Propylene glycol is a substance used food additive. In European countries, this additive was declared safe hence used in preserving most of the foods in stores.

Propylene glycol is commonly confused with another substance known as ethylene glycol. However, they are two different substances. Ethylene glycol is very toxic and can not be used in food processing.

Propylene glycol is also known as 1,2-propanediol, methyl ethyl glycol, or trimethyl glycol. It is a colorless, odorless substance that is in the same chemical group as alcohol. It is used as an antifreeze due to its low melting point. However, some people question its safety;this blog will help you understand why, where it is used, and its effects.

How propylene glycol is used

Propylene glycol is used in foods to prolong their shelf life, improve color, flavor, appearance, and texture. To achieve these, it is appliedin the following ways infood processing.

  • Preserving moisture. This substance is added to food during processing to prevent them from drying out and cracking. It preserves the moisture in the food and prevents it from going bad. For this purpose, it is used in foods such as nuts and coconut flakes.
  • Dissolving agent. It is used to dissolve other food additives such as color, flavor, and nutrients to enhance appearance, taste, and nutrients. It is also used to add antioxidants in packed foods.
  • Anti-caking agent. Propylene glycol may be used to prevent food substances from clumping together. By preventing clumping, it helps the food to retain its original state long after processing of prepared. Such foods include soups and cheese.
  • Texturizer. This additive can be used to change the texture of foods. It makes food softer and changes its appearance.
  • Antioxidants. Oxidation of food decreases their shelf life. Once food undergoes oxidation, they become toxic. Propylene glycol can be added to foods during processing to prevent oxidation hence prolonging the food’s shelf life.
  • Food thickener. Propylene can be used during or after processing to bring food components together thickening the food being processed. For this purpose, it is used in cakes to bring several components such as flour and fruit cakes together.
  • Strengthening dough. It is used to strengthen gluten and starch in dough making it stable. The stability prevents the cracking of dough during baking. It also prevents the hardening and cracking of foods made from dough.
  • Processing aid. It is sometimes used during food processing to enhance the appearance of the food being made. It may be used to make some liquids such as soup clearer.
  • Emulsifier. Propylene glycol is used to bring food together or prevent the separation of ingredients such as vinegar and oil in the baking of cakes or salad dressing. It brings the ingredients together preventing distortion of the original shape and appearance of food.

How safe is propylene glycol in food?

There exist conflicting information about the safety of this substance. American and European countries have declared this substance safe for use in food during or after processing. There is only one documented case of toxicity caused by propylene glycol which was caused by excess consumption. 

There are recommendations on the amount of the substance to be used in a day by different individuals. Those weighing 25 kilograms and below should not take more than 12 mg of propylene glycol. Taking excess of this substance might be toxic.

Signs of toxicity with this substance are a slow rate of breathing, unconsciousness, and decreased heart rate. In case of excess consumption, hemodialysis may be done to eliminate the substance from the body. There are also some documented cases of allergic reactions. Therefore, to be safe, you should reduce the intake of this substance by avoiding dietary sources of propylene glycol. However, this substance does not cause cancer, lifestyle diseases, death, or fertility issues. Propylene glycol may affect some special groups of people such as:

Pregnant women

Propylene glycol is broken down by alcohol dehydrogenase. Pregnant women do not have enough of this enzyme, therefore, they might develop toxicity if exposed to propylene glycol in a large amount. They should take a little amount of the substance or avoid it if possible.


Children and infants below four years should also avoid taking large amounts of this substance. They do not have enough enzymes to break it down putting them at risk of toxicity. Infants may take three times long as adults would to remove the substance from their bodies. Therefore, parents should ensure their kids do not take this substance in excess.

Patients with kidney disease

Patients with kidney disease may take a long to eliminate propylene from the body. Those who are critically ill should avoid propylene at all costs. Those with mild cases can take lower doses of propylene to avoid toxicity.

Patients with liver disease

People with normal liver take a short period to eliminate propylene from the body. Those with liver disease may take longer or sometimes the liver may not be able to eliminate the substance making it accumulate to toxic levels. Therefore, these patients should avoid taking propylene.

Patients with heart disease

A high intake of propylene glycol leads to a drop in blood pressure and changes in the heart rate. This may increase the chances of developing serious complications in patients with an existing heart condition. It can also cause a heart attack if ingested in high doses to those who do not have a pre-existing heart condition.

People with sensitive skin

Some people are sensitive to propylene and may develop serious skin reactions. They develop rashes with a high intake of this substance. Therefore, such people should avoid any dietary source of propylene or use it on their skin.


Propylene glycol is a substance used during or after food processing. It is used as an antioxidant, dough strengthener, moisturizer, thickener, and texturizer. It is generally safe for use by healthy adults. Pregnant mothers and infants should avoid it as it may take a lot of time to be eliminated from the body. Those with pre-existing health conditions such as liver, kidney, and heart disease are at risk of developing toxicity with the substance. Therefore, they should take a low amount of propylene glycol or avoid it.

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MS, University of Tartu
Sleep specialist

Using the acquired academic and professional experience, I advise patients with various complaints about mental health - depressed mood, nervousness, lack of energy and interest, sleep disorders, panic attacks, obsessive thoughts and anxieties, difficulty concentrating, and stress. In my free time, I love to paint and go on long walks on the beach. One of my latest obsessions is sudoku – a wonderful activity to calm an unease mind.

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