Propylene Glycol

The addition of propylene glycol to food and cosmetics has been controversial since it was first used. Many reports link exposure to health problems like allergies in children and developmental issues in adults. So what is the real impact of this chemical?

Propylene glycol is a chemical compound that can be found in medications, food, and cosmetics. It is used as an additive to help products stay moist or thin. Unfortunately, some people have reported allergic reactions to propylene glycol.


Nobody loves hearing that propylene glycol, an antifreeze component, is also present in food. But, just what does it imply?

Propylene glycol, a chemical molecule, has caused a lot of irritation and misunderstanding in recent years. It’s present in various items in varying levels, and some individuals believe it’s completely innocuous, while others think it’s to blame for deadly illnesses like cancer.

The reality regarding propylene glycol (like with most things!) is a little more convoluted. While there is an insufficient study on this drug in many circumstances, it is nevertheless a permissible component in many meals, including flavored iced coffees and other items. Continue reading to learn more.

What Is Propylene Glycol and How Does It Work?

Propylene glycol (also known as PG) is the third “product” of a chemical reaction that starts with propene, a result of fossil fuel processing (oil refining and natural gas processing) that is also present in nature as a byproduct of fermentation. Next, propene is transformed to propylene oxide, a volatile chemical that is often employed in the polyurethane plastics manufacturing process (and to create propylene glycol). Propylene oxide is a “probable carcinogen,” according to the EPA. Finally, propylene glycol is obtained by a hydrolyzation process (the separation of molecules by adding water).

Propylene glycol is a synthetic liquid that absorbs water and has the chemical formula C3H8O2. Propylene glycol (1, 2-propanediol) is a tasteless, odorless, and colorless transparent oily liquid that is an organic chemical (diol alcohol). Another term for it is “propane-1,2-diol,” which is occasionally used on ingredient labels when identifying it as a component. Because it’s used as a food additive (at least in the United States), the US Department of Agriculture assigns it the E-number E1520. It’s fully water-soluble, and one of its main uses is as a “vehicle” for topical preparations like lotions.

Propylene glycol can be found in tens of thousands of cosmetics and a large number of processed foods. It’s also found in many medications, where it’s used to help your body absorb chemicals more efficiently. It’s also a frequent element in electronic cigarettes, where it contributes to the smoke’s flavor and “smoothness.”

There are many different viewpoints on whether propylene glycol is a hazardous toxin or a mainly safe molecule, and there are numerous contradictions in studies. However, there is no clear and fast answer to that issue; according to a significant number of studies, propylene glycol’s effects are seldom unfavorable and are usually connected with exceptionally high intravenous dose levels.

It’s undoubtedly safer than ethylene glycol, a hazardous chemical component still found in many types of antifreeze and other home items. Ethylene glycol is a hazardous chemical that is occasionally swallowed (intentionally or accidentally), necessitating emergency medical intervention due to its harmful components. Ethylene glycol in antifreeze has been blamed for the deaths of numerous domestic dogs that would consume it as it accumulated on the ground due to its sweet flavor. When propylene glycol is used instead of ethylene glycol in antifreeze products, it is referred to as “non-toxic antifreeze.”

However, this does not always allay fears. Many people are concerned about the presence of an antifreeze ingredient in their food (one that is used for deicing airplanes, no less), which has caused a stir in recent years, especially after three European countries pulled a popular alcoholic drink off the shelves due to an illegal level of propylene glycol. The error seems to have happened when the manufacturer provided the North American formula rather than the European recipe, which has six times less propylene glycol.

Consumers were both surprised and disappointed to learn that their favorite meals and beverages may include the chemical, which was made worse because it was found in so many other everyday goods. Many people grew afraid of the link between antifreeze and food, even though propylene glycol only lowers the freezing point of water (like salt) and was only added to antifreeze products to replace a more harmful chemical.

According to the Environmental Working Group’s evaluation, the amount of knowledge concerning this chemical is “fair.” Propylene glycol receives a “3” on the scale of health concerns, indicating that it poses a fairly low risk. It accurately classifies the recognized problems with propylene glycol as “allergies and immunotoxicity,” with no threat to cancer or reproductive functions. This data is based on research that is currently accessible.

In our examination of toxicity data and propylene glycol, there are a few points to keep in mind:

  1. It’s not a “bioaccumulative” substance. At typical dosages or exposure levels, Propylene glycol breaks down in the body within 48 hours in people with good kidney and liver function. Therefore, it does not accumulate in the body over time to cause toxicity.
  2. Antifreeze, polyurethane cushions, paints, and other goods containing propylene glycol are present at industrial-grade amounts. However, the amounts in food are deemed pharmaceutical-grade.
  3. Propylene glycol has been rated “generally regarded as safe” by the Food and Drug Administration (FDA) in a toxicological profile.
  4. There were no serious health issues revealed in the Centers for Disease Control and Prevention’s extensive investigation on propylene glycol’s effects and potential toxicity. “No studies were found regarding respiratory, cardiovascular, gastrointestinal, musculoskeletal, hepatic, renal, endocrine, dermal, ocular, or bodyweight effects in humans, or musculoskeletal, dermal, or ocular effects in animals after oral exposure to propylene glycol,” according to the organization’s report. Skin exposure and inhalation exposure were both mentioned in the same breath. (Nearly all of the studies presented to justify the “safety” of this substance was conducted on rats, horses, or monkeys, and many of the arguments were based on a study conducted on monkeys more than 60 years ago.)

