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From the sound of its name, it’s probably no surprise that propylene glycol is a synthetic chemical. (It’s actually the main ingredient in antifreeze!) And although its safety is questionable, it’s an incredibly common food additive that the FDA considers “Generally Recognized As Safe” (along with artificial food dyes).
Have you ever seen propylene glycol on a nutrition label and wondered, is it safe? Me too, and here’s what I found out!
What Is Propylene Glycol?
Propylene glycol is derived from petroleum and is a viscous colorless, odorless substance with a sweet taste. Food makers value it for its ability to keep a substance moist, maintain texture, and mix with almost anything (oil, alcohol, and water). Because of these properties and because it is generally recognized as safe, it has become a common food additive in processed or ready-made food items.
Processed food items containing propylene glycol are typically foods that require thickening, emulsifying, or stabilizing properties. These include:
- Salad dressing
- Liquid artificial flavoring
- Ice cream
- Artificial sweetener
- Icing
- Soft drinks
- Soups
- Puddings and desserts
- Sauces and dips
Propylene glycol is also often added to body care products, cosmetics, and medications.
Is Propylene Glycol Safe?
The safety of propylene glycol depends on the dose and individual susceptibility. So it is possible that if you are 100% healthy, exposure to small amounts once in a blue moon might be okay.
Unfortunately, when people consume the processed foods listed above, they usually consume a sizable amount on a regular basis, which is definitely not healthy.
Physiological Side Effects of Propylene Glycol
Consumption of propylene glycol has many known effects … here are the biggies.
Acidifies the Blood
Propylene glycol absorbs very quickly in the small intestine with peak levels detected in the blood about an hour after ingestion. It is also quickly eliminated (almost 50% of what is consumed is left after 4 hours).
About 55% of this is metabolized into lactic and pyruvic acids, while the remaining is eliminated by the kidneys (source).
These lactic and pyruvic acids make the blood more acidic. At low doses, the kidneys can immediately re-balance the blood alkalinity. But higher doses of propylene glycol can acidify the blood, injure the kidneys, and cause toxicity. This is why consistent consumption in large amounts is a bad idea.
In a large enough amount it can acidify the blood to the point that it requires emergency medical care. There are a few case reports, including in the New England Journal of Medicine, when patients injected with psychiatric drugs containing propylene glycol were shown to quickly develop acidosis that can cause a coma and kidney failure. Propylene glycol toxicity can also result in similar symptoms to sepsis or severe inflammatory response syndrome (source).
While it is possible to achieve this dosage level by ingesting it, this reaction is typically only reported when it is administered at a very high dose of over ~2 grams (source).
Contributes to Leaky Cells and Leaky Gut
Like soap, propylene glycol is a surfactant, which means it can break the barrier between fat and water. Our cell membranes are made with thin layers of fat molecules, which can be easily disrupted by surfactants like propylene glycol.
Pharmaceutical companies capitalize on this property by mixing or chemically binding drug molecules to propylene glycol to increase the drug absorption rate (source). This is the case for both drugs that are taken orally and topically.
Cells exposed to propylene glycol become more permeable to other molecules (source). (This is why the safety of e-cigarettes containing propylene glycol together with nicotine and cancer-causing substances is very questionable).
Currently, there is no study that directly tests whether propylene glycol causes leaky gut and the inflammatory health problems caused by the leaky gut. However, in a test tube study, propylene glycol even at low concentration destroyed some gut cells (source).
Those who struggle with leaky gut, autoimmune diseases, or digestive issues, may want to consider avoiding propylene glycol for these reasons.
Increases Risks of Childhood Allergies & Asthma
And if that’s not enough, it may affect our kids as well.
As a volatile organic compound (VOC) emitted from building materials, furniture, paint, carpet and the like, propylene glycol can aggravate the immune system. In a study evaluating the effects of propylene glycol and glycol ether vapors in the air on preschool children’s health, the authors found that the presence of such chemicals in a child’s bedroom air is associated with:
- 1.5-fold increased risks of asthma
- 2.8-fold increased risks of allergic rhinitis (hay fever)
- 1.6-fold increased risks of eczema (source)
A good air purifier can help remove airborne chemicals and is a great idea in any sleeping space.
Irritates the Skin
Propylene glycol has been reported as a skin irritant that can cause dermatitis, an eczema-like rash (source). When added to skin, body care, and cosmetic products, it can really aggravate skin problems. (Ironically, it is often an ingredient in topical medications to treat these skin conditions! How does that make sense?!)
