Ingredient Watch: Propylene Glycol

Today’s focus ingredient is Propylene Glycol (PG), a chemical found in a whole range of beauty products, including hair care, soaps, moisturisers, lipstick, anti-acne products, mascara, toothpaste, deodorant, perfume, mascara, as well as some foods.

Important Note: Let me just preface this post by saying I am not a dermatologist or medical professional. Within this and all past and future posts discussing beauty product ingredients, my aim is to collate and summarise information and present it in a way that is accessible and informative. I will always use the most reliable sources of information available to me, and attempt to present it in an honest and unbiased way. If you feel that any of my posts have incorrect information, or you believe there is something important to add, please don’t hesitate to let me know by leaving a comment or emailing me at theglowdown@gmail.com. It is important to me that I get it right.

What does it do: PG does a range of things. One of its main uses in beauty products is to help formulations maintain their consistency and stop them from separating.  Another is to chemically alter the structure of the skin, allowing other chemicals to penetrate deeper.

In food, it is most commonly used as an anti-freeze.

The Good: It maintains an even spread of ingredients and prevents insoluble ingredients, like oils, from separating. It can also improve the effectiveness of ingredients that need to be deeper into the skin.

The Bad: PG has been known to cause allergic reactions in some users, and exasperate conditions like eczema and other skin allergies.

Dangers: The dangers associated with PG are very controversial. There does not appear to be much agreement between professionals or the research as to how dangerous or toxic the chemical is. Once of the big concerns is that PG could be a cancer causing carcinogen. Studies conducted on animals using low doses of PG found no increase in the likelihood of cancer. I could not find any studies on the carcinogenic effects of PG in cosmetic products on humans.

Another concern is that PG can lead to organ damage. It has been linked with skin, liver and kidney damage, however, this has only been proven to be an issue with inhaled, injected or ingested doses of PG. A couple of studies identified a small toxic effect following regular topical applications of products with PG in them, and others found no such effects.

Some Considerations When Using: The use of PG is monitored and limited in most countries. Because of how unknown the toxicity of PG when used in beauty products is, I would definitely say any product containing it is one that you should always follow the directions for use for. It is also probably advisable to limit the number of products you use that include PG, and try to avoid products containing it that you are likely to use every day.

How To Find It On The Label: How PG is labelled will depend on your country and the manufacturer. Some common ways it is labelled are as Propylene Glycol; Methylethy Glycol; 1,2-Dihydroxypropane; 2-Hydroxypropanol; 1,2-Propanediol and Propane-1,2-Diol. In foods, it is commonly labelled as E1520 or E490. You can find a fairly comprehensive list of beauty products containing PG here.


If you haven't already, please check out my post on Salicylic Acid.