Propylene Glycol: A Misunderstood Ingredient

Note – You can find a more recent and in-depth version of this post here: Propylene Glycol in E-Cigs: Is PG dangerous to inhale?

In our latest article on The Smoker’s Angel, John looks at Propylene Glycol – and pops some myths.

Propylene Glycol Anti-freeze

One charge often levelled at e-cigarettes is that they contain anti-freeze. This is quite true, as John explains:

It is also employed … as a non-toxic antifreeze in drinking water systems

Hmm – in drinking water. They left that bit out!


Anti-smoking groups often argue that we don’t know what the ingredient does to us when we inhale it. But John finds data that states:

“There are no adverse health effects via inhalation”.

(Material Safety Data sheet – Mallinckrodt Baker Inc.).

Is it toxic?

John argues that the ingredient is not normally toxic, stating:

In one study, rats were given feed containing up to 5% PG over a period of 104 weeks (2 years) and they showed no apparent ill effects.

There are websites which will tell you the opposite. These are either sponsored/controlled by companies with a vested interest, e.g. health foods, “natural” cosmetics, etc. and /or people who deliberately or through ignorance misinterpret the results, for example saying it is toxic without mentioning it is only mildly toxic in extremely high doses.

Read the full article here: Propylene Glycol: The Principal Electronic Cigarette Ingredient

16 thoughts on “Propylene Glycol: A Misunderstood Ingredient

  1. PROPYLENE GLYCOL IS NOT ANTI-FREEZE. THAT IS DIETHYLENE GLYCOL YOU ARE THINKING OF! If you are going to make inflammatory remarks about a person, product or company maybe you should do some research before spouting of lies. Propylene glycol is in asthma medication for nebulizers and inhalers and is fully approved by the FDA for delivery to the lungs in vapor form. The other ingredients in e-cigs are water, nicotine(addictive but not harmful) and flavors. They are not only safe but possibly beneficial. Studies going back as far as 1942 show that propylene glycol delivered to the lungs can ward off infections in lab mice. Users report miracles every day. My chronic bronchitis…….CURED. My doctor stood there looking at my chest xray for 20 min scratching his head. “The infections gone” he said. “No crap doc, that’s what I told you!” I Said 🙂

  2. John is not actually arguing that propylene glycol is bad – quite the opposite! If you read the complete article you will see that John says:

    “This is an important and widely used additive and as such will have been tested exhaustively and has been found to be safe. There are websites which will tell you the opposite. These are either sponsored/controlled by companies with a vested interest, eg. health foods, “natural” cosmetics, etc. and /or people who deliberately or through ignorance misinterpret the results, for example saying it is toxic without mentioning it is only mildly toxic in extremely high doses.”

    Read more:

    1. Its funny how this article flatly states that a major issue is people with vested interest skewing the facts, and the other is ignorant people misunderstanding what they are reading. The first commenter fits the description of the latter.

  3. To: Ur a Dummy: What makes you think there is only one anti-freeze? Isn’t salt an anti-freeze? So are many other substances – anything which lowers the freezing point of water could be considered an anti-freeze. Try reading what it SAYS – not what you THINK IT SAYS.
    PS. We can also offer reading glasses and/or English lessons.

  4. hello
    I suffer from depression and take citalopram anti depressants. I would like to quit smoking traditional cigarettes and start on the E Cigs. I have read that PG has adverse effects to those who suffer from anxiety or depression, which naturally, worries me. Can you suggest any recommended none PG E Cigarettes?
    Many thanks, Rachael

    1. you can vape just straight vegetable glycerin (VG) instead of the traditional PG/VG mix. this will also give you a much bigger vapor cloud upon exhale.

  5. Hi Rachael

    Please note that the electronic cigarette is not an approved cessation aid, although many smokers have managed to successfully switch to the electronic cigarette (an alternative form of nicotine usage).

    Some users prefer to use vegetable glycerine as an alternative to propylene glycol, but I believe they mix it themselves. You would need a refillable e-cigarette (like those on the

    I am not aware of normal use of PG causing depression, but be aware that you are almost certainly using PG every day – it is in many everyday products including foods, medicines, cosmetics, deodorant and even in air-conditioners.

  6. Hi

    Many thanks for the response. Il look into the vegetable glycerine as an aletnative although i dot like the thought of mixing it myself. Maybe il try the electronic cig anyway if PG is found in other things i come into contact with in day to day life.

    Thanks again

  7. Hi James,

    Its not really a source as such, i was reading some comments on a forum and a couple of depression sufferers said that when they used the PG based E Cig it made their anxiety a lot worse, so theres no actual articles on it so to speak, just peoples personal experiences. I myself suffering from anxiety would hate to feel even worse, so i will take their advice on board. Sorry i couldnt supply you with anything concrete.

    1. Rachael, I quite smoking 2 and half years ago and switched completely to E-Cig. I use eGO CTwist with refillable Viva Nova clearomizer and I mix my e-Liq myself. what you have read about PG and anxiety is very true. I have never been so short-tempered before. the problem is, VG does not give you the real sensation of smoking as much as PG does. so you might need to consider mixing VG with PG at 80%/20% each to get an optimum e=Liq.
      Good luck

  8. I have quit smoking for a year now, on September 8 2012, I use a personal vaping device aka PVD , ego twist , vision spinner, these are batteries and I like a viv nova but I prefer the Kanger pro Mini tanks , they are stanless steel, with glass tanks and they have bottom coils. They are small and they fit all the ego/vision type batteries. I do mix my own eliquid now because I want the lower nicotien level .6 or less. I use mostly vegetable glycerin and a little PG which both are food grade and kosher products. I use food grade watersoluible flavoring , and I do not vape as much as I was when I first began to quit. I felt the same way about mixing my own at first, but with all the media attraction and conflicting issues now, I want to know what is in my e-liquid. Now I do and I know what’s going on with me and my body. I donot have anxiety issues but I do have a sensitivity to PG , I prefer to have less pg in my eliquid.
    You know there is a certain amount of changes in your body that WILL happen after you quit. BTW I smoked cigarrets for 40 + years, so for a fact I have changing in my body.
    I am also dibetic type 2 but I have not gained weight since I started vaping. Now I have to make myself go out and exercise because for years I had to go outside to smoke. It’s a motivation thing now. I have enjoyed being inside and no stinky smells or allergy issues from prolong outdoor exposure. I do work , and my job takes me outside most of the day, so when I’m off I like to be inside. No I have to break over the bearer to exercise. My bad 🙂
    Hope this helps you to break over your bearers

  9. Just a quick FYI for Rachael.

    Hi Rachael 🙂

    Citalopram hydrobromide is, as I am sure you know a member of the group of medicines called SSRI’s (selective serotonin re-uptake inhibitors). To my knowledge (extensive background in the pharmaceutical industry) there is no known interaction between Propylene Glycol and the neurotransmitter receptors which act upon serotonin. Obviously a GP will be better able to advise you, assuming they are conversant with the current level of studies into SSRI’s. This class of drugs have been around a very long time and are very well thought of in terms of action. I do know of possible problems with SSRI’s and Tramadol hydrochloride which can in some cases lead to serotonin syndrome or neuroleptic malignant syndrome-like reactions, however this would involve high doses of tramadol taken concomitantly with citalopram. Tramadol also acts like an SSRI which may explain the sense of mild euphoria experienced by people who are prescribed it.

    In summary, there is no known interaction between Propylene Glycol and serotonin activated neurons 🙂

    Hopes this helps allay your fears 😀

    All the best


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