Is Propylene Glycol Safe?

Posted by Kevin Pierce on Feb 2nd 2015

Is Propylene Glycol Safe?

There is a lot of confusing information swirling around the Internet about e-cigarettes, and their ingredients.

Much of this is due to the many groups working to lump vaping into the same class as smoking tobacco products.

In their rush to stamp out everything that even resembles smoking, they often present half-truths and outright misinformation to prove their position.

Recently, I have seen several news items stating that propylene glycol (PG) is a toxin. This particularly questionable article from Live Science even goes so far as to link to a CDC page as proof. While it’s true that the page is found on their toxic substances portal, that doesn’t tell the full story. The following are just a few of the chemicals found on the same list of toxins:

  1. Zinc
    1. As in, the stuff that supposedly makes Zycam work to cure your cold.
  2. Nitrates and Nitrites
  3. Nickle
  4. Iodine
  5. Fluoride
  6. Aluminum

In reality, the Toxic Substances Portal is a compilation of household chemicals that are known to be potentially toxic at some level of exposure. Many of which, are commonly used in food and medicine.

Had the author done even 15 minutes of investigation, they would have learned that PG is used primarily in applications where a leak may cause it to come in contact with food products because it is accepted as far safer than its counterpart, ethylene glycol.

PG is used as the main ingredient of many intravenous medications, precisely because it is so safe.

The very same portal has this to say on its propylene glycol fact sheet:

Although propylene glycol is nontoxic under normal conditions, it can cause poisoning in rare and unusual circumstances.

In one case, an 8-month-old infant with large surface area second-degree and third-degree burns was treated for many days with topical silver sulfadiazine containing a large amount of propylene glycol. The infant developed acute metabolic acidosis and cardiorespiratory arrest. The daily dose of propylene glycol was 9,000 mg/kg. Serum propylene glycol levels were highest on day 14 (1,059 mg/dL) when the osmolal gap was 75 mOsm/L (normal: <10 mOsm/L) (Fligner, Jack et al. 1985).

As to levels required to risk toxicity,

There is no workplace or environmental standard for propylene glycol. FDA considers an average daily dietary intake of 23 mg/kg of body weight to be safe for persons 2-65 years of age (Agency for Toxic Substances and Disease Registry 1997).

So, if I were drink2.3 milliliters of pure PG, or 5 milliliters of Badger Juice, every day,I would not be at risk for propylene glycol toxicity. When PG is inhaled as a vapor, the level of absorption is dramatically lower. It would be impossible for someone to overexpose themselves to PG through vaping.

Furthermore, the CDC states that the elimination half-life of propylene glycol is just four hours, meaning that it stays in your system for a very short period of time.

To make a long story short, despite the wealth of misinformation about propylene glycol and e-cigarettes, the facts just do not support the idea that either is toxic. They are left arguing that we “just don’t know” what the harm “might be”.

Well, I also just don’t know for sure that I would not turn into a one-eyed ogre if I ever stepped foot in Paris. After all, I’ve never been there. But if someone offered me a free trip, I think I’d be willing to risk it.

*this post originally appeared at the Vapor Cafe Blog