Prolonged contact with propylene glycol is essentially non-irritating to the skin, undiluted propylene glycol is minimally irritating to the eye and can produce slight transient conjunctivitis, however the eye recovers after the exposure is removed.
Inhalation of the propylene glycol vapors appears to present no significant hazard in ordinary applications. However human experience indicates that inhalation of propylene glycol mists could be irritating to some individuals. Propylene glycol does not cause sensitization and it shows no evidence of being a carcinogen or of being genotoxic.
Propylene glycol may be a powerful deterrent against pneumonia, influenza, and other respiratory diseases when vaporized and inhaled according to a study by Dr. Oswald Hope Robertson decades before the e-cigarette was invented. The study was conducted by Dr. Robertson of the University of Chicago's Billings Hospital in 1942 on inhalation of vaporized propylene glycol in laboratory mice.
A more in-depth article was printed in the 1942 issue of November 16th from TIME Magazine. Dr. Robertson placed groups of mice in a chamber and sprayed its air first with propylene glycol, then with influenza virus. All the mice lived. Then he sprayed the chamber with virus alone and all the mice died. Researchers also found that propylene glycol itself was a potent germicide. One part of glycol in 2,000,000 parts of air would within a few seconds kill concentrations of air-suspended pneumococci, streptococci and other bacteria numbering in their millions per cubic foot."
Propylene glycol is commonly found in:
- Styling mousse
- Cleansing cream
- Skin cream
- Bubble bath
- Baby powder
- After shave
- Baby wipes
If you are allergic to Propylene Glycol (PG) it doesn’t mean you can’t smoke e-cigarettes. E-liquids are available in just VG based (vegetable glycerin) and is available as an alternative to Propylene Glycol. VG also produces an odorless vapor although it is a bit thicker and sweeter than PG. VG also does not produce the same throat hit as the PG would and also doesn’t no carry the taste as well as the Propylene Glycol.