What Is Propylene Glycol?

Propylene glycol is form of alcohol that finds use in a variety of products ranging from antifreeze to some foods. Many people consider it to be a toxin and another additive to avoid where possible, though the reality is a little more complicated.

Propylene glycol is found in everything from brake fluid to snacks – which is cause for alarm for many people. It is a mineral oil and an alcohol that is produced via the fermentation of yeast and carbohydrates and is classified as a carbohydrate when used in foods.

What makes matters more complicated however is the fact that PG can come in a variety of different ‘grades’, each of which is suitable for different uses. Industrial grade PG for instance is the active ingredient found in many antifreeze products, polyurethane cushions, varnishes and engine coolants. However, this same type of propylene glycol is not found in our food and in fact it is a preferable alternative to ethylene glycol which was previously used in those same products until it was found to be harmful for animals. Because dogs would sometimes consume puddles of antifreeze, EG was swapped out for PG to help prevent them from becoming ill.

Regardless, as long as you don’t consume antifreeze on a regular basis, you are probably safe from PG. And if you do, then PG is likely the least of your worries.

Pharmaceutical Grade PG

Pharmaceutical grade propylene glycol however is a far less concentrated form of the same product. This makes it considerably safer, though it is not without controversy.

A lot of research has been done on the safety of pharmaceutical grade propylene glycol but the results so far are inconclusive or contradictory. This is partly because concentrations can still vary even with pharmaceutical grades and it’s not always clear what the concentrations are in specific products. Nevertheless, the use of PG is deemed safe by the WHO and FDA, the latter of which has included it in its ‘GRAS’ (Generally Recognized As Safe) list.

Potential Risks

So what are the potential risks surrounding PG? While there are no studies showing links to cancer, in vitro studies looking at mammalian cells do show that it can trigger mutations under certain conditions.

There is some concern that it may cause skin, liver and kidney damage upon contact. The Material Safety Data Sheet cites it as a ‘hazardous substance’. It has also been shown to provoke allergic reactions in eczema patients and those with skin allergies, even in very low concentrations. It also appears telling that in Europe, the substance is restricted to largely non-consumable use.


In conclusion then, how should you proceed in regard to PG?

At this current time, there is no significant evidence to suggest that the substance poses any real danger. Rather, the concern is based on just a few worrying studies and a general caution towards unnatural products that have yet to undergo significant testing.

In short then, this substance is likely safe to consume in small quantities. That said, it is also relatively easy to avoid for those who would rather steer clear.

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