitous. It's used in so many beauty products (cosmetics, skin care, toothpaste, deodorant, and more), you'll be amazed if you start reading labels. Unfortunately, it's bad for the environment (it depletes oxygen in surface water), and it can cause contact dermatitis when used in concentrations over 2% (and for some skin, even lower concentrations). The findings on the effects of propylene glycol have been published in respected medical journals.
The Material Safety Data Sheet for propylene glycol says it may be harmful by ingestion or skin absorption. Remember, that's at a very high concentration. Chronic exposure may cause gastrointestinal disturbances, nausea, headache, and vomiting, along with central nervous system depression. If you get it on your skin, wash with soap and water - the very premise of Dr. Day's recommendation for cleansers! Granted, full-strength, industrial propylene glycol isn't in your beauty products, but what strength is OK for daily application to your skin? We don't know.
I disagree with Paula Begoun, self-described Cosmetics Cop, on most of her product reviews. In her Cosmetic Ingredient Dictionary, she describes propylene glycol as harmless. Could that be because she uses propylene glycol in her products?
Why do so many beauty companies use it? It's cheap. Plain and simple - it's cheap. It's legal too. Many companies prefer to use it over better, but more expensive humectants, and they count on having uninformed customers. Chances are good that you've been using products containing propylene glycol for years. That doesn't necessarily make them good for you.
I read labels. When a product has a high concentration of propylene glycol (near the top of the ingredient list), I skip it and select something else. Remember, you can still buy cigarettes, but that doesn't make them good for you.
Photo courtesy of Dow, which believes that propylene glycol is non-irritating to skin and harmless to aquatic life. They sell it.