Thu, March 3, 2016 at 5:51 AM
[Stephanie Greenwood]

Today's Chemical:


EWG Risk Score:


What is it?

Propanediol is a clear, thick liquid used in formulas to control viscosity. Also known as 1,3 propylene glycol, it is an isomer of the more widely-used chemical, propylene glycol. 

Is it a risk?

Propanediol does not appear to pose any significant risks when used diluted in a cosmetic formula, based on current research. However, the manufacturing of propanediol does pose potential environmental and health concerns. It can be produced from acrolein, a compound found in cigarette smoke that may contribute to lung cancer. (Source) While this wouldn't pose a risk in the finished product of propanediol, there may be exposures to workers and the environment, especially if produced in countries with less-than-stringent working and environmental regulations. 

You may also see propanediol created from "natural" sources. The most widely-distributed form is made by DuPont Chemical, created from (most likely GMO) corn syrup and a genetically-modified strain of e coli bacteria. (Source)

It can also be produced from fermenting glycerol with genetically modified bacteria. (Source)

Can be a skin allergen. (Source)

Steph's Opinion:

Propanediol as a finished ingredient doesn't pose significant health risks unless you have an allergy to the ingredient. However, when you see propanediol in a product marketed as "natural," think GMOs because it has most likely been created with either genetically-modified bacteria or from GMO corn (or both.) 

Article originally appeared on Chemical of the Day (
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