When to Avoid Propylene Glycol
Some people are more sensitive to the side effects of propylene glycol than others. Those who are generally cautioned to avoid it are:
- People with liver or kidney problems, because the liver and kidneys are responsible for eliminating propylene glycol and its byproducts
- Pregnant women, babies, and infants as they have reduced ability to handle these types of ingredients (source)
- People with inflammatory health problems because it can irritate cells and cause leaky gut
- People with digestive problems because it will further irritate the gut cells
Fortunately, it is possible to avoid and/or reduce your exposure to as much as possible.
How to Avoid Propylene Glycol
Unfortunately, this additive is in a lot of common products, so it takes some diligence to avoid it! A few tips:
Avoid Processed Foods
The best way to avoid foods dangerous ingredients such as propylene glycol is to eat home-cooked meals the majority of the time. Fake ingredients are not necessary to make food delicious. It is possible to replace the effects of these types of additives with other, natural ingredients, such as gluten-free starch or gelatin as a thickener or stabilizer.
Read Labels and Buy from Trustworthy Brands
Always check the labels of your food ingredients and other household products for propylene glycol and its synonym, propane-1,2-diol.
I like to use brands that never put such dangerous ingredients in their products, like Primal Kitchen for mayonnaise for sauces and dressings.
Check Your Skincare, Body Care, and Home Care Products
Propylene glycol is everywhere in conventional products that people put on their skin every single day. Not only that, these skin products often contain other toxic chemicals that will be more readily absorbed through your skin because it makes your skin more permeable.
Instead, rely on organic products or make your own beauty products instead.
Use Air and Water Purifiers
Despite best efforts to avoid propylene glycol in foods and other products, exposure is still possible in the air or water in your home. Good ventilation (including opening windows to air the house out), a good air purifier in sleeping rooms, and a water filter for drinking and shower water are important.
We’ve tried several filters over the years and I’ve given my review of the best air and water filter options we’ve found.
Have you ever had a reaction to propylene glycol? Which food additives do you say “no” to for your family? Please share with me in the comments!
I was recommended to take Miralax after hernia surgery for severe constipation, and it’s propylene glycol! Have had EXTREME hair loss since taking it & lots of swelling in lower stomach. Found some research on Miralax causing hair loss, & stats for hair loss as a side effect were particularly high with Caucasian women between the ages of 40-49. This info needs to be more widely known so that people can choose better options! I just hope my hair will grow back with time. This is very disheartening.
I’m a hair stylist and I had a terrible case of dermatitis on my hands. Was referred to specialist and had the patch allergy test on my back..results showed I had a reaction to propylene glycol…I now wear gloves at work except for haircuts and blow drying.
I have also been tested positive for a propylene glycol allergy a year ago. It wasn’t until last month did I start having anaphylaxis reactions and started caring an EpiPen. I am glad to know I’m not the only one that is having these severe reactions. The one that has been really hard for me to give up is flavored coffee’s and soda however.
Good article. I would add to the list of those who should avoid PG “people who are allergic to it.” I try to read labels, but it’s hard to read the label when you go to the doctor and he 1. uses a lubricant with PEG — without telling you, despite your telling him about your PEG allergy — to perform a colonoscopy; 2. the anesthesiologist gives you Propofol as a sedative without telling you it has PG in it, despite his knowing about your PEG allergy; 3. you are sedated and in anaphylactic shock when you are rushed to the ER where, instead of treating you for anaphylaxis, they suspect an embolism — despite your having been to that same ER a few months earlier for PEG allergy — and use a sonogram gel containing PG, give you a CT-scan with a contrast containing PG, attach patch monitors containing PG to you, and give you IV corticosteroids containing PG, the very thing that caused your anaphylaxis. (It might have been the PEG or both PEG and PG. I’m working with an allergist to try to get to the bottom of it. I was not using any medications, am generally healthy, and had been fasting for the colonoscopy.) I will start wearing a medical bracelet, certainly, and I will have someone in the room with me the next time I get a colonoscopy to remind everyone that I have allergies in case something similar happens. PG allergy can be life-threatening. I’ve Googled it, and there are a lot of case studies but not enough research — none that the manufacturers want us to know about, anyway.
