What is Propylene Glycol?
Propylene Glycol, also known as PG is a viscous (thicker than water), clear and colourless liquid. It is considered odourless and tasteless. Propylene Glycol is a synthetic liquid so it is not extracted from natural recources. It is man made. Propylene Glycol is used in many applications accross many industries from foods to healthcare. Propylene Glycol is typically used as a base ingredient in E-liquid. This is the main ingredient (along with or instead of Vegetable Glycerin) that creates a vapour when heated. You will often find it used in products which are best kept moist as it help to stop products from drying out.
Is it Anti-Freeze?
Propylene Glycol has a lower freezing temperature than water. When used as an Anti-Freeze solution, it is classified as "Non Toxic AntiFreeze" and is used where accidental ingestion may be possible and for Food Processing systems.
What common products contain Propylene Glycol?
- Asthma Inhalers
- Pet Foods
- Medication / Drugs
- Tobacco Products
- Shampoo, Soaps, Cosmetics and Lotions
- Baby Wipes
What are side effects of using Propylene Glycol?
Safety In Humans
The acute oral toxicity of propylene glycol is very low, and large quantities are required to cause perceptible health damage in humans; propylene glycol is metabolized in the human body into pyruvic acid (a normal part of the glucose-metabolism process, readily converted to energy), acetic acid (handled by ethanol-metabolism), lactic acid (a normal acid generally abundant during digestion).
Serious toxicity generally occurs only at plasma concentrations over 1 g/L, which requires extremely high intake over a relatively short period of time. It would be nearly impossible to reach toxic levels by consuming foods or supplements, which contain at most 1 g/kg of PG. Cases of propylene glycol poisoning are usually related to either inappropriate intravenous administration or accidental ingestion of large quantities by children. The potential for long-term oral toxicity is also low. In one study, in 1972, 12 rats were provided with feed containing as much as 5% PG in feed over a period of 104 weeks and they showed no apparent ill effects; no data on offspring was offered.  Because of its low chronic oral toxicity, propylene glycol was classified by the U. S. Food and Drug Administration as "generally recognized as safe" (GRAS) for use as a direct food additive.
What is Vegetable Glycerin?
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- Hamilton, D. J. "Gastric Dyspepsia." The Lancet. Volume 2 1890: p306.
- Flanagan RJ; Braithwaite RA; Brown SS; Widdop B; de Wolff FA;. The International Programme on Chemical Safety: Basic Analytical Toxicology. WHO, 1995.
- National Library of Medicine;. Propylene glycol is used in antifreezes Human Toxicity Excerpts: CAS Registry Number: 57-55-6 (1,2-Propylene Glycol). Selected toxicity information from HSDB. 2005.
- Gaunt, I. F.; Carpanini, F. M. B.; Grasso, P.; Lansdown, A. B. G. (1972). "Long-term toxicity of propylene glycol in rats". Food and Cosmetics Toxicology 10 (2): 151–162. doi:10.1016/S0015-6264(72)80193-7