Is Propylene Glycol Dangerous?


Propylene Glycol is an organic alcohol found in a wide variety of cosmetics, fragrances, personal care products and even food. Once it is absorbed by the skin, this ingredient is metabolized into lactic acid, which is the substance that occurs naturally when muscles are exercised.

Still, this colorless and viscous liquid is getting a bad reputation as a toxic and dangerous ingredient that should be avoided at all costs. But what’s the truth? Is Propylene Glycol really as bad as some people make it out to be?

Why is Propylene Glycol used in beauty products?

Propylene Glycol is used in beauty products for several reasons. It is used to attract water from the environment to the skin, keeping it hydrated and moisturized, as a solvent to dissolve other substances, and to help active ingredients penetrate the skin better. In addition, Propylene Glycol helps the various ingredients used in products to combine, binding them together and keeps these products from freezing at low temperatures or from melting at high ones.

The controversy

A quick search around the web will bring up lots of websites claiming that Propylene Glycol is a very dangerous ingredient.They claim that it is an industrial antifreeze and that it is used in brake and hydraulic fluids. They also state that Propylene Glycol is very irritating and that, when it comes into contact with the skin, it can cause kidney and liver problems. Not only that, but according to the critics, it can cause cancer too! Scary stuff, huh? But is all that true?

The truth about Propylene Glycol

Well, there is some truth to these claims, but as it often happens, the truth has been twisted. Sometimes by people in good faith who didn’t dig into the matter deep enough, other times by natural companies that, to sell more of their products, claim all sort of nasty and dangerous stories about any synthetic ingredient. It is true that Propylene Glycol is used as an antifreeze, but at concentrations of 100%! And yes, such high concentrations can be very irritating and cause redness and stinging when they come into contact with the skin.

But the amount used in cosmetics and personal care products is much lower than that and safe to be used on the skin. Some particularly sensitive people can still be irritated by this substance but that’s rare and besides, each and every ingredient, including natural ones, used in beauty products can cause a negative reaction to someone, so there’s no need to worry. The majority of people will be able to use this ingredient without any problems at all.

Also, there is no scientific proof that Propylene Glycol causes cancer. No study has ever linked this ingredient to cancer and according to the Agency for Toxic Substances & Disease Registry it isn’t carcinogenic at all. I have no idea how or when this rumour started but it’s a relief it’s completely unfounded, isn’t it?

The Bottom Line

There’s no need to panic and run to your cabinet to throw out all products that contain Propylene Glycol. This ingredient is safe to be used in cosmetics and personal care products and won’t harm your skin nor cause cancer. :)

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  1. says

    Thanks for this article Gio! I don’t know much about all these ingredients but since you started writing about them I started learning. Just the other days I was talking with my friends over a cup of Vanilla Smoothie about how important is to know a lil bit about these ingredients. I showed them your blog so they can start learning about all these ingredients contained in cosmetic products so they will know what is good or not for their skin. They even liked your article about Nivea products because some of them were still using some of Nivea products with those old formulas. :) Thanks again and keep posting. :)
    .-= Tavia´s last blog ..L’Oreal Paris Studio Secrets Professional – New Spring 2010 Products =-.

  2. beautifulwithbrains says

    Tavia, you’re welcome and thanks for telling your friends about my little blog. :) I’m glad that they found the Nivea article interesting cos there are so much better products out there that will benefit skin a lot more than those basic, and often irritating formulas from Nivea. And I agree with you that it’s very important to know what the ingredients do so that we can choose the best products for our skin and keep it healthy, hydrated and young. And if I can help someone know more about all that, then I’m glad 😉

    • beautifulwithbrains says

      Ecopunk, thank you for the link. However MSDS refer to 100% undiluted Propylene Glycol. In cosmetics, it is used in much smaller amounts that don’t pose a threat to human health. I know I’ve said it before, but it is the dose that makes the poison. Even water is toxic in very high concentrations, but drinking it in moderate amounts is very good for you as we need it to function properly.

  3. Stephen says

    I’ve been avoiding this ingredient for a long time. My question is if PG can help the absorption of other ingredients into the skin, couldn’t that be dangerous due to pollution already in the environment? I live in NYC, and it’s not the cleanest place in the world. Also this is still a petroleum derived compound is it not. I have not use petroleum on my body in quite some time.


    • beautifulwithbrains says

      Stephen, that’s a good question. But after writing this post, I came across this article on Colin’s Beauty Pages ( that states you need to use a high amount of propylene glycol to enhance penetration of other ingredients. And because that amount could be irritating, Propylene Glycol is rarely used as a carrier in cosmetics. Usually its concentration is too small to allow other ingredients to penetrate the skin properly, so I wouldn’t worry about it too much.

      And yes, it is derived from petroleum, but that’s not necessarily a bad thing. Petroleum-derived compounds undergo a strict refining process at the end of which their molecules don’t even resemble oil anymore. They are different substances with different benefits and different side effects.

  4. lsl493 says

    I have recently quit smoking cigarettes with the help of vapor electronic cigs. I found it to be the only thing that has helped me stop smoking. It contains PG. Now I am concerned about this. Any input would be appreciated.

    • beautifulwithbrains says

      Isl493, good for you for quitting cigarettes. Propylene Glycol is a substance that’s classifies as GRAS (generally recognized as safe) by the FDA. While it is true that we don’t know the effects of inhaling it often as ecigs are so recent, I highly doubt that it is more harmful than traditional cigarettes, which have been proven to deliver toxic and carcinogenic substances generated by burning tobacco. I hope this helps.

    • beautifulwithbrains says

      Jason, probably because of the bad reputation Propylene Glycol has gained. Substituting an ingredient is easier than educating people.

  5. Tianachuang says

    Thank you for the very informative article in this great website! I wanted to know what would be the purpose of propylene glycol for hair products? Would it considered be considered an alcohol ? If it’s in a hair product (specifically to provide moisture) would it be absorped and become lactic acid or actually dry the hair more being an alcohol?


    • Tianachuang says

      One more question, are there other ingredients that would serve as a reference that the propylene glycol is acting as a binder for?

    • Gio says

      Tianachuang, glad you enjoyed the article. Propylene Glycol is a small molecule with two alcohol (hydroxyl) groups (-OH), but it is not drying. It is mostly used as a humectant, to attract moisture from the environment into the hair. This can cause frizz in some people, but overall, this ingredient is safe.

      Also, I’m not sure I understand your last question. But propylene glycol can also help active ingredients to penetrate the skin better, so you need to be careful not to use it with anything that could be irritating.

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