Hi Katie,
I was more lax and had some iced Capps with my last pregnancy. She ended up with intestinal adhesions and a twist.it has been awful to think I may have done this to her. I had no idea of these ingredients in iced Capps and avoided caffeine with my first three pregnancies but wasn’t as careful this time. I believe she may have had propylene glycol toxicity as I am not great at drinking water and was trying to keep up with my other three. The docs say it was nothing I did but I haven’t asked about toxicity, only fear of caffeine. They also suspected sepsis but never found anything, which you allude to in your article. Any insight? Thank you!
I know with other ingredients there is always the possibility within the industry that “small amounts” are not making their way to the list of ingredients. Is this the case with PG? There are so many foods that require emulsification and I am curious only because very rarely do I buy processed food it when i do I would like to be able to trust the label
Excellent article! Thank you!
I just found out that Starbucks new Simple Syrups number one ingredient is propylene glycol. Add “sugar” water and artificial and natural flavors.
1. Propylene glycol can also be derived from vegetable glycerin.
2. Acids of many kinds are normal metabolic byproducts and they do not “make the blood more acidic.” You have cherry picked the cited source, which goes on to say “Both of these metabolites are normal constituents of the citric acid cycle and are further metabolized to carbon dioxide and water.”
3. Your alarming headline “Contributes to leaky cells and leaky gut” is followed the correct statement “Currently, there is no study that directly tests whether propylene glycol causes leaky gut and the inflammatory health problems caused by the leaky gut.”
4. VOC: PLoS One is an open access site that charges authors $1,495 to publish their work and does not require conclusions to be valid. The authors themselves state they are “propos[ing] a novel hypothesis,” not proving anything. You have again cherry-picked the source and left out the part where the authors conclude “[A]pparently elevated likelihood of the present outcomes was not driven by propylene glycol, most abundant PGE compound.”
5. The source for your statement that “Pregnant women, babies, and infants . . . have reduced ability to handle these types of ingredients” refers to propylene glycol injected intravenously. You can be sure pregnant women and babies would have the same problems as anyone else if they injected avocado oil or egg yolks (Primal Kitchen Mayo ingredients) intravenously rather than eating them.
Thank you for posting your reply. I am waiting for her to do an article on dihydrogen monoxide which is in so many more things than propylene glycol and there are many more deaths attributed to it.
I just got a package of Market Street Classics premium chili, no beans and on the package it boasts that is has 63% less sodium than USDA chili! Oh but they added propylene glycol, …and they are worried about too much salt?
So, my OB doctor recommended Miralax to me for the constipation I experience during pregnancy. She said something about it being a gentler option than Colace. Miralax is straight proplene glycol. I only take it when absolutely necessary and haven’t experienced any side effects from it thus far. I have tried natural options like prunes and pineapple juice, but the Miralax seems to be the only thing that will work when I have a problem. Not sure what I should do.
Try a magnesium supplement.
So why in the world do consumers allow this freaking crap to continue? Food addiction…? The FDA doesn’t have our best interests in mind.
My encounters with Propylene Glycol were on a Christmas holiday. Both then in a chocolate food manufactured in Canada and later at home in another state I ate a small blueberry pies. Both contained PG and both kept me up ALL night with itching. Subsequently I contacted the Canadian by letter with what I experienced,, and asked them to find a non-toxic substitute for the Propylene Glycol. Likewise, I contacted the pie manufacturer, which by the way had their product in Walmarts. This happened in 2009, and I pursued this line since I saw it as a damaging threat to children, and to most adults.
This message I received from another author tells more:
“I have a friend that also found that she reacts to propylene glycol in food.
She has itching and notices a mood change – she says she gets
Very mean and says things that she would never say normally.
After finding Propylene Glycol listed as the second ingredient (after water) in the imitation Vanilla Flavoring I add to my daily morning oatmeal, I searched Online for information about the ingredient. The search led me to your website and this article. I want to thank you for this information. My eyes have certainly been opened. It makes me wonder if this is what has been adding to my digestive issues lately.
I try to avoid this chemical as well, but I’ve noticed some of the Watkins and other brands of flavorings contain it. Do you have some flavorings like caramel, butter, coconut, maple, etc that you use which do not contain it? Thanks!
I just use real food ingredients for those kinds of flavors.
I’m allergic to PG and the whole “family” of glycols. Avoidance is VERY difficult—they are everywhere! And no, I do not consider them safe as food grade or otherwise.