Is There Antifreeze in My Supplements?

People take supplements for a variety of reasons: to help fill nutrient gaps, to help the body age gracefully, to heed a healthcare practitioner’s advice. When choosing a supplement, they look closely at the active ingredients to confirm quantities and benefits. But how closely do they look at the inactive ingredients in supplements? And what should they do if an ingredient sounds sinister?

What’s the difference?

Sometimes two compounds may have similar-sounding names but aren’t even remotely similar. Think carbon monoxide versus carbon dioxide. Ethylene glycol, diethylene glycol, and polyethylene glycol are other examples. Ethylene glycol is a toxic compound that can be found in many common household items, such as detergents, cosmetics, and paint. Its antifreeze properties have led to its use in deicing compounds as well as in automobile engine additives. It’s important to note that ethylene glycol is not for human consumption.

Nor should diethylene glycol be ingested. This toxic ingredient can be found in household cleaners and disinfectants.

On the other hand, polyethylene glycol (PEG) is a common inactive ingredient in foods, dietary supplements, and personal care items. Manufacturers often include it in these products to keep ingredients in a well-dispersed mixture.1 PEG is nontoxic and has been approved for use as a food additive by the US Food and Drug Administration (FDA), which affirmed that it is generally recognized as safe (GRAS).2

Why is it in my supplements?

When PEG is added to supplement coatings, it helps to protect the contents from oxidation while maintaining flexibility for coating adherence.1

Are there any known health risks associated with ingesting products made with PEG?

No; PEG is approved for use worldwide in products intentionally made for human consumption.1 PEG is not bioavailable, so it exits the body without being absorbed in the intestines.


  1. Judd D. What is Polyethylene Glycol (PEG)? Accessed March 4, 2019.
  2. Food Additive Status List. US Food & Drug Administration. Accessed March 4, 2019.

Submitted by the Metagenics Marketing Team

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