The first three of these considerations seem to be promising. Even though this chemical compound isn’t found in nature, it seems to be harmless. But it’s what I don’t see that worries me the most: any kind of comprehensive human-based studies on its safety.


1. Allergic Reactions and Skin Irritation

Mild skin irritation, which may cause redness, is a common side effect of propylene glycol. This usually occurs in those allergic to the chemical and goes away when the body has had enough time to break down the substance.

Propylene glycol may irritate the eyes and induce mild conjunctivitis if it comes into contact with them.

2. Toxic to the Kidneys and Liver

Many IV drugs, including Lorazepam, an anxiety, and seizure therapy prescription, include propylene glycol. This medicine is often used to sedate patients with severe burns or mental patients throughout the healing process. Clinicians have detected probable renal difficulties in the form of elevated creatinine levels in the blood when Lorazepam is taken in big dosages over a lengthy period. Creatinine (a byproduct of muscle breakdown and development) levels in the circulation are generally stable. Creatinine levels that are too high indicate that the kidneys cannot process substances at a regular pace.

Propylene glycol is unlikely to be processed successfully by those who already have impaired renal function; therefore, they should avoid it if at all feasible.

The therapy of propylene glycol toxicity was examined in a 2007 research by the University of Connecticut, which also stated that it might be problematic for persons with liver disorders.

On a more positive side, propylene glycol may be able to protect your liver from the damage caused by acetaminophen, a popular headache treatment.

3. Possibly Dangerous to Infants and Pregnant Women

To safeguard their children’s health, prospective moms are normally exceedingly careful throughout and after pregnancy. It should be no different in the case of propylene glycol.

While some study claims that propylene glycol has no adverse effects on neonates (preterm newborns), it is also true that infants cannot break down this chemical as rapidly as adults can. This is due to the enzyme pathways that are still developing at the time of birth – the period of development may run anywhere from six months to four years, depending on who you ask.

Parents and expectant moms should avoid letting their children eat or be exposed to numerous potentially dangerous substances until these enzyme pathways have finished their maturation.

4. Symptoms of the Nervous System

The only area where the CDC’s toxicity profile gave propylene glycol a negative rating was in the area of neurological problems. When given orally and evaluated with a patch test to see how much of the chemical was left in their system, several persons had varying degrees of neurological problems, including lethargy, convulsions, and other unidentified “serious mental symptoms.”

According to a cat research, cats given the high amount showed “decreased activity, mental depression, and modest to moderate ataxia.”

It’s worth noting that the persons in the research mentioned above had been exposed to propylene glycol through orally delivered medicine and were most likely allergic to it.

5. Cardiovascular Complications

Propylene glycol intake has been widely linked to heart disease and symptoms, partly due to a few case studies that have sparked alarm. For example, an 8-month-old boy had a heart attack after receiving four doses of topical medication to treat a burn.

A horse was also reported to have had cardiac edema due to an incorrectly administered excessive dose of propylene glycol.

6. Breathing Problems

The effects of inhaled propylene glycol have been reported to be mixed. This is an essential difference to make since it’s a popular element in smoke machines (for theatrical shows) and other inhalable chemicals. For example, some researchers discovered larger cells in the respiratory system and nasal hemorrhaging in rats. In another example, the horse with myocardial edema that was stated before died of respiratory arrest.

Although the settings under which this research was conducted are unlikely to be replicated in people, the knowledge is still useful. Many compounds may be poisonous in large concentrations, and it’s hard to know whether or not these chemicals will build up to deadly levels, particularly in certain circumstances.

7. In some instances, it may be bioaccumulative

Propylene glycol is not considered bioaccumulative, as I previously said (builds up over time in the bloodstream). Adults who are seriously sick, on the other hand, may be an exception to this rule. For example, adults with and without renal problems have suffered an abnormal accumulation of propylene glycol when given heavy dosages of Lorazepam.

If you have kidney or liver problems that hinder your body’s capacity to digest organic substances, or if you are chronically unwell, I strongly advise you to minimize your exposure to propylene glycol as much as possible since it may behave as a toxin in these people.

A 24-year-old lady was diagnosed with pneumonia in one fascinating case study. Lorazepam was administered to her for 18 days to manage acute respiratory distress. During that time, she developed lactic acidosis, a disease characterized by a dangerously low pH level in the body. Her health improved for a while when she stopped taking the poisonous medicine, but she died later when her condition worsened again. Once again, this is an example of the uncommon (but potential) side consequences of propylene glycol buildup in your system.

8. Could Open the Door to More Harmful Chemicals

The fact that propylene glycol might let other substances into your circulation is perhaps the most alarming aspect of chronic exposure. Propylene glycol makes it easier for your skin to absorb everything it comes into touch with. Given the enormous number of toxic compounds we encounter daily, this might be much more deadly than the molecule itself.

How Can You Stay Away From It?

So, although propylene glycol may not be as dangerous as some suggest, it does raise enough red flags for me to advise against using it. I’m not the only one that thinks this way. At least one research has concluded that it should be avoided as a food additive.

When feasible, there are a few strategies to avoid propylene glycol to safeguard your overall health, hormone balance, and total chemical exposure.

1. Read the Nutritional Labels

When you buy food in a box, there’s a helpful list on the side that shows you exactly what you’re going to eat. Please make the most of it! For example, propylene glycol is sometimes referred to as “propane-1,2-diol” or “E1520” on labels.

2. Look for cosmetics that are free of potentially harmful chemicals and preservatives

Propylene glycol is used in many cosmetics; however, it is not properly controlled in the United States. Because substances are not required to be included on cosmetic packaging, you should only buy from firms that declare all ingredients on their packaging, including propylene glycol.

This isn’t just about cosmetics. The list of items that typically include this ingredient also includes lotions and baby wipes. Other things on the list that are often used for personal care include:

  1. Soap for the body
  2. Mouthwash
  3. Conditioners and shampoos
  4. Ointments
  5. Creams for the skin
  6. Deodorant
  7. Lotions
  8. Wipes for babies

3. Stay away from processed foods that may contain propylene glycol

When looking at a list of foods that include propylene glycol, you’ll find that many of them aren’t very healthy, to begin with. It’s ideal for eating as many raw, uncooked, or natural foods as possible.

This chemical may be found in a variety of foods, including:

  1. Dressings for salads
  2. Cornstarch that has been modified
  3. Margarine
  4. Cake mix from a box
  5. Soda
  6. Desserts that are frozen (ice cream, frozen yogurt, etc.)
  7. Food for dogs and cats
  8. Icing
  9. Coffee with a variety of flavors

Alternatives Made from Nature

The most natural alternatives to propylene glycol are avoiding the chemical in meals and cosmetics. Unfortunately, many food items containing propylene glycol don’t offer “propylene glycol-free” choices unless they’re handmade.

However, you are welcome to make homemade salad dressings and guilt-free (and chemical-free) sweets using some of the recipes on my website. You may also substitute raw butter for margarine in your cooking for an instant health benefit.

I recommend trying my Homemade House Cleaner recipe because propylene glycol is often included in home cleansers. In addition, there are a plethora of “green” home items on the market, both commercially accessible and DIY-friendly, that can help you significantly limit your chemical exposure.

Because electronic cigarettes include a lot of propylene glycol, e-cigarette users may want to try vegetable glycerin e-cigarettes, which are more organic – but I still advocate stopping smoking completely.

Last Thoughts

  • Propylene glycol has been used in many items for decades, including commercial antifreeze and aircraft deicing, polyurethane cushions, paint, pharmaceuticals, cosmetics, and several foods.
  • There is no big body of research on the safety of propylene glycol in humans.
  • The FDA considers propylene glycol to be “generally” safe.
  • Propylene glycol, in most cases, does not build in your body since it degrades within 48 hours of consumption or exposure.
  • Propylene glycol is water-soluble.
  • It may induce a range of mild to serious negative effects in humans. Rare occurrences imply a severe reaction to propylene glycol, which might lead to death (albeit this is improbable).
  • Propylene glycol should be avoided by anyone with liver or renal disorders, the elderly, pregnant or nursing women, and their newborns.
  • To prevent consuming or being exposed to this toxin, check the labels on your food and cosmetics and consume unprocessed foods regularly.
  • Propylene glycol is unlikely to have any severe side effects if you are exposed to it via food or cosmetics.
  • Many products in your house that contain this chemical may be replaced with DIY or organic alternatives.

Frequently Asked Questions

Is propylene glycol safe in cosmetics?

A: Propylene glycol is a compound that has been widely used in cosmetics. It is considered safe, but it can cause skin irritation and allergies in some people.

Is propylene glycol harmful to humans?

A: Yes, it is. Propylene glycol can cause several serious side effects and health problems in humans, including vomiting, coughing up blood, irregular heartbeats, breathing difficulties, seizures, and more.

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The information on this website has not been evaluated by the Food & Drug Administration or any other medical body. We do not aim to diagnose, treat, cure or prevent any illness or disease. Information is shared for educational purposes only. You must consult your doctor before acting on any content on this website, especially if you are pregnant, nursing, taking medication, or have a medical condition.


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